Dayton Signature Series 18” subwoofer and SA1000DSP amplifier in UM18-22 enclosure

[CherylJosie]

Hi everyone,

So my Dayton AVR-A1H living room 9.4.6 home theater system is installed and impressing me with high performance Atmos surround sound rendition from a single component in optimally treated room acoustics, using Sapphire/The Speaker Company compact budget speakers purchased pre-owned at steep online discount, decades after their initial release.

Many thanks for Amir’s excellent review of the A1H. That review plus the $2K Denon discount using the prolonged-life coupon code

GXDN-TMPR​

made the choice of purchasing this receiver directly from Denon easy-peasy.

Note the denim-stuffed absorbers sitting on the window sills. There’s a third such absorber on the left rear wall, and a thick wool blanket hanging on the front left dining room wall. These absorbers plus the curtains in their illustrated positions optimally absorb early reflections from all the speakers without overly deadening the room acoustics.

The rug has two layers of carpet pad beneath it for improved absorption bandwidth of the floor bounce.

The blank wall will hold the guitars (work in process).

The most difficult part was adding the roll-out shelf slides for improved access to this 70lb behemoth, and the steel reinforcement/piano coaster mods to the substantially overloaded TV stand. The mods to the room and furniture were a substantial portion of the total investment.

This beast runs hot, so I’ve temporarily placed a squirrel cage fan powered at low voltage atop this receiver to keep the thing cool (not shown). Infrared measurements peaked at 65C atop the right side heat sink with all channels driven, which is way too hot for my taste.

I had to rework the crossovers in the WTW center speaker models that I am using for the front l/c/r because the manufacturer inexplicably added to the original SC model a woofer Zobel compensation, but miswired it to the tweeter in the SC-MKII updated version. I think there must have been a typo in the engineering change order. Ironically, Tom DeVesto and Cary Christie put their names on the model/serial number plates of these miswired speakers, taking personalized credit for the goof lol.

As far as I know, every single updated model shipped with this bonkers miswire, explaining the diverse opinions on the sound of these speakers from excellent to terrible. The SC model without the miswired mod actually measures and sounds better.

Fortunately, one of the SC-MKII speakers I bought already has a revised crossover courtesy of the prior owner, including a spare/disconnected Zobel PCB that I moved to the inside of the unrevised SC model I already owned.

I had to replace an electrolytic capacitor that the prior owner clipped out to break the circuit.

I used a replacement capacitor purchased from Parts Express, but the more important hard-to-source components were the included PCB and inductor that the prior owner thankfully left intact for me to repurpose.

Thanks to the kind soul who fixed one speaker before I bought it, while leaving behind a disconnected Zobel, my three l/c/r now have properly implemented crossovers. What luck!

The weak link in the system is the subwoofers. I have two ancient SVS PB-10s, an ancient SVS SB12-NSD, and an ancient Sapphire/The Speaker Company 10” ported subwoofer, all in the range of 300-400W each. They can’t keep up with the bass-limited channels in this open floor plan.

I’ve tentatively decided on the Dayton Signature Series 18” subwoofer SS18-22 with both voice coils wired in series 4 ohm connection

https://www.parts-express.com/Dayton-Audio-SS18-22-18-Signature-Series-DVC-Subwoofer-2-Ohm-per-Coil-295-736

in a Dayton UM22-18 4cuft enclosure

https://www.parts-express.com/Knock-Down-MDF-4-ft-Subwoofer-Cabinet-for-Dayton-Audio-Ultimax-II-18-300-5038

and driven by the brand-spanking-new Dayton SA1000DSP class D amplifier in 4 ohm bridged mode

https://www.parts-express.com/Dayton-Audio-SA1000DSP-1000-Watt-RMS-Home-Theater-Subwoofer-Amplifier-with-DSP-Auto-Room-EQ-300-796

Here’s what I don’t know.

First off, Parts Express says that 18” SS subwoofer wants a 2cuft sealed enclosure, which seems improbably small for a woofer that size.

Secondly, Parts Express declined to confirm or deny whether the SS18-22 will fit in that UM18-22 knock-down cabinet.

The published driver diameter and cutout of the SS18-22

is identical to the UM18-22 but the driver is slightly more than 1.5” deeper, calling into question whether the internal cabinet bracing will require revision

and the Dayton amp is an unknown quantity.

I’m curious whether anyone here has already used the SS18-22, whether they’ve managed to make it fit into that 4cuft enclosure by revising the internal bracing, and whether they’ve modeled its performance.

Presumably, the reason why Parts Express recommended 2cuft sealed enclosure was to keep the system power-limited rather than excursion-limited, even though such an enclosure would require an odd shape to fit such a large woofer into such a small enclosure.

I’m more interested in the 4cuft enclosure for two reasons.

1) I absolutely don’t require full output above F3, but I’m much more interested in maximizing LFE in my open floor plan. My bass limited speakers are tiny. With the A1H 450W total being the only system power in the room, these drivers will blow away the surround channels in terms of output. A larger enclosure will reduce the LFE rolloff, making for an easier EQ adjustment, and the power limiting adjustment to the amp to protect against over-excursion won’t hurt my system performance one bit.

2) the 4cuft enclosure will reach 5Hz extension with much less power consumption than the UM18-22 in the same enclosure. I don’t want to rewire dedicated power in the room. System cost has already exceeded budget even before upgrading the subwoofers, because I had to redo the carpet with vinyl plank for optimal acoustics, and route the speaker wires in the floor and ceiling, while beefing up the TV stand. The budget is squeaky tight.

The Dayton SA1000DSP class D amp is similarly integral to this design decision, with its high efficiency and low power consumption. It is currently on sale at a $240 discount, and is the best bang-for-buck amp I can find today. However, it is an unknown quantity, being hot off the assembly line.

So, I’m asking if anyone has advice for me, and I’m seriously considering sending Amir one of these new amps for testing too, provided it comes back to me when he’s done.

Your thoughts? Thanks in advance.

 

[technodanvan]

First, I have not modeled this subwoofer, but can if you like. I wouldn't be able to until later today. In general though, I'd agree that a larger cabinet is probably better for LFE. I'd be curious how the RSS460HO-4 compares though - if PE's recommendations are to be believed you could even do a vented cab around the same size. Again, I have not modeled these!

Regarding the amp I will just say what I noticed when it first released. The Hypex 502 1,000 watt plate amplifier is a little less expensive and is more of a known quantity being from Hypex. For me specifically it is even more of a known quantity because I use a pair of them to power 12" CSS SDX12 subwoofers with passive radiators. I haven't had any issues with them. They will run warm sometimes but I've never noticed fan noise. They also have DSP. I'm not saying they're better or anything, just maybe an option depending on your situation.

https://www.parts-express.com/Hypex-Direct-FusionAmp-FA502-Mono-2-Way-Plate-Amplifier-1000W-221-012?quantity=1

Of course, you'd need to find space in a cabinet for it and if you want to stick with a flat pack that would be challenging.

 

[CherylJosie]

I would very much appreciate modeling of this subwoofer. Thank you so much for the offer! I’m primarily interested in its LFE and its limiting requirements in the 4cuft flat pack with bracing mods, which is realistically my only option for a DIY given my limitations.

Likewise, given my limitations I prefer an external amp. Revising the cabinet and replacing a failed internal amp are not on my Christmas list of TBD.

My computers have been offline for nearly half a year while I’ve been renovating. My health is poor, and finding the energy to rebuild my RAID while troubleshooting likely dust-related failures in three Linux PCs has been fruitless. The move to this new place took the wind out of my sails with back injury plus long Covid on top of pre-existing disability.

I’m primarily concerned about inherent bandwidth limitations in the Dayton amp. I’m wanting to maximize LFE and target 5Hz, even though it’s unlikely I’ll reach that at significant output level in this open floor plan. Again, that 4cuft cabinet is likely my only option, so I might as well go for it with the affordable driver that has the loosest suspension and highest equivalent volume compliance.

I’m hoping that the (dual?) passive radiator plan this SS driver was optimized for doesn’t mess up its sealed response. I think they probably came up with those small enclosure numbers based upon three drivers’ worth of displacement crammed into an unbraced or minimally braced cubic enclosure with two passive radiators serving the role of massive ports. That’s my primary concern with this driver, that it might not perform well without those passive radiators.

Parts express did say that the SS18-22 outperforms the UM18-22, but didn’t elaborate. Side-day-side simulations of all three drivers including the RSS..HO might be interesting, even though I’m not considering that driver because I don’t need its high SPL mid-bass punch.

Thank you so much for the offer.

 

[technodanvan]

No problem, got to it over lunch. I do want to point out I initially thought your mention of 5 Hz was a typo, but I see that was not the case. I do not think 5 Hz is good target for this project. If you peruse other forums (unsure I am allowed to link them) you'll see some folks have several subwoofers, many of them extremely large (24" diameter, 10+ ft3, ported) in an aim to pressurize very large rooms at very low frequencies. For a single sealed 18" I think we should realistically be comparing performance around 25 Hz or so.

I used Unibox for this. There are, of course, other software packages that would work as well but they should all give similar results. I usually use Unibox first then load into VituixCAD or other packages once I've narrowed things down a bit.

First, a straight comparison of performance of the three subwoofers in a 4 ft3 (113 L) sealed box, very stuffed with acoustic fluff. Looks pretty similar across the board. The Ultimax may have a very slight advantage in the ~25-50 Hz range. Pretty uncomfortable levels here, but let's see what excursion looks like.

First is the Reference series. It has around half the Xmax of the other two, and predictably runs out of excursion before them.

Next up is the Signature Series. It seems 1,000 watts would not be too much for this subwoofer in a sealed box. Likewise, the Ultimax can seemingly handle it even better. I think these two graphs say a lot. F3 of 43 Hz (Signature Series) vs 33 Hz (Ultimax). Maximum excursion of 19 mm (out of 26 mm available) used at 20 Hz for the Signature vs 18 / 28 mm for the Ultimax.

Now, I don't know how much actual Xmax each sub has, nor do I know how much Xmech they have which may be a better indicator of subwoofer performance (depending on the sub). Those with more subwoofer experience should probably chime in, but based solely on Dayton's published specifications and given the requirement we need to use the 4 ft3 box, I think the Ultimax would be a better choice. You'd use slightly less excursion without any EQ and have slightly more excursion available for use with EQ (I assume the DSP would emulate a Linkwitz transform) to boost low end for a flatter response. I think a lot of this is just because the box is better optimized for the Ultimax. I also think the Signature Series may be designed more for car audio given the possibility it could be wired to 1 Ohm. Just my speculation based on an hour of looking at this.

Something to possibly consider though is the use of two smaller subwoofers instead of one large one. You might give up some of the deepest bass but could reduce room nodes and have a more 'even' response through the various listening positions in the room. Now, if you're the only person listening and just have one listening position maybe this isn't a huge concern. I can look into this if you like.

 

[technodanvan]

I don't know your budget or space requirements, but GSG Audio Design flat-packs might be worth looking into. They're a little more expensive but very highly regarded at another forum.

This single one is tuned to 27 Hz and is a little larger. You'd probably use a LaVoce SAF184 with it.

https://shop.gsgad.com/collections/roundover-mbm-by-gsg/products/mbm-18-by-gsgtm-roundover-series-flat-pack-single-unit

 

[CherylJosie]

No problem, got to it over lunch. I do want to point out I initially thought your mention of 5 Hz was a typo, but I see that was not the case. I do not think 5 Hz is good target for this project. If you peruse other forums (unsure I am allowed to link them) you'll see some folks have several subwoofers, many of them extremely large (24" diameter, 10+ ft3, ported) in an aim to pressurize very large rooms at very low frequencies. For a single sealed 18" I think we should realistically be comparing performance around 25 Hz or so.

I used Unibox for this. There are, of course, other software packages that would work as well but they should all give similar results. I usually use Unibox first then load into VituixCAD or other packages once I've narrowed things down a bit.

First, a straight comparison of performance of the three subwoofers in a 4 ft3 (113 L) sealed box, very stuffed with acoustic fluff. Looks pretty similar across the board. The Ultimax may have a very slight advantage in the ~25-50 Hz range. Pretty uncomfortable levels here, but let's see what excursion looks like.

View attachment 545023

First is the Reference series. It has around half the Xmax of the other two, and predictably runs out of excursion before them.

View attachment 545024

Next up is the Signature Series. It seems 1,000 watts would not be too much for this subwoofer in a sealed box. Likewise, the Ultimax can seemingly handle it even better. I think these two graphs say a lot. F3 of 43 Hz (Signature Series) vs 33 Hz (Ultimax). Maximum excursion of 19 mm (out of 26 mm available) used at 20 Hz for the Signature vs 18 / 28 mm for the Ultimax.

View attachment 545025

View attachment 545026

Now, I don't know how much actual Xmax each sub has, nor do I know how much Xmech they have which may be a better indicator of subwoofer performance (depending on the sub). Those with more subwoofer experience should probably chime in, but based solely on Dayton's published specifications and given the requirement we need to use the 4 ft3 box, I think the Ultimax would be a better choice. You'd use slightly less excursion without any EQ and have slightly more excursion available for use with EQ (I assume the DSP would emulate a Linkwitz transform) to boost low end for a flatter response. I think a lot of this is just because the box is better optimized for the Ultimax. I also think the Signature Series may be designed more for car audio given the possibility it could be wired to 1 Ohm. Just my speculation based on an hour of looking at this.

Something to possibly consider though is the use of two smaller subwoofers instead of one large one. You might give up some of the deepest bass but could reduce room nodes and have a more 'even' response through the various listening positions in the room. Now, if you're the only person listening and just have one listening position maybe this isn't a huge concern. I can look into this if you like.

The onion so much for the modeling!

Sorry for the confusion. The AVR-A1H receiver has four subwoofer outputs and I’m using all four of them. I’ll likewise have four 18” subwoofers when this project is finished.

The receiver wants those four subwoofers in the four corners of the room. My front left ‘corner’ is missing the left sidewall boundary and this affects the bass performance of the room significantly. However, I did try moving that subwoofer to the corner of the dining room area, and found that placement had inferior performance, so I moved it back.

Audyssey in the A1H provides an option of directional bass that spatially steers the bass content that has been crossed over from the bass-limited surround channels to the subwoofers. I’m currently using this directional bass steering function with four subwoofers to enhance the surround imaging of my floor and ceiling speakers, which are bass limited in bandwidth. The floor speakers roll off around 60Hz in this room, and the ceiling speakers have ~120Hz series blocking capacitors in the crossovers to protect the 3.5” woofers. The crossovers are currently set to 60Hz and 150Hz, although that may change once I get Room EQ Wizard running again.

AVR-A1H also has Dirac Live with ART (active room treatment) bass management that utilizes MIMO (multiple input/multiple output) phased array technology to actively cancel room resonance modes below 120Hz. I’m not currently using this feature because the subwoofers I’m using aren’t capable of taking full advantage of its benefit, but I do intend to purchase the license once the subwoofers are completed. I presume that large sealed subs with low group delay and low Q resonance will optimally damp room resonance modes. I also presume that the lower Q but higher frequency F3 of the Signature Series may aid ART in controlling room resonance.

Since I don’t have room for bass traps, I’m expecting that ART will significantly enhance the bass performance of the room over what I can achieve without it. Hopefully the unloading of that front left corner will also help tame the modal resonances.

The subwoofer 5Hz LFE target is based upon what people have typically achieved with the Ultimax driver. I’m aware that an open floor plan will substantially attenuate 5Hz when the cabin gain of pressurization isn’t available. However, this joist suspension floor should give a pretty good shake, and I can’t really blast the bass in here without drowning out the receiver anyway. Modest 5Hz output might add just enough ‘kick’ to enhance the action flick experience slightly, at zero additional cost.

My reason for considering the Signature Series is evident in the modeling you did. At 10Hz with similar power level, the Signature Series has about 1dB more output and 4mm more excursion, with a more gradual rolloff than the Ultimax.

The thing I don’t know is what happens through 1Hz with 1000w, whether that Signature Series driver runs out of excursion, and most especially with the amp being an unknown quantity, I don’t know if it has maybe more or less output that might also affect the safety margin.

The Ultimax is a known quantity that has some motor noise and good safety margin at full power in its 4cuft enclosure. The Signature Series is a newer driver that Parts Express said outperforms the Ultimax, but without modeling in the enclosure and verification of the amplifier output, I can’t predict the safety margin on Xmax. I also don’t have insight into the bandwidth of that amplifier, whether it produces flat frequency response to 5Hz or lower.

These are the factors that would sway my decision between the two drivers. Most especially, if I get more output at 5Hz from the Signature Series driver using that same amplifier, but without risking over-excursion, I’d choose that driver. If the Ultimax generates more output to 5Hz at full rated power, I’d consider that driver, but I’d have to weight the additional cost of an amp with a couple hundred more watts, and the cost of dedicated power to run it.

I hope that clarifies things.

 

[CherylJosie]

Gack. The autocorrect mangled things, I didn’t catch all of them, and I can’t seem to edit my post after the fact.

I meant to say thanks so much for the modeling.

 

[Digital_Thor]

One of my friends have 4 Dayton RSS390HF in 120 liters closed - later he went vented, for added "ompf" he likes that. It plays thundering clean articulate bass in his very large living room, with one subwoofer in each corner.
Still, we agree that these are quality subwoofers, where they give you much more freedom to cross higher and in general the bass seems better than most subwoofers that are purely built for excursion, power and extension in small cabinets.
The price is a larger box.
https://daytonaudio.com/product/126/rss390hf-4-15-reference-hf-subwoofer-4-ohm

I have two of them, also in 120 liters closed + two 12" Scan-speak Discovery in 90 liter closed. One is crossed at 150Hz, and it still sounds great. My in-room response is way below 20Hz, though it is matter of room, setup and tuning - so your miles may vary.
If you do a reflex design with 4 x RSS390HF, you will pump that room with very clean and deep bass. Your mains can also be crossed a little higher, because they look quite small, which might de-load them a bit.
Four 18" subwoofers might be overkill in this setup. A couple of my friends have the RSS390HO, which can be pushed in 60 liters, but it is less quality sound - IME - than the HF-version in a larger cabinet. The smaller cabinet and heavier cone of the HO versions - properly also the Sig-version you look at - tends to have a bit of over-hang in the sound, creating a kinda tiny more "pumped" sound. Difficult to explain, but some actually like this, so I won't talk it down, just pointing it out, so that it is remembered that all designs in drivers, cabinets and rooms, have a sound signature, which I also believe is the reason why so many people can discuss this subject for years.
So my point is merely, that when you have a rather small speakers all around - like you mention yourself - then I believe that the HF-version would give you both plenty of head-room and freedom to tune your entire system like you want. If you go for those high output version subwoofers - which are often made for size restrictions, like in cars - then you have less freedom to play with tuning..... and you don't need those huge excursions to have deep bass... especially if you accept a bigger box.

To throw even more speculation into the mix. If you just have 1 big subwoofer, it is actually ok that the rest is smaller, if you just tune it accordingly. Meaning, you could have one or maybe two big subwoofers and let the best of the two you have left smooth out the response of the overall response. This could work because most of your room-problems are not at 20-30Hz but more between 35-40 to 120Hz for most rooms. But this could require you to have control over a dedicated HP for the subwoofers that are not capable to play very deep - especially if ported - since the cone has no "air-support" below port resonance, as you would have with a closed box.

When it comes to amplifiers, most of my friends just buy a multi-channel PA ampflier and often modify the fan, so that it's not too noisy. One has the Behringer NX4-6000 and never consider anything else for subwoofers. For EQ/DSP it seems like your Denon should have finally gotten the Dirac Live Active Room Treatment upgrade, so that it handles everything by itself - right?

 

[technodanvan]

My reason for considering the Signature Series is evident in the modeling you did. At 10Hz with similar power level, the Signature Series has about 1dB more output and 4mm more excursion, with a more gradual rolloff than the Ultimax.

Couple of random thoughts!

Four 18s will certainly get some air moving! However, I'm not sure I interpret the graphs that same way. The model shows the Signature Series may be slightly more sensitive at 10 Hz - I'll see about other software to model below that - but it uses more excursion to do it than the Ultimax. More excursion isn't really a 'good' thing, it means it has to move more in order to do roughly the same thing the Ultimax is doing. I'd also like to point out that 1dB isn't really noticeable by ear, or in this case since it's infrasonic, by tactile 'feel'.

Be careful with Dirac and the like, some of them may have an infrasonic filter built in to protect woofers. At the very least it's something you'd need to disable if you want performance below the threshold of audibility. I'm guessing it is defeatable if it does exist. Just a thought.

Be sure to look at the list of movies that contain audio below 20 Hz. It is not a very long list. Also be sure to check out which versions of those movies actually have said audio. An example - the opening scene (like, it's just a black screen before anything is even shown) of Edge of Tomorrow is well known for very deep bass...on the DTS-HD track on the blu-ray. However, if you listen to the Dolby TrueHD track on the 4K UHD disc, it's different. This is because they filtered out the infrasonics substantially, probably because people were blowing their subs on it. You probably wouldn't need to worry about this since your subs will be designed to handle it (if anything, I'd be worried about the amps) but I'm just saying this is not an isolated incident and depending on your library you might not have much going on below 20 Hz.

We didn't talk about SPL. How loud does this need to go?

I have some other thoughts but I'll wait on your response to that last question as it's pretty important.

 

[CherylJosie]

Couple of random thoughts!

Four 18s will certainly get some air moving! However, I'm not sure I interpret the graphs that same way. The model shows the Signature Series may be slightly more sensitive at 10 Hz - I'll see about other software to model below that - but it uses more excursion to do it than the Ultimax. More excursion isn't really a 'good' thing, it means it has to move more in order to do roughly the same thing the Ultimax is doing. I'd also like to point out that 1dB isn't really noticeable by ear, or in this case since it's infrasonic, by tactile 'feel'.

Be careful with Dirac and the like, some of them may have an infrasonic filter built in to protect woofers. At the very least it's something you'd need to disable if you want performance below the threshold of audibility. I'm guessing it is defeatable if it does exist. Just a thought.

Be sure to look at the list of movies that contain audio below 20 Hz. It is not a very long list. Also be sure to check out which versions of those movies actually have said audio. An example - the opening scene (like, it's just a black screen before anything is even shown) of Edge of Tomorrow is well known for very deep bass...on the DTS-HD track on the blu-ray. However, if you listen to the Dolby TrueHD track on the 4K UHD disc, it's different. This is because they filtered out the infrasonics substantially, probably because people were blowing their subs on it. You probably wouldn't need to worry about this since your subs will be designed to handle it (if anything, I'd be worried about the amps) but I'm just saying this is not an isolated incident and depending on your library you might not have much going on below 20 Hz.

We didn't talk about SPL. How loud does this need to go?

I have some other thoughts but I'll wait on your response to that last question as it's pretty important.

I’d like the subwoofers to reproduce +3dB at 20 Hz and -3dB at 5Hz. They also need good response up to 150Hz or higher, which was one reason for selecting the Signature Series.

I’ll run the system at about -3dB on action flicks, once in a while. I’m usually listening to movies at about -10dB and music at about -10dB if I’m learning a cover tune, -15dB otherwise.

Thanks for the advice on Dirac. I assumed it wasn’t going to do any rolloff except what it detects as the -3dB or -6dB LFE. I didn’t consider the possibility of hard bandwidth limitations. No I didn’t buy it yet. The Black Friday coupon had already expired by the time I got the room finished and the receiver running. I’m hoping to get it on the next discount special.

Here’s more TL;DR specifics on the system and my objectives.

This is a manufactured home on a steel frame and dates to 1976 when the regulatory split between mobile home and manufactured home was brand new in the US. Construction standards for manufactured vs mobile progressively diverged over the years from that point forward, but this particular home isn’t even as rigid as some others I shopped from this same era that had partial foundations around the perimeter instead of jacks, and drywall with wood siding. Originally this one had only six piers embedded in concrete but they have been disconnected from the steel frame and there are dozens of new jacks densely distributed under this home now to keep it level.

Although it’s a joist construction, the steel frame plus lots of densely dispersed jacks across the entire underside seems to partially negate that bounciness, but the sofa catches a lot of air and moves pretty good even with the mere 1KW I’m currently driving. Most of the impact comes from the two SVS PB10’s in the enclosed rear of the room with 18hz port tune, 10” drivers, and 300W each. Their -3dB in-room extension is good to 16Hz as measured in similar room acoustics at my prior home and they produce detectable output down to 14Hz.

The front subs aren’t nearly as good, especially given the pressure relief of the missing front left corner. Playing stereo music with 5 string or synth bass and directional bass enabled in the receiver that only uses front subs for stereo playback reveals a gaping perceptual hole below 40Hz, despite the SB12-NSD up front left measuring good to 20Hz in Audyssey. It simply doesn’t have enough output to make up for the deficiency of the Sapphire/The Speaker Company subwoofer it is paired with on the front right, and without Room EQ Wizard I’m sort of blind to the percentage of front sound stage bass suckout of the open floor plan.

Here’s the front left subwoofer eq. I added 3dB of boost at 20Hz, and then pulled 200Hz back down to 0dB.

The front right subwoofer is having problems. I’ve already replaced the 300W BASH plate amp with a similar one and didn’t bother tuning the high pass for the driver/enclosure. The new plate amp is also beginning to fail, with intermittent power-on. I had to put the 3dB boost at 40Hz because it wouldn’t generate detectable LFE down to 2OHz. The resulting response after normalizing 200Hz is somewhat flat rather than bass-boosted.

Audyssey plot doesn’t do the rear subs justice. They are rocking and rolling down to 15Hz with a tone generator. The PB10 is an amazing little subwoofer for such an old and modest design.

The windows are upgraded from single pane to dual pane and the siding is upgraded from aluminum to T11 chip board. The subfloor is particle board and I’m guessing that overlays 3/4” plywood but honestly I didn’t check carefully while my contractor installed the vinyl plank. I suspect that mere particle board would collapse over time and there must be some plywood. While we were on the roof diagnosing the leaks, I noted that the sheeting was very springy on 24” centers like a 1/2” plywood trampoline. That’s the only thing over the vaulted ceiling besides the upgraded 5/8” fire code drywall, vapor barrier, and R13 insulation.

The original finish in here was paneling. It has been covered with 3/8” sheetrock and a thin layer of rough finish wet plaster spread over that for cosmetic effect. I haven’t noted a single rattle in here, which is amazing given the abundance of rattles in my prior home that was 1/2” drywall and stucco. Perhaps the relatively soft materials on a more rigidly supported frame dampens the building resonances.

Immediately outside the building, the sound leakage isn’t extreme, but it is noticeable. The limiting factor isn’t my retired neighbors who are a mere 20’ away and just as old and deaf as I am, plus not really caring too much about noise as long as it’s not past midnight. The limiting factor is me, with my trashed hearing that can’t handle extreme SPL any more at my age, and my retirement budget that can’t accommodate high SPL capable speakers.

Here’s the calibration levels:

The maximum calibration level on the front l/c/r is -4.5dB. With total system power of 45Ow (150WPC into 3 channels) and speaker sensitivity approaching 90dB, I’m fairly confident this system is producing near reference level as long as the program content isn’t sustained at maximum SPL for more than a few milliseconds.

The surround bookshelf speakers and front height satellite speakers are about 87dB sensitivity. The rest of the height speakers are about 85dB sensitivity.

All of the ceiling speakers are bandwidth limited to 120Hz or above, best case. They were designed for small room 5.1 with a modest subwoofer, but they sound amazingly good for what they are and with proper bass management produce some impressively clean SPL given their size.

The maximum calibration level on the ceiling speakers is +3.5dB, so I don’t push the system beyond -3.5dB unless the program content is very quiet. At that level, the limiting/clipping indicator on the SVS SB12-NSD 400W is lighting solid when loud LFE is playing, and the sub bass is noticeably compressed. The rear subs have no such indicators and probably have 3dB more continuous output in the sub-bass region, being ported albeit 10” instead of 12”. The front right sub is relative garbage and barely doing anything except maybe contributing distortion below 40Hz while the rest of the system is cooking.

Here’s an example of my front sound stage bass-limited room EQ. I’ve used the maximally flat reference curve, disabled midrange compensation, and put -2dB cut at 4KHz to smooth the response. This EQ matches my native in-room response well and preserves the on-axis tonal character of the manufacturer’s anechoic response, while smoothing the in-room response. Dialog intelligibility is excellent as is surround imaging. The surround channels have similar frequency response.

This measurement is taken across all 7 seating positions (5 on the sofa and 2 on the ottoman behind it), plus one initial calibration measurement position centered roughly between all the seats (roughly sitting upright on the front edge of the modular corner which is where I do my critical listening). The measured response, when distributed so widely across the listening area, is a sound power response more than it is an MLP frequency response, and specifically chosen by me for maintaining smooth sound power response throughout the listening area, to avoid location-specific frequency response aberrations.

I’d like the subwoofers in here to produce 5Hz at reference level, or as close as I can get to it with 4x18” subs and 4x1KW class D amps, preferably at the highest efficiency I can devise with careful driver and enclosure selection. I’ll likely never require that 5Hz at reference level of the system on a long-term continuous basis, but I’m sure I’ll need it on a transient basis given my listening habits. Probably -3dB or -5dB continuous would suffice, but that’s not accounting for the 3dB room EQ boost at 20Hz, so I’m expecting some substantial sub-bass rolloff below 20Hz rather than the astronomical overpowering 5dB-10dB that true bass heads build at 5Hz or below.

I eventually plan on restoring filtered sub bass with an 8-channel miniDSP using the BassEQ coefficients published on ‘that other forum’. I won’t need all 8 channels in that MiniDSP, but I’ll need the balanced line connections. To keep the restored equalization of the programming content simple, I’d like the subwoofer amps to handle the equalization and limiting of the subwoofer hardware independently, hence the Dayton amp with DSP that I’m considering.

I’m content to build the best 5Hz I can manage on this meager budget and see what I get. If I reach single digits at -3dB, I’ll consider it a success. There’s no funding or motivation for a killer home theater, nor could I use it here. This is more of an engineering optimization exercise than it is an SPL exercise.

 

[levimax]

I’m content to build the best 5Hz I can manage on this meager budget and see what I get. If I reach single digits at -3dB, I’ll consider it a success. There’s no funding or motivation for a killer home theater, nor could I use it here. This is more of an engineering optimization exercise than it is an SPL exercise.

You have thought a lot about this project but I don't think you have a good feel for how much more difficult 5 Hz is compared to 20 Hz which is already very difficult to do well. It requires orders of magnitude more power and surface area and it is not going to happen with conventional drivers and amps like you are imagining. If you are really set on 5 Hz it will be much easier and cheaper to accomplish with a rotary subwoofer https://en.wikipedia.org/wiki/Rotary_woofer. In any case good luck and have fun.

 

[technodanvan]

I'm not sure I'd call this a meager budget! I think we can do pretty well with it actually, but as @levimax mentioned, 5 Hz is very difficult to do. Even -3 dB at something like 15-20 Hz is hard. I'm not sure where you've seen other people claim 5 Hz response out of the Ultimax or similar, but maybe you could link it here for evaluation?

I really think you should look around the GSG Audio website as it's a better value for knock down boxes of all sizes and alignments. You should start here:

PERFORMANCE COMPARISON TABLE

IMPORTANT NOTE: The performance table below is provided to give potential buyers a rough idea of how the various Cabinet/Driver/Amplifier combinations will work. Please don't use this table for comparisons to other performance tables, measured or modeled results, or other manufacturer's...

shop.gsgad.com

Downside is they can be on the large and heavy side, but they do have some sealed cabinets.

 

[CherylJosie]

I'm not sure I'd call this a meager budget! I think we can do pretty well with it actually, but as @levimax mentioned, 5 Hz is very difficult to do. Even -3 dB at something like 15-20 Hz is hard. I'm not sure where you've seen other people claim 5 Hz response out of the Ultimax or similar, but maybe you could link it here for evaluation?

I really think you should look around the GSG Audio website as it's a better value for knock down boxes of all sizes and alignments. You should start here:

PERFORMANCE COMPARISON TABLE

IMPORTANT NOTE: The performance table below is provided to give potential buyers a rough idea of how the various Cabinet/Driver/Amplifier combinations will work. Please don't use this table for comparisons to other performance tables, measured or modeled results, or other manufacturer's...

shop.gsgad.com

Downside is they can be on the large and heavy side, but they do have some sealed cabinets.

I saw three systems of note. One was Popalock’s basement system with 16xUM18-22 in 4cuft cabinets and +15dB output capability, insane pant leg action on video and large double doors movement shaking in their frame, featured I. home Theater of the Month a while back. The second was 4xUM18-22 in vertical opposed sonotube enclosures, hit single digits in a small open living room like mine, I think it did 6Hz-7Hz at reference level but they were both in enclosed corners with solid boundary support. The third was 4xUM15-22 in a small enclosed bedroom, claimed 5Hz response, but this one had no SPL measurements backing it, so the output may have been there but insignificant.

I think there’s some confusion about budget, soace, and what it means to hit 5Hz for me. I’m not expecting to rattle my teeth for $6K nor am I expecting less than 1% distortion. I’m expecting that the single digit SPL will principally be perceived as furniture and foundation movement rather than tactile SPL, and may be accompanied by substantial (and audible) harmonic distortion plus maybe some motor noise given the massive excursion at those levels.

For that amount of money I could readily expect maybe one or two internet-direct SVS or Rhythmic subwoofers that won’t sound or feel substantially different from the garbage I’m currently using at the levels I’m listening, although they could rattle the neighbor’s tea pot with 35Hz if I turned them way up, or perhaps one ginormous subwoofer in an enclosure that won’t fit anywhere in my room. With 9 floor channels and 3 guitar amps, 4x4cuft is the absolute maximum that works in here without requiring that I reposition or replace my front l/r or move my practice space to the spare bedroom, so that means I’m excluding ported enclosures for subwoofer drivers larger than 12” anyway. That pretty much rules out PA/professional drivers with excellent transient response but drastic bandwidth limitations in huge cabinets.

Inflation has radically changed the picture of what it means to have a budget for home theater hobby when grocery bills are tripled in 6 years for basic items. $6K for 5Hz is a bargain, if you can do it and are willing to settle for it.

Some day I might upgrade the bass-limited channels. I’m prepared for the lack of ‘slam’ because I’ve already compared these speakers to towers with dual 8” woofers in the same model line. I’m not prepared to do that today and it’s unlikely I’ll notice the lack of ‘slam’ with 4x18” when the rest of the speakers in the room are struggling to keep up with the SPL. I’m just looking for extended bandwidth here and credible usability with Dirac ART in sealed boxes, not professional sound quality. I’ll probably never have professional sound quality on my budget anyway.

 

[levimax]

I saw three systems of note. One was Popalock’s basement system with 16xUM18-22 in 4cuft cabinets and +15dB output capability, insane pant leg action on video and large double doors movement shaking in their frame, featured I. home Theater of the Month a while back. The second was 4xUM18-22 in vertical opposed sonotube enclosures, hit single digits in a small open living room like mine, I think it did 6Hz-7Hz at reference level but they were both in enclosed corners with solid boundary support. The third was 4xUM15-22 in a small enclosed bedroom, claimed 5Hz response, but this one had no SPL measurements backing it, so the output may have been there but insignificant.

I think there’s some confusion about budget, soace, and what it means to hit 5Hz for me. I’m not expecting to rattle my teeth for $6K nor am I expecting less than 1% distortion. I’m expecting that the single digit SPL will principally be perceived as furniture and foundation movement rather than tactile SPL, and may be accompanied by substantial (and audible) harmonic distortion plus maybe some motor noise given the massive excursion at those levels.

For that amount of money I could readily expect maybe one or two internet-direct SVS or Rhythmic subwoofers that won’t sound or feel substantially different from the garbage I’m currently using at the levels I’m listening, although they could rattle the neighbor’s tea pot with 35Hz if I turned them way up, or perhaps one ginormous subwoofer in an enclosure that won’t fit anywhere in my room. With 9 floor channels and 3 guitar amps, 4x4cuft is the absolute maximum that works in here without requiring that I reposition or replace my front l/r or move my practice space to the spare bedroom, so that means I’m excluding ported enclosures for subwoofer drivers larger than 12” anyway. That pretty much rules out PA/professional drivers with excellent transient response but drastic bandwidth limitations in huge cabinets.

Inflation has radically changed the picture of what it means to have a budget for home theater hobby when grocery bills are tripled in 6 years for basic items. $6K for 5Hz is a bargain, if you can do it and are willing to settle for it.

Some day I might upgrade the bass-limited channels. I’m prepared for the lack of ‘slam’ because I’ve already compared these speakers to towers with dual 8” woofers in the same model line. I’m not prepared to do that today and it’s unlikely I’ll notice the lack of ‘slam’ with 4x18” when the rest of the speakers in the room are struggling to keep up with the SPL. I’m just looking for extended bandwidth here and credible usability with Dirac ART in sealed boxes, not professional sound quality. I’ll probably never have professional sound quality on my budget anyway.

I have a stereo system with 2 13 cubic ft GSG subs with 18" pro drivers in a 2,200 cubic ft room which will play flat and reference level and low distortion down to ~16 Hz at midfield distance. Recently I started using ART and added 2 additional 4 cubic ft subs for support. At first I was disappointed that ART uses a brick wall 20 Hz high pass filter but after listening to the results I believe I am better off without the extra extension. The reason is that my room can not handle frequencies below 20 Hz, the drywall literally start moving and eventually banging against the studs. It adds a ton of decay like behavior and doesn't sound good at all. In addition after analysing many recordings I found very few have any content below 20 Hz and the vast majority nothing below ~35 Hz. I only found one organ CD which did have some 17 Hz content but it was more of a gimmick at the end of one song and never sounded right (unless you like the sound of drywall banging against studs).

For music at least what you are proposing can easily give "profession sound quality". My free internet advice is to forget about single digit or 5 Hz extension and instead focus on time domain accuracy and low distortion down to 20 Hz (of course to get 20 Hz right you will have extension below it). "Slam" lives between 40 Hz and 200 Hz and is sensitive to time domain issues (ringing and group delay) and needs a lot of SPL. With 4-4 cubic ft sealed subs carefully chosen or designed (if DIY which will save you a lot of money) with enough power and ART you should be able to put together a no compromise music system (That can also do car crash scenes quite well). In the future if you still feel like you need 5 Hz you can start trying Infinite Baffle or Rotary subs but I doubt you will feel the need based on listening (as opposed to looking at graphs).

 

[CherylJosie]

I have a stereo system with 2 13 cubic ft GSG subs with 18" pro drivers in a 2,200 cubic ft room which will play flat and reference level and low distortion down to ~16 Hz at midfield distance. Recently I started using ART and added 2 additional 4 cubic ft subs for support. At first I was disappointed that ART uses a brick wall 20 Hz high pass filter but after listening to the results I believe I am better off without the extra extension. The reason is that my room can not handle frequencies below 20 Hz, the drywall literally start moving and eventually banging against the studs. It adds a ton of decay like behavior and doesn't sound good at all. In addition after analysing many recordings I found very few have any content below 20 Hz and the vast majority nothing below ~35 Hz. I only found one organ CD which did have some 17 Hz content but it was more of a gimmick at the end of one song and never sounded right (unless you like the sound of drywall banging against studs).

For music at least what you are proposing can easily give "profession sound quality". My free internet advice is to forget about single digit or 5 Hz extension and instead focus on time domain accuracy and low distortion down to 20 Hz (of course to get 20 Hz right you will have extension below it). "Slam" lives between 40 Hz and 200 Hz and is sensitive to time domain issues (ringing and group delay) and needs a lot of SPL. With 4-4 cubic ft sealed subs carefully chosen or designed (if DIY which will save you a lot of money) with enough power and ART you should be able to put together a no compromise music system (That can also do car crash scenes quite well). In the future if you still feel like you need 5 Hz you can start trying Infinite Baffle or Rotary subs but I doubt you will feel the need based on listening (as opposed to looking at graphs).

I’m wondering how the SS stacks up against the UM in the time domain. I assumed that the high compliance suspension and higher free air resonance would improve the transient response which was why the Parts Express claim is that the SS outperforms the UM.

I’ll be repairing my PCs soon and might be able to get some comparison simulations going, but unsure how revealing they will be in the time domain. Probably need REW to know for sure and that presumes possession of a functional system.

This hobby is very much an exploration. Prior art is a known quantity, but when trying something new there’s always an adventure, and a risk.

 

[CherylJosie]

The guitars are hung

 

[levimax]

I’m wondering how the SS stacks up against the UM in the time domain. I assumed that the high compliance suspension and higher free air resonance would improve the transient response which was why the Parts Express claim is that the SS outperforms the UM.

I’ll be repairing my PCs soon and might be able to get some comparison simulations going, but unsure how revealing they will be in the time domain. Probably need REW to know for sure and that presumes possession of a functional system.

This hobby is very much an exploration. Prior art is a known quantity, but when trying something new there’s always an adventure, and a risk.

For a DIY sealed sub, time domain performance is usually excellent. The problems are from small commercial sealed subs that boost the low end and then need a steep high pass to prevent self destruction. This combination plays havoc with time domain behavior but makes for good advertised specs.

 

[CherylJosie]

For a DIY sealed sub, time domain performance is usually excellent. The problems are from small commercial sealed subs that boost the low end and then need a steep high pass to prevent self destruction. This combination plays havoc with time domain behavior but makes for good advertised specs.

Ah. That makes perfect sense and affirms what I believed.

It also makes me wonder about a few things…

1) Will BassEQ mess up Dirac ART? Should I maybe implement BassEQ in software ahead of the receiver, instead of doing it in DSP ahead of the subwoofer? Maybe I need to rip and transcode the audio, or at least EQ it separately and re-sample it. I haven’t put much thought into this.

2) What makes for a better time-domain 5Hz subwoofer: an Ultimax with massive bass boost or a Signature Series with slightly less EQ that starts at a higher frequency?

3) What’s better: using a limiter or a high pass to prevent over-excursion (or just using a lower power amp)?

I assumed the Umtimax was unconditionally safe in the 4cuft enclosure. I was really hoping for an excursion simulation on that SS down to 1Hz. If I can let it run free without worry, that seems like the best solution. That was another reason for investigating that Dayton amp. It’s a couple hundred watts shy of the SS max power spec and should obviate any need for output limiting in that enclosure.

I’m also going to have to contact Dirac and find out if ART is going to add value to my system. If Dirac Live is going to truncate response below 20Hz and ART is also going to truncate response below 20Hz that’s bad. If it’s going to leave everything below 20Hz unEQ’d I can live with that, although it’s less than ideal. ART uses all the bass-capable channels so I don’t see how it can ignore frequencies below 20Hz.

 

[Digital_Thor]

This is my response in a 65 sqm room, with 2x15" RSS390HF + 2x12" Scanspeak 30W/4558T00 - combined with mains with 2xWO24P - all closed - smoothed together with MSO.
Best bass I've ever had.
Extension, and seamless integration between mains and subwoofers, so that I had a smooth overall bass around the room, was my goal..... with minimum DSP trickery.
I have only very little delay on 3 of the subwoofers, and no FIR, all-pass and only 2-3 PEQS on each bass source.... so very minimalistic, so to speak.

You could just have one huge subwoofer to get below 20 Hz, since the wavelength is so long here, that one ultra-deep playing subwoofer would be enough, so long as the other 3 cover everything else.... still giving you smooth bass overall.

 

[levimax]

Ah. That makes perfect sense and affirms what I believed.

It also makes me wonder about a few things…

1) Will BassEQ mess up Dirac ART? Should I maybe implement BassEQ in software ahead of the receiver, instead of doing it in DSP ahead of the subwoofer? Maybe I need to rip and transcode the audio, or at least EQ it separately and re-sample it. I haven’t put much thought into this.

Any "speaker flattening" EQ that are part of the subwoofer should be done prior to ART. ART is not going to try to boost low bass below 20 Hz even with the 20 Hz high pass disabled, it knows better

2) What makes for a better time-domain 5Hz subwoofer: an Ultimax with massive bass boost or a Signature Series with slightly less EQ that starts at a higher frequency?

Any 5 Hz signal that may be reproduced by your proposed subs/ drivers is going to have less than meaningful SPL, massive distortion (most likely in 100's of percent), and massive group delay (literally hundreds of ms). I know you are looking at 5 Hz as an experiment but there are real negatives to try and real positives to rolling it off, the 2 biggest reasons being exciting mechanical resonances in the walls and even more so IM distortion which messes up reproducing meaningful frequencies in exchange for nothing really.

3) What’s better: using a limiter or a high pass to prevent over-excursion (or just using a lower power amp)?

Limiting excursion is better because mid-bass, where there is a lot of energy in most music, can require a lot of power. You don't want to limit what your speakers can do well in order to protect them from blowing up trying to do something they can't.

I assumed the Umtimax was unconditionally safe in the 4cuft enclosure. I was really hoping for an excursion simulation on that SS down to 1Hz. If I can let it run free without worry, that seems like the best solution. That was another reason for investigating that Dayton amp. It’s a couple hundred watts shy of the SS max power spec and should obviate any need for output limiting in that enclosure.

Large drivers in 4 cubic ft enclosures are "unconditionally safe" as long as you don't start trying to boost LF extension. Once you start boosting all bets are off and modeling will be your friend here as you will see how insane the numbers for excursion and power get when trying to boost below 20 Hz. Any commercial sub that uses DSP boost to lower extension uses a "protective" high pass, otherwise they would be out of business due to warrantee claims.

I’m also going to have to contact Dirac and find out if ART is going to add value to my system. If Dirac Live is going to truncate response below 20Hz and ART is also going to truncate response below 20Hz that’s bad. If it’s going to leave everything below 20Hz unEQ’d I can live with that, although it’s less than ideal. ART uses all the bass-capable channels so I don’t see how it can ignore frequencies below 20Hz.

ART is "part of" the DIRAC chain, you need DIRAC live and DLBC and ART in order to create and use ART corrections. You can disable the 20 Hz high pass in ART and the lower bass will come through but "uncorrected".