Building a world-class Horn system for Small Rooms

After nearly 7 years, I think it's time to create a thread for my journey, in the hopes that it may inspire or help others with their own audiophile ambitions. My hypothesis was that world-class reproduction could be achieved in a small (~11'5" x 12'8" x 7'8) room. I think I have achieved it. I will post more photos and videos of playback over the next few months.

While my audiophile journey started many years before, the desire to create a world-class (almost) no holes barred system for my media room started with a visit to Oswald's Mill Audio (OMA) in Brooklyn and reading their (now removed) DIY meet summaries ("OMA Tastings"). If you have never heard a well-designed horn system close this window and go and find one, then come back. OMA has a beautiful showroom in Brooklyn. You should also listen to the Klipsch Jubilee at HiFi Loft in NYC (I have no affiliation and have never been). Be careful with horns from other manufacturers - not saying there aren't others, but it's more hit than miss.
 
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Interesting speaker build video:

Why aren’t more speaker cabinets made this way? I.e., by layering the wood. Must be cost, as this will undoubtedly make a more rigid cabinet.
The walls of my Classic Audio Loudspeakers are layered and are 3" thick. Internally braced as well, given the woofer is operating bass reflex.
 
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Good. As are the bass cabinets for my horns. This is the way Josh at ElectronLuv in Utah built them. It’s far more labor intensive with higher material cost to built the cabinets by layer.
 
Interesting speaker build video:

Why aren’t more speaker cabinets made this way? I.e., by layering the wood. Must be cost, as this will undoubtedly make a more rigid cabinet.
Did something similar years ago with walnut plywood I had sitting around. Very time consuming and I could imagine in a production environment as you said, very costly.

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Great thread Zeotrope. Your project loos wonderful. I would love to hear a video of your system. My old Magico Mini IIs had cabinets assembled from built up layers of birch ply. They were incredibly heavy and solid, and expensive to build.
 
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Thanks!
Recent feedback from the René LaFlamme at Nagra was that they don’t sound like horns - ie, zero coloration.
I’ll upload a recording at some point this year, in case anyone is curious.
Definitely interested to hear a video!
 
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Sure, I wanted the system to first be ideal for music (2-channel) reproduction; but also for movies. Music reproduction is a lot more demanding than movie reproduction, so starting with music first makes sense.
First, thanks for posting and showing your setup - beautiful horn speakers! What's the driver(s) and its size used in the bass horn, if I may ask?

On your quoted section above, not sure I agree. Movie sound reproduction can be quite a daunting task for a speaker with its wide dynamic range, complexity of sound field and the demand for proper dialogue reproduction. Not to mention the lowest octaves that can be a beast for many if not most typical, low efficiency hifi-speakers; the more you in "invest" in the power region on down to 20Hz and even below into infrasonics, it becomes clear how much you're potentially missing out on with movie sound here. I'm sure you know. I "only" have bass extension into the 20-25Hz region at full tilt (below which the response is high-passed for driver protection/theoretically lower distortion), albeit at 97dB sensitivity, and so I am missing out on the infrasonics of many movies. It's a compromise, and I chose to maintain a minimum of sensitivity, frequency bandwidth in the upper range, and keep size factor within an acceptable range.

Speaking for myself I too put music reproduction first, and this then "bleeds" into blessing the movie sound as well. No multi-channel approach here, no center channel (on that, not needing one, we definitely agree as well), just a pair of 2-way main speakers augmented with a pair of tapped horn subs. I'd much rather invest in getting the core basics of sound into place first, and then improve on that until an assessed potential is maxed out.
Most HT speakers are terrible for music reproduction. I'm a big believer in 'less is more' in terms of speakers for home theatres, especially in small rooms. There is usually no need for a center channel. Spending the same budget on fewer speakers and amps will also lead to better sound. Yes, I did get a Trinnov, but mainly because of its virtualization tech for speaker placement and because you can use an external DAC.
Generally agree on the above.
No DSP - other than for subs, I think DSP is a band-aid that is best avoided. Why? Because you're converting A to D to A, two extra conversions which definitely reduce quality. Get it right with room treatment, seating positions, and the right equipment instead of using DSP. For the high-end, anyway, DSP should be avoided.
When you single out the A/D/A conversion processes for being "accountable" for the reduction in sound quality when going the DSP route, is that a qualified guess, or..? Many seem to point to this area of DSP as the weak spot, but at the same time they avoid getting into how a passive crossover between the amp and drivers is not ideal either - to say the least.

Is it the lesser evil then, passive crossovers? From my chair: no, just the opposite. Going active with horns via DSP (because DSP can also be used for crossover duties only, sans digital room correction) is the natural choice for me, as it offers a range of added possibilities with steeper slopes, more accurate notch placements and the opportunity of delay adjustments in particular. Actively you're more effectively maxing out the potential of your amps with better driver control, as well as amp and driver section independency, etc.
 
Thanks for the comments @Jägerst!
The midbass drivers are Supravox field coil 285-2000EXC.
I agree with the need for a subwoofer for movies. What I have been doing is routing the LFE channel to the main L-R channels, because I have an active sub on these channels and I know they can play down to 20Hz. BUT - what I have found is that it’s easy to overload the L-R channels and clip the signal. If you have the L-R channel levels set so that you can play 105dB without clipping (the Dolby standard is 85db + 20dB headroom; and this is a good target for music as well) — but then you add another 20dB or more from the LFE track, you can easily clip the main channels. So even a low cost sub is better than no sub, even if your main channels can play the low frequencies. I will hopefully get a sub in the next few weeks; I’ve been waiting for Funk Audio to built it for over a year.

Regarding DSP: my philosophy (and no, I did not compare to the other approach) is to be a ‘purist’ and keep the signal analog if the source is analog. If the source is digital, adding DSP is totally fine; but if I have an analog source, I don’t want to convert it to D and then back to A.
 
Did you try different horn profiles before settling on the multi-sided conical for the mid range? I've built and listened to a few of those after being inspired by the Oswald Mills write ups. I know the guy who designed those is really against any use of a round over or any kind of curvature in a horn for hifi use in the midrange, and I know he has extensive experience with horn design. I still don't feel I understand his argument. A big round-over on the mouth makes the whole horn bigger and more expensive but it also smooths out the on and off axis response considerably due to significantly lower diffraction. The ones I built all demonstrated the mouth diffraction. I will say they sounded good even though the response looked relatively messy compared to other horn flares with round-overs.

Ultimately they used a round-over for the Fleetwood DeVille, but mounted in a baffle > not optimal.
 
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[* After calling out OMA on why they claim that a ~90dB efficient speaker can be adequately powered by a ~2W amp (they can't!), Weiss told me to get lost. And that was at the start of a journey in which I spent close to $500K (speakers alone were a lot less). I just had to share as it's too funny and it brings to mind that scene in Pretty Woman.]

Weiss also stuck to the DeVille's claimed 94 dB sensitivity, after Atkinson (correctly) pointed out that it's actually lower.
Apparently, marketing BS goes a long way.

This is the sensitivity of the woofer used in the DeVille @2.83V (best case):

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Even in Weiss' (fantasy) universe, there's no way this woofer can be adequately powered by a ~2W amp.
Not going to happen with a woofer whose η0 amounts to 0.9%. The calculated efficiency is actually slightly lower and the calculated sensitivity is 91.39 dB.
This applies to the naked driver, i.e. before additional losses due to, among other things, passive crossover components.
 
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Zeotrope, if at sometime in the future you are blessed with a more commodious listening room I suggest that you acquire horn loaded subwoofers to complement your beautiful horns. Nothing blends more seamlessly with horns than other horns.
 
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