Been offered a "free" 18-inch sealed box subwoofer and not quite sure what to do with it . . .

[RetroStereo]

I've been offered a "free" 18-inch sealed box subwoofer and not quite sure what to do with it . . .
It was a flat-pack DIY Dayton Ultimax (the original one, not the II) from Parts express and it comes without an amplifier.
I'm guessing its 5 or 6 years old - it appears to be working properly.
Moreover, it's been turned on its face - woofer firing downwards - on 8-inch legs.
I know I don't need it (I have M-L Monolith IIIs and they don't really lack bass).

Current setup - Topping A90D -> Dahlquist DQ-LP1 (pass-thru) -> two McIntosh MC2255 (mono/parallel mode) -> ML xstat panels (for both L&R).
Dahlquist DQ-LP1 (bass out xo @ 125) -> McIntosh MC2255 (stereo mode) -> ML woofers (L&R).

But before I say "yes" and move this behemoth 140 miles, I'm wondering if this will work:
Cannibalize one of the mono-mode MC2255s to drive the 18-inch sub.
Reconfigure the other mono-mode MC2255 to stereo mode to drive the two xstat panels.
Cascade a 2nd DQ-LP1 (which I already have - purchased as "parts only" and got it fixed) connected to the center-channel (single sub) output of the 1st DQ-LP1.
Use the center channel output of the 2nd DQ-LP1 to drive the mono-mode MC2255 -> 18-inch Dayton
Set the xc for the 2nd DQ-LP1 somewhere between 60 & 80 ???

And then play Toccata & Fugue in D minor at 110 decibels.

Or, Just say, thanks, but no thanks.

 

[levimax]

I've been offered a "free" 18-inch sealed box subwoofer and not quite sure what to do with it . . .
It was a flat-pack DIY Dayton Ultimax (the original one, not the II) from Parts express and it comes without an amplifier.
I'm guessing its 5 or 6 years old - it appears to be working properly.
Moreover, it's been turned on its face - woofer firing downwards - on 8-inch legs.
I know I don't need it (I have M-L Monolith IIIs and they don't really lack bass).

Current setup - Topping A90D -> Dahlquist DQ-LP1 (pass-thru) -> two McIntosh MC2255 (mono/parallel mode) -> ML xstat panels (for both L&R).
Dahlquist DQ-LP1 (bass out xo @ 125) -> McIntosh MC2255 (stereo mode) -> ML woofers (L&R).

But before I say "yes" and move this behemoth 140 miles, I'm wondering if this will work:
Cannibalize one of the mono-mode MC2255s to drive the 18-inch sub.
Reconfigure the other mono-mode MC2255 to stereo mode to drive the two xstat panels.
Cascade a 2nd DQ-LP1 (which I already have - purchased as "parts only" and got it fixed) connected to the center-channel (single sub) output of the 1st DQ-LP1.
Use the center channel output of the 2nd DQ-LP1 to drive the mono-mode MC2255 -> 18-inch Dayton
Set the xc for the 2nd DQ-LP1 somewhere between 60 & 80 ???

And then play Toccata & Fugue in D minor at 110 decibels.

Or, Just say, thanks, but no thanks.

If you were going to do it I would not mess around with lowering the rest of the system headroom rather I would leave the system the same except add the extra crossover and set it low for ~45 Hz and pick up a crown or similar amp of around ~1,000 watts for the sub. You would probably not hear much difference until you played very loud. Not sure if it is worth it but it might be One other thing to consider is it doesn't look like anything in you system has the ability to add delays which is going to make sub integration quite difficult. All in all probably pass as it would take a lot of work to actually integrate the sub correctly and make an actual improvement and your main speakers have good LF response as it is.

 

[RetroStereo]

So far, I've done nothing to "improve" the environment my system plays in other than experiment with speaker placement. I plan to buy one of miniDSP's calibrated mics and EQ my room sometime in the near future (I'm about to get a knee replacement so it will be a few months off). I'm assuming that EQ and delay can work hand in hand; but what do I need to play around with delay?

Other than listening to friends' systems, I've essentially had a 45-year gap in my audiophile experience. I'm fairly computer literate; but I haven't applied it to my system yet. A LOT has changed. Perfectly awful speakers (well, relatively speaking) can be made to sound near flawless (within limits) with equalization. It's seriously amazing.

However small the improvement adding the Dayton sub may make in my system, it might be a fun learning experience. After all, I'm retired and pretending to be an audiophile again. So, aim me at some educational resources.

 

[levimax]

Different signal paths, and different distances from the speakers to the listening position and even different drivers will cause the signal to arrive at the listening position at different times. In order to properly integrate a sub you want all the signals arriving together so you need to delay the faster arriving speakers to match the slower arriving speakers. If you want to learn make sure you get a measurement MIC and REW and have at it. Good clean fun. Enjoy.

 

[mhardy6647]

If it's free, it's for me!

In all seriousness, one of the PE plate subwoofer amps with DSP will (should) give you all of the flexibility you'll need to do something useful with that subwoofer.

Full disclosure, and FWIW, having acquired a 2 x 15" subwoofer prototype, sans electronics, from a hifi friend and fellow traveler who does this stuff (audio component design) for a living -- that's what I did.

 

[mhardy6647]

If you want to learn make sure you get a measurement MIC and REW and have at it. Good clean fun. Enjoy.

Yes, this, too! Sorry, I forgot to mention that aspect.

REW is free and a decent, at least nominally calibrated mic isn't terribly expensive (at least the last time I looked!).

 

[levimax]

So far, I've done nothing to "improve" the environment my system plays in other than experiment with speaker placement. I plan to buy one of miniDSP's calibrated mics and EQ my room sometime in the near future (I'm about to get a knee replacement so it will be a few months off). I'm assuming that EQ and delay can work hand in hand; but what do I need to play around with delay?

Other than listening to friends' systems, I've essentially had a 45-year gap in my audiophile experience. I'm fairly computer literate; but I haven't applied it to my system yet. A LOT has changed. Perfectly awful speakers (well, relatively speaking) can be made to sound near flawless (within limits) with equalization. It's seriously amazing.

However small the improvement adding the Dayton sub may make in my system, it might be a fun learning experience. After all, I'm retired and pretending to be an audiophile again. So, aim me at some educational resources.

Here is a link on DSP set up written by a member here. A great place to start. https://drive.google.com/drive/folders/1VRndkoExTNFBOSqPTiiBmU67HlLUeiza?usp=drive_link Start with the first two on this list.

 

[RetroStereo]

Thanks to both of you.

So, after the initial several weeks recovering with my new knee, I'll order a calibrated mic from miniDSP, set up REW on my laptop, read some instructional PDFs and have fun playing with the new toys.

Edited to ask: Does it matter the the 18-inch Dayton sub has been turned on its face?

 

[Salt]

If it's free, it's for me!

In all seriousness, one of the PE plate subwoofer amps with DSP will (should) give you all of the flexibility you'll need to do something useful with that subwoofer.

Full disclosure, and FWIW, having acquired a 2 x 15" subwoofer prototype, sans electronics, from a hifi friend and fellow traveler who does this stuff (audio component design) for a living -- that's what I did.

Nice nipples ...

 

[mhardy6647]

Edited to ask: Does it matter the the 18-inch Dayton sub has been turned on its face?

In what sense? I.e., use or storage?
EDIT: In the latter case (Face-down storage): I'd assume "no", unless the surround is so huge it extends well past the front lip of the basket (EDIT: as, e.g., does the surround on the 15" Ciare subwoofer driver in the photos I posted). Some irreversible damage (e.g., compression or disfiguration) of the surround might result, but I'd think the likelihood is small.

Again... free!
In the worst case scenario, the surround could be replaced. I doubt that the spider (suspension at the back side of the cone) would be damaged.
This being said, I am far, far, far from an expert in subwoofery. So, I point back to... free.

 

[levimax]

Edited to ask: Does it matter the the 18-inch Dayton sub has been turned on its face?

Read up on "downward facing subs", there are some pros and cons and would probably be DSP's differently.

 

[mhardy6647]

Between the two of us we covered both possible meanings of "turned on its face".

 

[RetroStereo]

Again, thanks, guys.

The Dayton sub has been "face-planted" since initial construction - it was put to double duty as a coffee table that had to work for a living. The reason it's free is that the owner/builder has moved on to unearthly projects and his indulgent wife is redecorating to suit her non-audiophile tastes. That sub-table was never her cup of tea.

 

[mhardy6647]

That sub-table was never her cup of tea.

Along the lines of subwoofer-as-coffee-table... I shouldn't admit this publicly, but there is one of these in my basement.
In my defense, it was a dump transfer station swap pile find, and it's never been used as anything except a place upon which to store other basement junk, but... it's there.

 

[CherylJosie]

Any speaker that is not mounted horizontally will eventually develop a ‘set’ where the cone is displaced from center in its travel. It doesn’t matter how well the speaker is constructed. This ‘set’ will most dramatically affect the stiffer spider that is most responsible for centering the travel of the voice coil, as opposed to the surround that primarily stabilizes the edge of the woofer to prevent odd deformation cone resonant modes.

If the speaker is in service for long enough, the displacement will eventually cause distortion and dynamic range issues. It is most dangerous when the motor faces down because that makes the diaphragm sag toward the back of the magnet gap where the voice coil former is vulnerable to physically impacting the rear plate of the pole piece.

In practice, human hearing is very forgiving of distortion, especially when it is masked by other harmonic components. A downward-firing subwoofer is unlikely to ever produce audible artifacts owing solely to its sag, but it may develop dynamic range limitations. The first few cycles of a wave will re-center the cone in its travel because of the asymmetrical restoring force of the suspension as the excursion reaches its limits in both directions of travel, but the sense of transient impact will be affected by the initially asymmetrical range of travel, as will the transient distortion.

I wouldn’t be concerned about it unless you are building a high-octane system that you intend to keep in service for decades.

 

[CherylJosie]

Regarding the in-room response of downward-firing subwoofers, their principle advantage is that they are easy to place very close to a wall or corner while avoiding boundary interference cancellation. With the woofer physically centered in the bottom of the cabinet, it is optimally positioned for corner placement by design, without needing to pay attention to speaker orientation.

Larger subwoofers that fire forward may exhibit boundary interference with the wall behind them due to the large distance between the front of the cone and the wall. Many people aim these subwoofers sideways or rearward to reduce the impact of boundary interference.

 

[dpturner]

Along the lines of subwoofer-as-coffee-table... I shouldn't admit this publicly, but there is one of these in my basement.
In my defense, it was a dump transfer station swap pile find, and it's never been used as anything except a place upon which to store other basement junk, but... it's there.

View attachment 524507

I had that subwoofer! Matched well with my "tweeter arrays"! Ah, those carefree DAK days...

 

[RetroStereo]

Just to close this out, I accepted the gift, played with it a few weeks, and trashed it. While it worked initially, after it had been running in my system for a short while, it got scratchy sounding. I don't know if it was damaged from the stress of facing the floor all its life or if it had other problems. Regardless, I scrapped it.