3 way active with real punch.. which way would you go.? Pro driver or .?

[dped90]

I'm very impressed by Audiohorn's approach to horn design, though I'm still plowing through this. https://audiohorn.net/sciences/critical-distance/

Meanwhile, what are the criteria for choosing between the X-40 horn and the biradial horn?

Audiohorn recommends specific drivers to use with these horns. For Biradial: 18Sound ND3T-16, Faital HF144, (JBL 2450SL (virtual uobtainium)
For X-40: 18Sound ND3N, FaitalPRO HF1440/1460, 18Sound 4015, (JBL 2450SL (virtual uobtainium)

But might either of these drivers work well with one or both of those horns? https://www.usspeaker.com/radian 745neoBepb-1.htm
https://www.usspeaker.com/radian 760neoBepb-1.htm

Any issues with their phase plug or diaphragm design or crossover frequencies?

My midwoofers are these which Troy Crowe tested.

Altec 416-8B in 100L Sealed

In this blog post I test the Altec 416-8B in a 100L sealed enclosure. Testing was done outdoors for the frequency response and then brought indoors for the distortion testing. The woofers are new from Great Planes Audio. A customer has sent me the finished cabinets with drivers to integrate...

josephcrowe.com

 

[Heinrich]

I'm very impressed by Audiohorn's approach to horn design, though I'm still plowing through this. https://audiohorn.net/sciences/critical-distance/

Meanwhile, what are the criteria for choosing between the X-40 horn and the biradial horn?

Audiohorn recommends specific drivers to use with these horns. For Biradial: 18Sound ND3T-16, Faital HF144, (JBL 2450SL (virtual uobtainium)
For X-40: 18Sound ND3N, FaitalPRO HF1440/1460, 18Sound 4015, (JBL 2450SL (virtual uobtainium)

But might either of these drivers work well with one or both of those horns? https://www.usspeaker.com/radian 745neoBepb-1.htm
https://www.usspeaker.com/radian 760neoBepb-1.htm

Any issues with their phase plug or diaphragm design or crossover frequencies?

My midwoofers are these which Troy Crowe tested.

Altec 416-8B in 100L Sealed

In this blog post I test the Altec 416-8B in a 100L sealed enclosure. Testing was done outdoors for the frequency response and then brought indoors for the distortion testing. The woofers are new from Great Planes Audio. A customer has sent me the finished cabinets with drivers to integrate...

josephcrowe.com

Can't resist; the driver shows the typical problem with the surround at about 600Hz:

https://cdn.shopify.com/s/files/1/0142/2848/8292/files/Altec_416-8B_100L_Sealed_95dB_50Hz_and_above_480x480.png?v=1695411148

On the horn drivers i would suggest that all modern-ish types will provide a plane wavefront, which is what AudioHorns wants.

 

[dped90]

Can't resist; the driver shows the typical problem with the surround at about 600Hz:
https://cdn.shopify.com/s/files/1/0..._95dB_50Hz_and_above_480x480.png?v=1695411148 [/QUOTE]

How audible might the IM distortion be at 600Hz at ~ 75 to 80db from 11 ft?

On the horn drivers i would suggest that all modern-ish types will provide a plane wavefront, which is what AudioHorns wants.

My knowledge is limited which is why Troy Crowe is using some of the parts I have to build speakers, though I am open to using other parts. But what do you mean by a "plane wavefront"?

Why do Audiohorns require this? And why wouldn't the Radian 745neoBe driver be unable to provide it?

 

[Heinrich]

How audible might the IM distortion be at 600Hz at ~ 75 to 80db from 11 ft?

Not much, don't worry. It was that it just reminded me that the surround is a forgotten problem, that Purify solved with a presumably ugly shape ;-)

On plane wavefront, that is simply how horns work. It is the expected interconnect between horn designers and driver designers. Most probably the Radians do the best they can to some success, as said. A test will tell.

 

[dped90]

Thanks, as I was worried because if I don't used these midwoofers with one of those two Audiohorns I will be using it with this combo:
https://josephcrowe.com/products/3d-cad-files-horn-no-1994-es450-biradial-for-jbl-2446-2-throat
16 ohm version of this midrange https://bcspeakers.com/en/products/hf-driver/archive/2/8/DCM50
which was tested here. https://josephcrowe.com/blogs/news/es-450-biradial-no-2143?_pos=6&_sid=f5deb566e&_ss=r
And this tweeter. https://josephcrowe.com/products/3d...-for-fostex-t925a?_pos=3&_sid=adb9fa53f&_ss=r

Actually, during our diyAudio.com chats, Nicolas pointed out the Altec 416-8B's distortion, though I think it was 3rd harmonic not the IM.

He said this active filter would fix it. https://audiohorn.net/sciences/speaker-break-up/
It's a combo passive + active, from that article. The breakup generates H3 distortion (1800/3 ->600hz in your case). It solves with back electromotive force.

But the above Joseph Crowe horn combo and my midwoofers would be used with the passive crossovers he builds for them, at least for several months.

This week was my first attempt at learning DSP software to design crossovers for biamping speakers using either of these horns. https://audiohorn.net/x-shape-horn/
https://audiohorn.net/next-gen-bi-radial-horn/

I got through these two sessions with understanding at least 80% of what was discussed.

What's also cool is that since all of my audio sources are outputted via USB I can learn how to use Audio Weaver to improve performance of the passive crossovers of my existing speakers.

So for biamping my main speakers and for integrating my four subs https://www.rythmikaudio.com/F12.html I've narrowed the processor down to the DSP-Nexus or the Merging HAPI. The former is likely way more home user friendly; no wonder it was a hit at the Axpona show.

But my chief concern is sound quality, or perhaps more precisely sound signature. The DSP-Nexus uses the AKM 4495 DAC. Danville's Al Clark said "If we thought there were better DACs, we would use them instead." https://danvillesignal.com/dspnexus-dsp-audio-processor , assuming Burr-Brown (TI) or other Analog Devices DAC chips were considered.

But what of AKM "Velvet Sound" DACs”? https://velvetsound.akm.com/us/en/ compare to standalone DACs you may have heard? Might it be akin to the sound of the Tripathi Class-T amp? https://en.wikipedia.org/wiki/Class-T_amplifier

I remember Pano saying that he used to sell those chip amps at audio shows and where people hearing them would end up loving them as much or more than their 300B SET amps. https://www.diyaudio.com/community/t...1#post-7666758

While impressive, wouldn't a more "neutral" sounding DAC be preferable for a DSP processor?

My only experience with AKM DACs is the AK4490EQ in my Pioneer LX500 BD player. And perhaps like a 300B tube amp I think it sort of does have a kind of relaxed sound compared to the more neutral sounding ESS SABRE32 ES9018 DAC in my Oppo BDP95 BD player.

Another great thread. https://forum.audiogon.com/discussions/dsp-active-crossover I see Danville’s Dan Clark and lewinskiho1 from
https://www.diyaudio.com/community/...eh-synergy-project.409866/page-7#post-7663781

ricevs mentions that some miniDSP models have digital outputs so you could use your own DAC. But if one has an expensive DAC (e.g. Halo May DAC) you would need to buy a second one for speaker biamping. And even then they would have to be super accurately clocked together. Doesn’t seem like an attractive solution.

Otherwise, perhaps the best alternative might be the Merging HAPI using Audio Weaver for all DSP solutions for speakers and subwoofers?

 

[Heinrich]

... Nicolas pointed out the Altec 416-8B's distortion, though I think it was 3rd harmonic not the IM.

All your future plans are obviously beyond my paygrade, so I'm going to comment on only a few points.

It is the IM, that doesn't have to do with cone breakup at 1.8k which latter gives rise to 3rd harmonic.

He said this active filter would fix it. https://audiohorn.net/sciences/speaker-break-up/

Nope.

It's a combo passive + active, from that article. The breakup generates H3 distortion (1800/3 ->600hz in your case). It solves with back electromotive force.

His explanations are a bit misleading. He conveys, that the cone's movement would generate a back e/m force etc. That is not the point. Purify issued a little paper on the topic also. Still the cone breakup amplifies the radiation of distortion components generated in the motor. That makes it stand out in the plots. But the e/m force is generated when playing the 600Hz. Necessarily the 1.8kHz component has to run a current through the motor to drive the cone at that frequency. Prevent the current, blocked by the air coil, and the drive is gone, and so the distortion.

But the above Joseph Crowe horn combo ...

As said, that's all well above my budget, hence I cannot comment due to lacking experience.

 

[speedbad]

AudioHorn doesn't require specific drivers, but recommends a few that have been thoroughly tested and are top-tier performers.

All compression drivers, without exception, provide a plane wavefront—except, of course, in their breakup region. Without plane wavefront the horn' profile is not respected/followed.

Back EMF has been well understood for quite some time. Your woofer doesn't need to "pass" through the breakup range for it to become relevant. For example, a 500 Hz third harmonic distortion (H3) creates a mechanical component at 1500 Hz—even if you're filtering at 600 Hz. That's why increasing the impedance at 1500 Hz to block this unwanted energy works so effectively.

So yes, in active filtering setups, using an air-core inductor or a notch filter for breackup back EMF traitement —as described in the article—can be very effective.

 

[JohnnyNG]

B&C 12NBX100, Eminence 3012LF. The latter has a 3" voice (instead of 4") and no shorting rings, but the designer (Jerry McNutt of Eminence) did a superb job with the motor geometry, and imo this very reasonably-priced woofer punches well above its weight class.

Appreciated, sir. The 3012LF looks pretty perfect in a ~1ft^3 sealed box. The idea is to use a pair crossed (actively) between a single *sub* woofer (<80Hz) and the mains (>300Hz). Thinking of placing one below each main.

Thanks again for the 3012LF recommendation, Duke. I wound up doing exactly this under my Revel M106 and am happy with the way they're performing.

 

[Duke]

Thanks again for the 3012LF recommendation, Duke. I wound up doing exactly this under my Revel M106 and am happy with the way they're performing.

Very nice! Thanks for letting me know. I've used the Eminence 3012LF in multiple home audio speakers as well as multiple bass guitar speakers.

What is the finish on the enclosure for the 3012LF, if you don't mind?

If you want to hide the bright unfinished metal around the perimeter of the 3012LF's frame, two coats with a black Sharpie works great. Might have to remove the woofers to do so.

 

[JohnnyNG]

Very nice! Thanks for letting me know. I've used the Eminence 3012LF in multiple home audio speakers as well as multiple bass guitar speakers.

What is the finish on the enclosure for the 3012LF, if you don't mind?

If you want to hide the bright unfinished metal around the perimeter of the 3012LF's frame, two coats with a black Sharpie works great. Might have to remove the woofers to do so.

Thanks, and I appreciate the Sharpie tip!

The finish is DuraTex roller grade applied with their 3" textured roller. First time I've used it but won't be the last - very easy to apply and clean up. The color/texture match with the 3012LF front gasket is purely coincidental.