[bellicon]

Since the speaker and room measurements are key to good outcome for the speakers, it is up to the customer to decide if they have time and would be capable to make multiple measurements. This would be required for any DSP based crossover and correction system for best use.

I'm willing to commit the time and effort do this but the big problem is deciding on the right horn/driver combo for my situation and specific goals. Please check out my thread. Any advice would be appreciated.
https://www.diyaudio.com/community/threads/horn-driver-combo-for-midwoofer-room-preferred-directivity-pattern.429264/

[HAL]

I am not familiar with horn drivers enough to comment on those products and designs.

Will leave that to more informed speaker designers. 

[Rusty Jefferson]

I'm willing to commit the time and effort do this but the big problem is deciding on the right horn/driver combo for my situation and specific goals. Please check out my thread. Any advice would be appreciated.
https://www.diyaudio.com/community/threads/horn-driver-combo-for-midwoofer-room-preferred-directivity-pattern.429264/

Man, that's quite the thread. I do enjoy the Joseph Crowe wood horns, so good on you there. I have two sets that I think may be more applicable to your apartment, as my living room is the same size and either one works well but larger would be a problem.

The first is the #1159. (https://youtu.be/f6S2V9D9_08?feature=shared)  He designed it as a typical ported 2 way but modified the design slightly for me to work with the SB Acoustics beryllium tweeter and Purifi 6.5" woofer that we installed in a sealed box. They are used with subwoofers. I prefer adjustable low bass because of Fletcher/Munson. I believe he will also make it as a small floorstanding speaker. The improvement from the controlled directivity compared to my previous speakers (more like what he demonstrates in that video) can't be overstated. The room is always the issue.

The other pair is the ES-800 one inch exit horns used with a very lightweight 12" Faital Pro mid-woofer and the same subs. A very compact compression driver based system that doesn't take up much more space than the #1159.

Either pair will play without audible distortion to levels well beyond what would be acceptable in your apartment and I think would be easier to implement in a room that size.  I do the asymmetrical diagonal setup. The ES-800 are more efficient and plays better with low power amplifiers. Mine use passive crossovers but the Danville is on my radar for going active. I have a friend using one with the latest AKM dacs and it sounds great.

[bellicon]

They are used with subwoofers. I prefer adjustable low bass because of Fletcher/Munson. I believe he will also make it as a small floorstanding speaker. The improvement from the controlled directivity compared to my previous speakers (more like what he demonstrates in that video) can't be overstated. The room is always the issue.

The other pair is the ES-800 one inch exit horns used with a very lightweight 12" Faital Pro mid-woofer and the same subs. A very compact compression driver based system that doesn't take up much more space than the #1159.

Either pair will play without audible distortion to levels well beyond what would be acceptable in your apartment and I think would be easier to implement in a room that size.  I do the asymmetrical diagonal setup. The ES-800 are more efficient and plays better with low power amplifiers. Mine use passive crossovers but the Danville is on my radar for going active. I have a friend using one with the latest AKM dacs and it sounds great.

Thanks for those offerings but I need to build a system that utilizes my midwoofers, as imperfectly conceived as they may be. https://josephcrowe.com/blogs/news/altec-416-8b-in-100l-sealed

Yes, everything about the room is critical to ultimate success, so much that I'm hoping to get more specific suggestions when I expect to soon get copies of the floor plans and blueprints of my apartment within the next two weeks. I suspect that it will end up being either a horn like Crowe's ES450 or possibly even the larger ES290. They offer more coverage below 5kHz than smaller horns https://cdn.shopify.com/s/files/1/0142/2848/8292/files/Screenshot_2023-10-14_170306_480x480.png?v=1697317415 but I'd hope that the narrowing coverage at high frequencies wouldn't make them sound like I'm wearing headphones and/or have sweetspot that's too much like head in vise, like the AH425 JMLC may sound, which otherwise is said to have superb imaging, and its 16" diameter may add some height with my 11 ft triangular ceiling. Have some driver ideas for a two-or three way system

The other end of the horn choosing spectrum would be the at least nowadays uncommon constant directivity horns, like the "mumped" Klipsch K510-though this knock off is minus the mumped mod https://www.ebay.com/itm/233808725468  OR something which I'd hope Troy Crowe, Weltersys and/or Cask05 might suggest. And a beryllium driver for a two-way system?

Regarding the power on/off transients which Kazoom found with DSPNexus https://www.audiocircle.com/index.php?topic=186956.msg1966210#msg1966210 ,
as this unit was at the top of my list at least for multisub (Rythmik F12) bass management and eventually for biamping a two or three way system, high level power on/off transients is the last thing beryllium compression drivers-far less my ears(!!!)-should be exposed. There are power sequencers one could use  https://gearspace.com/board/showpost.php?p=17133483&postcount=42, but shouldn't have to rely on for a DSP processor at this price point.

I was also concerned about the maximal output voltage vs. noise levels, as the DSPNexus balanced 4dbu outputs are much below that of the Merging Hapi's DA8 cards. https://www.merging.com/products/interfaces/specifications#a-k-d8-d-a-k-d8-d-p-option-card

Al Clark typically prefers answering DSPNexus related questions via phone rather then emails. And while a highly accomplished designer, I can't help but suspect a lack of forthrightness when he fails to reply to legitimate and important questions, and to the poster personally and at the original forum thread   
https://www.diyaudio.com/community/threads/exploring-high-end-component-upgrades-for-diy-active-speakers-with-dsp.415829/post-7761434 -and for that matter here as well.

 

 

[danvillesignal]

Hi Everyone,

I do prefer to have phone or video calls since I learn much more about your system and goals and I can answer a lot more questions as they come up.
I am not a writer - which is not a big surprise since I am an engineer.

I try to respond with minimal hyperbole and stick to factual statements.
My goal is to always have the dspNexus in the conversation of best sounding digital audio equipment. We are in a market of many opinions.

bellicon questions:

The dspNexus goes into a low power sleep mode that turns off the DSP, the data converters and the clocks, really most everything but the display. You can achieve a similar result with the mute control in that it will be dead quiet, but the unit will certainly stay on. The dspNexus runs warm. This is a natural byproduct of products with low noise floors since the circuits are low impedance which means high current requirements. The DSP is also fast which contributes.

We are releasing a 12V trigger - eight channel sequencer next month. Each 12V trigger output has individual programmable delay. You can use the Amp Ctrl of the dspNexus, a 12V trigger from other gear or set the unit to start from power up. We are just waiting for the enclosure metal to arrive.

The audio outputs of the dspNexus is very adjustable. It is not far lower than the Merging. They refer to +24dBu FS where +4dBu is the nominal level - Full scale would typically be about +22dB. You want to adjust the amplifier gain and sensitivities to be an optimal tradeoff between clipping and smallest signal. Usually this is a -12dB setting in the dspNexus.

Regards,

Al Clark

[bellicon]

Hi Everyone,

I do prefer to have phone or video calls since I learn much more about your system and goals and I can answer a lot more questions as they come up.
I am not a writer - which is not a big surprise since I am an engineer.

Weltersys, Cask05, Markw4, Lynn Olson, et al are certainly respected design engineers, and none of us have any trouble communicating in writing. Furthermore, all of them and other engineers I've done business with believe in the design and build quality of their products enough to state the truth about them in writing-which to me inspires great consumer confidence.

 

[bellicon]

The dspNexus goes into a low power sleep mode that turns off the DSP, the data converters and the clocks, really most everything but the display.

I didn't ask about this feature-nor did I know it existed, as I haven't  fully read the (revised) manual. But under what conditions is that sleep mode activated and deactivated? And upon wake up would there again be a loud pop heard through the speakers, like Kazoom complained about?
https://www.audiocircle.com/index.php?topic=186956.msg1966210#msg1966210

And seriously more so through high efficiency horn speakers, where hazardously high SPL transients could thereby occur?

[bellicon]

Hi Everyone,

I do prefer to have phone or video calls since I learn much more about your system and goals and I can answer a lot more questions as they come up.
I am not a writer - which is not a big surprise since I am an engineer.

I try to respond with minimal hyperbole and stick to factual statements.
My goal is to always have the dspNexus in the conversation of best sounding digital audio equipment. We are in a market of many opinions.

Regards,

Al Clark

Reiterating my concern about your apparent reluctance to affirm the performance of the DSPNexus versus competitive devices by doing so for community inspection in writing: Even more troubling is the failure to reply to Robh808's questions regarding the passive vs. DSPNexus active crossover shootout you held at Axpona this year. As Robh808 makes plainly evident, there's no proof that the shootout you held there was a 1:1 comparison.
https://www.diyaudio.com/community/threads/exploring-high-end-component-upgrades-for-diy-active-speakers-with-dsp.415829/post-7761434

In this game and at these price points only fools are content with phone chat assurances from product engineers-and also with telling questions from accomplished diyers which go ignored by these engineers.   

[HAL]

bellicon,
There are measurements online for the dspNexus 2/8 with the standard AK4493 DAC's:

https://audioxpress.com/article/outboard-dsp-danville-signal-dspnexus/

These were made before the upgrade AK4499EX DAC boards were available.

[danvillesignal]

When we do a passive to active comparison, we do not attempt to emulate the original crossover. What would be the point? Is the complaint that we don't deliberately cripple our system to make it fair?
I am not interested in that and frankly, I don't think our audience is either. We are showing how to make a good speaker much better by using modern technology.

Virtually all passive crossovers lack the complexity to properly EQ most loudspeakers and they can't adjust for time misalignment.

If someone emulates the original passive crossover with an active version, there are many advantages regardless of whether it is analog or DSP.

Here are a few:

1. Amplifiers have an easier load when driving speakers directly.
2. Intermodulation products between bands are eliminated if they aren't present to mix in the first place
3. Much improved damping which provides essentially a short to back emf of speakers, particularly woofers.
4. In a passive system, clipping caused by large low frequency signals always clips the higher frequency content.

A DSP now has enough processing power (sometimes too much) to allow sufficient complexity to tailor the response of the speaker. In the Magnepans, which use very simple first order filters, our crossover implementation is probably 25x more complex.
Using better capacitors and inductors doesn't change this situation.

If we assume that most content is digital already then in some ways, we are only discussing where we place the DACs. The dspNexus has very good DACs that are implemented skillfully. I have had a lot of practice doing this.

Sometimes I think we are in some kind of class war, I am not really interested in tweaking circuits that I designed 50 years ago. Maybe its time to move on.

Al Clark

[bellicon]

Sometimes I think we are in some kind of class war........
Al Clark

If there's some manner of warfare happening here I don't see it. Anyway, I'm not really disputing any of the claims you just made. It's merely what specific information you apparently chose not to provide, as I've repeatedly pointed out here.
 

Okay, one more time: 

I currently have no DAC save for a soundcard in my pc. The main speakers being built for me may not deliver sufficiently low bass response and output level with minimal distortion.
Thus, compensatory room analysis, cost effective treatment and use of three to four of my subwoofers are needed to realize ample and smooth low bass response. That, plus the need for two DAC channels to cross the main speakers passively-or four DAC channels to cross them actively-calls for an eight channel DAC solution.

I am presently refreshing my knowledge/memory of basic passive crossover design. And because I have no hands-on experience with any specific active analog or DSP crossover models, I need to rely on professional and user reviews, and credible would-be user reviews, to evaluate such products before purchase; especially complex and expensive ones like the DSPNexus.

Robh3606 is an accomplished DIYer and well known among several forums, including this one.
And he’s certainly an expert on designing and/or using passive and active crossovers.
https://www.diyaudio.com/community/search/2266573/?q=active+crossover&c[users]=Robh3606&o=relevance

So, when during a discussion with the designer of the DSPNexus, Robh3606 asked a basic and very important question, but which still remains here unanswered,
https://www.diyaudio.com/community/threads/exploring-high-end-component-upgrades-for-diy-active-speakers-with-dsp.415829/post-7761434 , as someone looking to buy an expensive DAC like this I find that very troubling on the part of the designer.

And if you were in my position, I’m sure you would too. 

 

 

[danvillesignal]

This is from Robh3606 via the link provided:

Ok but after looking at the video didn't you say you changed the speakers to measure flat on axis? You changed the crossover. If you altered the original voltage drive to the different panels that is obviously going to voice them differently. If that's the case it's not a 1 to 1 comparison.

Did I understand that right?

Rob 🙂

In my previous response, I stated that we used a much more complex crossover design.  I can tell you that stock Magnepans are not particularly flat. They have many good features that make them excellent candidates for improved crossovers.

If we are talking specifically about Rob's 1:1 question, then it was not an attempt to clone the existing crossover with digital filters. It's not that easy to do since Magnepan uses a series configuration that interacts with each driver. The midrange band also overlaps the tweeter, making it kind of a 2.5 way system. 

If you are interested in improving your system, then cloning a limited passive crossover is far less useful that designing a more optimal solution, one that is completely impractical or impossible with passive techniques.

At the time of the original post, the 1.7i demo (Axpona 2024) was EQed to be fairly flat. At Axpona 2025, it was adjusted a little whether we used subwoofers or not. It conformed a little more to the Harmon curve which causes a very slight roll off from flat.
Flat versus Harmon are both subjective choices and one of listener preference.

Rich was involved in both versions, and he may want to share more details.

There are youtube videos of the reaction of various reviewers.

Here is a 25 minute video from the Audiophile Junkie from Axpona 2025:

   Maggie's Taken to New Level Via DSP and Subs by Wendell Diller - Axpona 2025
   https://www.youtube.com/watch?v=K19zhdxDsAw

Best of Show Reports from Audiophile Junkie Team:

   Doug and Pete Share Their Axpona 2025 Favorites (starts about 5 minutes in)
   https://www.youtube.com/watch?v=rZWy7Xc3kto

At CAF last fall, we took a stock pair of Magnepan LRS speakers and just re EQ'd them, sometimes with subwoofers and sometimes by themselves. This is often a practical improvement that doesn't require bypassing the stock crossover. I prefer bypassing the passive crossover but this is not always an easy path.

Al Clark

[Solarflares]

For me, it’s like someone claiming to be building a hazy design, pipe-dream caravan in his shed, and then flaming Enzo Ferrari online because he wouldn’t answer how long the rear-suspension will last on a Dino 246GT when pulling this imaginary contraption.
 Then telling us all that your main worry isn’t the car - but the fragile China tea-set your mother gave you that you intend to keep in the imaginary caravan.
It’s all over the place. Both your head, and the stupid misplaced tea-set.
If you weren’t smoking so much of that stuff - you might actually be able to afford some decent speakers.
I’ve no doubt that both Hal and Al would successfully mitigate any design failings in your DIY abortions, but you really aren’t offering any respect, and frankly in your case, why should they - since you aren’t seeking real guidance and fresh knowledge. Instead just garnering for reactions, and playing to an audience.
Hal already did the right thing and politely bowed out, and if I was Al, I’d do the same.

[rhale64l7]

I am the op. And I really could care less about the question asked. To me it was very rude to come into someone's post and demand an answer to a post on another forum. The question doesn't even have a determination of sound quality. Even if he only slightly used the stock crossovers. I really don't see the big deal.
All I can say is I am not using a passive crossover at all in my speakers. And we have came up with a great solution for my spkrs. They sound absolutely fantastic. Never have they sounded better. And we went through all kinds of obstacles. None due to the DSP Nexus. XLR cabling problem. Threw off settings in the right channel.

[HAL]

Since this is rhale64I7's thread for his system, let's get it back on track.

I will try to split the thread so that they are stand alone and not mingled.  I believe the other questions have now been answered.

In the future if questions arise, please make a new thread. 

[HAL]

This is split from rhale64I7's thread for bellicon's answers.