Speaker design based on large woofer

[Duke]

I use this (as an 80Hz-500Hz midbass in a 3-way + sub full active setup) based on your rec and it kicks so much ass it can't fit in a post. I use it in the Eminence "Small Sealed" design since I'm crossing to a sub anyway. Every system should have such a driver dedicated to midbass.

Yes, chief Eminence engineer Jerry McNutt did an absolutely outstanding job on the Kappalite motor design.

 

[levimax]

Yes, chief Eminence engineer Jerry McNutt did an absolutely outstanding job on the Kappalite motor design.

Does Eminence make any bad drivers (for their intended purpose)? Seems like they are on top of their game and have been for some time.

 

[Salt]

Are Visaton drivers available? They do have 12" and 15" PA drivers that might suit.

 

[ryanosaur]

What frequency range are you thinking of the 12" driver covering? I've never designed a loudspeaker in my life but using such a large driver to cover principally above 80 Hz seems like a strange choice...

This is where I am taking a page from @sigbergaudio and the Manta design. My plan is to run it from 80~320, roughly. Actual Subs will be used to do the heavier lifting below.

My intent on keeping the frequency bands which each Driver will handle so limited and away from the extremes of their capabilities is to aid in reducing compression and other distortion that can crop up, as well as maintaining very wide directivity throughout the whole Speaker. I don't know how many "good subwoofer" plots I've seen where the system is compressing pretty badly. One of the best charts I've ever seen is Cody's designs for Harbottle and Funk. Josh Ricci's Long Term Output Sweeps of Cody's design is pretty epic. Since I'm not custom crafting Drivers, the next best thing I can do is get some good Drivers and not push them to their extremes.

Also, in pushing for a more dynamic presentation [audio], the ability to move some air is a definite plus. It takes 4 6.5" Drivers to almost match a 12" Driver in surface area (Sd; roughly 480cm^2 compared to 530cm^2, respectively).

 

[TurtlePaul]

I feel like it is wastefully too conservative to crossover a Purifi 6.5" at 320 hz (it can do 40 hz) and a 12" woofer at 80 hz (it can do 25 hz). I would at least swap out the Purifi drivers which are tuned to go flat to 40 hz with massive xmax and instead use some of those popular SB or Seas drivers at 1/3 the price.

 

[DWPress]

This is where I am taking a page from @sigbergaudio and the Manta design. My plan is to run it from 80~320, roughly. Actual Subs will be used to do the heavier lifting below.

I like your design philosophy with plenty of frequency overlap happening between drivers. Digital XO allows for so much flexibility and experimentation when you're not locked into using the drivers natural limitations. I'm using 15" woofers that can extend to 30Hz but they have plenty of room to breathe crossed at 70 and 350Hz. In my space things sound and measure better letting 2 subs take care of the low end.

 

[JPA]

We seem to think alike. I'm in the latter stages of my DIY in-wall speaker build. Since I can't toe them in they must have very wide dispersion, and I have a bias toward high-ish sensitivity drivers. It's a 4-way + dual subwoofer design, with the main speakers mounted directly over the subs, so essentially a 5-way tower. The configuration is unusual -- upper and lower tweeters, dome midrange, and big woofer.

The drivers are:
Upper Tweeter: Raal 70-10D (92dB sensitivity) 8kHz - 20kHz
Lower Tweeter: Accuton C25-6-158 Cell (92.5dB sensitivity) 2kHz - 8kHz
Midrange: ATC SM75-150S (94dB sensitivity) 400Hz - 2kHz
Woofer: Scan-Speak 32W/4878T11 Revelator (94dB sensitivity) 80Hz - 400Hz
Subwoofers: 2 x JBL SUB1500 15" drivers in sealed boxes

I've only played test tones through the Scan-Speak woofers so far, but they sound excellent.

 

[ryanosaur]

Nice to see real-world-do-able targets, instead of wishing for the impossible!

For sealed box with a prosound woofer, you might consider the Faital 12RS430. 92 dB ballpark, very good motor and very well-behaved cone and suspension system:

https://faitalpro.com/en/products/LF_Loudspeakers/product_details/datasheet.php?id=151050115

In a vented box woofer, imo the Eminence Kappalite 3012LF performs way out of its league despite not having shorting rings in the motor. I used this woofer in numerous home audio speakers, with some response-shaping circuitry which would not be needed with your 320 Hz crossover target.

If you can find the sadly-discontinued 4-ohm version, even better, as it hits even harder. Based on its actual impedance curve it's more like a "5 or 6 ohm" woofer, but that category doesn't really exist, so it ended up being a "high 4-ohms woofer" whose voltage sensitivity was therefore lower than competing "4-ohm" woofers, so sadly it did not sell well enough and was discontinued.

Thank you, Duke. I already have the RS430 in my comparison list. I tend to lean toward Ported and thus the FX600 swept my interest along with it.

You bring up a good point, though, in considering sealed and I know it can have some good benefits. Especially since I'm not looking to push super low and needing that efficiency at lower output

I also looked at that Kappalite. I was a little concerned as I hadn't seen much to support it in the way I've seen everyone rave about the NSW line from Eminence. Its good to get your input on that.

 

[ryanosaur]

I feel like it is wastefully too conservative to crossover a Purifi 6.5" at 320 hz (it can do 40 hz) and a 12" woofer at 80 hz (it can do 25 hz). I would at least swap out the Purifi drivers which are tuned to go flat to 40 hz with massive xmax and instead use some of those popular SB or Seas drivers at 1/3 the price.

I do not disagree with you. At least not on every point. But yes, the cost of the Purifi Drivers against their proposed use is quite much. I know other Drivers can achieve the range I am looking to fill there, and if I can do that at 90% the performance and 1/3 the cost...

But, d@mmit man, I feel like I'm the only fool without a Purifi in his room, these days!

 

[ryanosaur]

We seem to think alike. I'm in the latter stages of my DIY in-wall speaker build. Since I can't toe them in they must have very wide dispersion, and I have a bias toward high-ish sensitivity drivers. It's a 4-way + dual subwoofer design, with the main speakers mounted directly over the subs, so essentially a 5-way tower. The configuration is unusual -- upper and lower tweeters, dome midrange, and big woofer.

The drivers are:
Upper Tweeter: Raal 70-10D (92dB sensitivity) 8kHz - 20kHz
Lower Tweeter: Accuton C25-6-158 Cell (92.5dB sensitivity) 2kHz - 8kHz
Midrange: ATC SM75-150S (94dB sensitivity) 400Hz - 2kHz
Woofer: Scan-Speak 32W/4878T11 Revelator (94dB sensitivity) 80Hz - 400Hz
Subwoofers: 2 x JBL SUB1500 15" drivers in sealed boxes

I've only played test tones through the Scan-Speak woofers so far, but they sound excellent.

Wow. I want to play with your budget! I do have 70-10s and 8" Revelators on my Phil3s. That is an outstanding combination. I would love to have an Accuton Mid in my life, too. If I could, I may well have considered the 70-20XR for my design, but they are much harder to come by, and the cost is not in my favor at 670Euros x3.

I heard a custom built, not for sale, all Accuton tower in a milled aluminum chassis. This was the last CA Audio Show in Oakland in '19, prior to Covid hitting. Absolutely stunning bit of work. The Mid and Treble clarity and detail was an absolute delight.

Regardless, would love to hear how your design works out!

 

[kemmler3D]

I do not disagree with you. At least not on every point. But yes, the cost of the Purifi Drivers against their proposed use is quite much. I know other Drivers can achieve the range I am looking to fill there, and if I can do that at 90% the performance and 1/3 the cost...

But, d@mmit man, I feel like I'm the only fool without a Purifi in his room, these days!

I tend to agree that running the Purifi in such a narrow band is a bit of a waste. They have very minimal distortion down to 200Hz and arguably lower, and they're clean as a whistle above that pretty much as high as you want to go, I think the limiting factor is beaming.

I think that in the band you're planning to use them, there are competitive drivers for probably half the money. It's almost a crime not to run the Purifi drivers at least down to 200hz.

I hate to suggest not using them because I think they're just plain awesome drivers, and subjective reports agree, but if you're not doing flat-out cost-no-object, and you're definitely doing a 4-way, they may not be a cost-efficient choice.

On the other hand, here's my pitch: Just copy the SPK16 design and add a 3rd way for bass instead of the PRs.

 

[sigbergaudio]

I feel like it is wastefully too conservative to crossover a Purifi 6.5" at 320 hz (it can do 40 hz) and a 12" woofer at 80 hz (it can do 25 hz). I would at least swap out the Purifi drivers which are tuned to go flat to 40 hz with massive xmax and instead use some of those popular SB or Seas drivers at 1/3 the price.

I'm not sure which Purifi driver is being discussed, but their 6.5" midrange driver only has +/-2.9mm linear xmax, it has no business reproducing 40hz.

And there are lots of 12" woofers not intended to reproduce 25hz.

@ryanosaur If you're running the 12" to 3-400hz, I'm still not sure why you need another two drivers (with different bands) between that and the tweeter. If you're very focused on the directivity, have you considered a waveguide for the tweeter?

And you should be looking at something that is designed for pure midrange use, with a very light cone.

Here is a good article about what makes a good midrange driver (there's actually not that many out there): https://jrkpost.medium.com/the-true-midrange-speaker-driver-1da12977f854

Maybe it's possible to feed the article to ChatGPT and have it search for compatible drivers for you.

 

[jayapple]

I've made my own before, and the speaker I use for gaming now is one I made myself.
In fact, you can achieve the parameters you want by making it yourself, but the cost will be higher than buying a ready-made one. Not to mention there are just too many DIY speaker models out there. You can't possibly buy them all to test and listen to. The success rate of random combinations is almost zero.

I considered buying a kit for a while, but kits are usually mid-range speakers and not cheap. You also have to make a professional enclosure yourself, and the cost of the enclosure will be much higher than the speaker kit. Even if you're lucky and the frequency response curve of the speaker you make is good, the problem of matching the tone of randomly selected speakers is a big issue. Each speaker has a different tone, and just looking at the frequency response curve is not enough.

In the end, I suggest that if you don't want to waste time and energy, buy a kit. If you really want to do it yourself, it's best to buy speakers from the same brand. The ones I'm making now are all from the same brand. When designers design speakers, they will prioritize matching their own brand's speakers, so the success rate will be higher, but it still depends on luck!

 

[jayapple]

By the way, the speaker I made myself is a three-way bookshelf speaker. First, it doesn't take up much space. Second, the three-way design is quite balanced.

I chose titanium diaphragm tweeters which have excellent extension and a strong sense of being detached from the cabinet, giving a feeling of being right in the center of the stage. The sound seems to come from right in front of me rather than from the speakers. The midrange is decent and stable without any fluctuations. The bass is made of super polyester material, which can produce powerful beats and also enhance the clarity of the mid and high frequencies.

In short, the sound quality is quite good, and all the speakers are from the same brand. However, if you only look at the frequency response curve, you might think there are many problems with this speaker. But in reality, it's not the case at all. The only issue is the transition between the mid and low frequencies, which is due to the crossover I made myself. You would never guess from the curve that the sound would be so excellent. I even sold two pairs.

 

[ryanosaur]

Not so random side question, if I may beg a little advice from any who care...

FWIW, I am still not ready to make a call on this, yet, but... I need to learn.

I am not well versed in any controlled directivity design. Admittedly, the bias of a few people who were influential during the development of my "taste" for very wide dispersion may be affecting my judgement.

A major concern is in horn loading a compression driver as I have seen countless statements about SQ coloration and "shouty" qualities being inherent in this design.

True, false, or it depends?

If I were to look at a Compression Tweeter, how do I avoid falling into any of the negative territory, or even, can I?

What do I look for in a Compression Tweeter for home audio use that will deliver in the most stringent aspects of very high SQ?

Thanks!

 

[NTK]

Quoting Dr Toole from this post. Apparently the superior performance of the M2 horn tweeter is due to technological advances in both the horn design (by Charles Spinkle) and compression driver deisgn (by Alex Voishvillo). The magic sauces are, unfortunately but predictably, covered by patents.

Horn Speakers - Is it me or.......

Who records stereo or multich with "1-mic 1-track 1-channel"??? That's called mono Indeed. It's very challenging to record mono thus. Like Dilbert and his database: https://dilbert.com/strip/1992-09-08

www.audiosciencereview.com

​

In my 50+ years of loudspeaker research I have heard and evaluated just about everything. In the early to middle years horns were, to my ears, easily recognizable by virtue of their audible "throat" colorations - heard within a very narrow high frequency beam. When I designed my first studio monitor loudspeaker in 1978 (described in Section 18.3.1 in the 3rd edition of my book) I evaluated numerous horns and drivers, ending up selecting a JBL "Smith" horn as being the most neutral sounding. It had almost no "throat". Over the years improvements were made to the directivity control of horns, but this feature persisted. Then a new wrinkle was introduced: short-throat horns. These were a change from the long-throw traditional sound reinforcement designs. For monitor speakers with less output demands and less restrictive directivity control, they seemed to sound better. Certainly they offered less opportunity for air non-linearity at high SPLs. In my experience the real breakthrough came with the JBL Professional M2, with a new horn and a new compression driver. The horn as can be seen is very shallow, with almost no throat in the classic sense. This combined with the new compression driver, which lacks the traditional large dome diaphragm and exhibits extended HF bandwidth was, to my ears, and others, exceptionally transparent. Since then it has held its own when compared to the best of the cone/dome designs. If it were not for the "industrial" appearance, I might well have had them in my recently renovated home theater. The more recent 7 series and 3 series monitor loudspeakers share the newly evolved design features. Consumer versions are appearing.​

There are other short-throat designs in the market now, and other designs I have not experienced, so perhaps it is time to retire some of the traditional biases.​

 

[Audionaut]

Beyond that, what really opened my eyes to some of this possibility was watching the Sigberg Audio Manta development.

Hello, first of all > may the speaker force be with you.

In my opinion, you haven’t mentioned the most important thing about Sigberg speakers: They all rely on a coaxial driver in the most musically critical frequency range.

Given the size of the speakers, it’s important to note that they should have high mechanical and thermal resilience in the bass range—a feature found in almost all high-quality PA speakers—as well as a high displacement volume, which can be calculated based on the two parameters of diaphragm area and maximum excursion.

I use—and I’ll mention this today in the Sigberg thread on Sentinel—the Beyma 18QLEX1600Fe with an extremely high BL value, which ensures very tight, extremely precise bass reproduction that I can easily adjust to my needs via DSP, since I can hardly overload the driver within its natural specifications in a living room setting. Neither mechanically nor electrically.

In practical terms, I would recommend an 8-inch coaxial speaker from B&C or Sica, paired with the BMS 12S330 or the BMS12S305.
And, trust me, if you use the two BMS chassis in a dual configuration per speaker starting at around 150 to 200 Hz, you won't need any additional bass support. Guaranteed

You can also go with a dual-driver setup and still end up with a very slim enclosure. Add a Hypex three-way module to that, and you’ve got a very good speaker system—provided you measure and tune it correctly, but with a little practice, you’ll be able to do that using REW and a measurement microphone.

Nothing beats a DIY speaker when you really love the way it sounds.

For example, you could use this one:

Sica 8CX2.5PL

8 Cx 2.5 PL P - Sica Loudspeakers

Coaxial Unit Code: Z005209P-8+8 8″ Nominal Diameter LF: 2.5″ Sandwich Voice Coil with Fiberglass Former and Aluminium Winding HF: 1.7" Voice Coil with Flat Aluminium Wire and Polyimide Dome Impedance: 8+8Ω Cloth Surround with Double Asymmetric Rolls Waterproof Cone Neodymium Magnet Circuit 100°...

sica.it

or this one,

8CXN64 8Ω - Coaxials - B&C Speakers

www.bcspeakers.com

though I haven’t tried it myself yet, but I think it’ll be good. (Have and had some B&C Coax - all very good)


You can actually buy from any Italian PA company without hesitation, even though there are always specialists for specific frequency ranges and designs.

But whether it’s B&C, Faital, RCF, Sica, or 18sound—they all build top-notch drivers.

Beyma from Spain builds some incredibly good drivers, but not consistently.

BMS is a German company with very good drivers that long held a monopoly on coaxial compression drivers. However, JBL and now B&C also offer coaxial compression drivers.

Oberton is a Bulgarian company that offers some excellent speakers in its lineup.

Generally speaking, a driver must always be a good match for the horn.
It’s not always possible to predict exactly how or if they’ll work together.
If you follow the driver and horn recommendations from established companies (for example, an 18sound driver recommended by 18sound for a specific 18sound horn), things usually go smoothly.
In my experience, horns that open up early tend to have little horn-like sound. You should avoid long horns.
If the horn’s mouth opening is the same size as the complementary woofer, it not only looks good, but it also typically performs well in tests, provided the crossover frequency has been chosen appropriately for the speaker’s radiation characteristics.

In conclusion: I don’t think you’re doing yourself any favors with a 5-step system. It’s very time-consuming, and it’s hard to ensure consistency across all levels.

But: I also know that sometimes you just have to stick with the things you’ve set your mind to.

Whatever you decide to do: Good luck!

 

[Audionaut]

P.S.

One idea I’ve been mulling over ever since I saw this horn

SB Audience :: XHYDE 290 NEW

www.sbaudience.com

is pairing it with the 18sound 10NMBA520 as a mid-bass driver.

 

[Duke]

... very wide dispersion...

4 way design featuring a 12" Woofer (higher sensitivity Pro Driver: FaitalPro, Beyma, or 18 Sound) or 2 10" Woofers (Satori Norex or ScanSpeak Discovery), 2 Purifi 6.5" Mid-woofers, 2 midrange drivers (undecided here, but possibly 2" domes... Morel and Visaton have some that look good). Mundorf ATM Tweeter.

I am not well versed in any controlled directivity design. Admittedly, the bias of a few people who were influential during the development of my "taste" for very wide dispersion may be affecting my judgement.

A major concern is in horn loading a compression driver as I have seen countless statements about SQ coloration and "shouty" qualities being inherent in this design.

I do not see a horn-loaded compression driver fitting in with your "wide dispersion" paradigm, so presumably you are exploring a different paradigm?

Imo the answer to your concern is, "it depends".

What do I look for in a Compression Tweeter for home audio use that will deliver in the most stringent aspects of very high SQ?

In my opinion: The horn or waveguide is what matters most, and you choose the compression driver after finding the best horn for your application, and that depends on what your midwoofer is... in other words, it's more like a "system design" thing rather than like just picking a tweeter.

I prefer for the radiation pattern of the horn or waveguide to match that of the midwoofer (at least in the horizontal plane) in the crossover region, and to remain essentially the same as high up as is feasible without using any diffraction (slots or kinks or sharp edges) to maintain pattern width. So something along similar lines to the SB Audience horn in @Audionaut's post above, although that horn's nominal 70-degree pattern width is arguably on the narrow side for pattern-matching in the crossover region.

DIY Sound Group's SEOS horns are good in my opinion, but at this time I am not aware of an off-the-shelf horn that "ticks all the boxes" for me. There was one twenty years ago but it's no longer available. So imo in practice it's a juggling of tradeoffs.

In practice, the horn or waveguide often ends up being about the same diameter (or width) as the midwoofer in a controlled directivity design. So if you have a midwoofer picked out, or at least a midwoofer size (or size ballpark) picked out, that would theoretically be a starting point.

As for compression driver choice once the horn or waveguide has been selected, I've had good luck with matching up the exit angle of the compression driver with the entry angle of the horn (thereby avoiding a discontinuity where they meet). Beyond that, I tend to prefer polymer diaphragms over Titanium diaphragms.

Ime horn or waveguide speakers tend to sound a bit "dry", presumably due to their relatively high direct-to-reflected sound ratios, so in my commercial designs I like to augment them with user-adjustable rear-firing drivers. Not suggesting you do so; just mentioning for the sake of completeness.

* * * *

I started out in speaker DIY in 1979. A pattern I've often seen goes something like this: An enthusiastic DIYer will have a great idea: Buy the best woofer and the best midrange and the best tweeter and put them in the best box and use the best crossover and... the results are often ultimately disappointing. Good system design beats a collection of expensive parts.

Also, in a big project, the most far-reaching decisions are the ones made earliest in the project, when you know the least. So the more you can learn and incorporate into those far-reaching initial decisions, the better.

So, kudos to you for asking questions up front!

 

[Audionaut]

It’s very time-consuming, and it’s hard to ensure consistency across all levels.

Automatic translation can sometimes be difficult or not very accurate. I’ll try again.
It is difficult to design a five-way loudspeaker that exhibits phase-accurate behavior across all five ways while also achieving coherent sound dispersion in both the vertical and horizontal planes.