Giant Custom Horn Systems - How they sound and issues with sonics

I definitely dream of one day building the ultimate system and room. I see what some of these crazy guys do with truly giant custom horn installations and they make me drool, but (like most of us) I've never had an opportunity to hear one of these crazy systems (see pics).

But I'm guessing at least a few of you have and others probably possess some theoretical engineering knowledge around the issues these giant horn systems might create, but I've never seen a thread that discusses the sonic pro's and con's of these systems.

Would love to hear some thoughts (even if it is just some pontificating on theory) regarding these types of installations. Let's discuss.
 

Comments

bonzo75

Member Sponsor
Feb 26, 2014
13,396
2,832
460
London
#41
After owning many different dynamic speakers over the years, a few years ago I commissioned Jeffrey Jackson to build me a 4-way horn system. No doubt horn systems take a little more effort to implement, but to me, the payoff was absolutely worth it. It has great tone, transparency, dynamics, effortlessness and jump factor that was discussed in another thread. Well designed horns, whether manufactured 60 years ago or today, do not suffer from the SQ issues that are so often attributed to them. I recommend hearing a pair if possible. I live in NJ and you are welcome to come listen.
Pics of the horns, please
 

morricab

Well-Known Member
Apr 25, 2014
3,989
797
198
Switzerland
#42
My horns system may not be giant, but it is quite big I guess. It was the optimum for what I wanted to achieve.

Yes, there are inherent problems like the distance between drivers the lobing it creates, and depth of the horns differing causing time alignment issues, horns colouring the sound etc. but they can all be solved. I know as I have solved them both measurably and aurally up to my standards, the information I have and the instruments I use to check them.

There are many things that a system like this dictates. One is space. I had to physically demolish walls and build a bigger room so that the sum of the drivers can be correctly heard. That meant I could not be too close to them while I had to be far to a back wall for acoustics purposes. The minimum distance for the exact aligned and correct distance for me was minimum 430cm away from the diaphragms. (this may be a problem for people and may even be prohibitive to have a system like this) My room is 10 meters deep, and 6meters wide for the most part, it gets wider further back.

Firstly time alignment. I have time aligned all my drivers using impulse response to my seating position, so I know and can test their alignment. There is no issue there, I can physically do this and measure it to confirm it. I have done this passively by physically aligning the drivers.

I have also used 1st order crossovers for the horn channels except for the tapped horn working below 40hz (3rd order) and the direct radiators working below 120hz (2nd order). There is a very important thing to do when using first order filters. For them to work you need to choose drivers and horns working together very very carefully and for their sums you need a flat impedance/response. It is impossible to have the ideal responses without any correction. So with the filter, I have also impedance correction on my crossovers. Otherwise a first order filter may not be (most likely) able to work against your driver/horn combination channels response deviations. It may try to filter a certain frequency while your driver/horn has a rising response there. A first order filter wont be able to do its job there unless it was flat to begin with.

Then there are certain limits to horns to sound good and physically work. One of them is, you can not push a horn below a certain limit. That lies between 1.5 to 2 times over its cutoff limit. Now, people claim to get it but what they generally do is, boost the driver there and actually get, not a horn loaded response, but a direct response from the driver. This not only also adds coloration but also distortion. The only place you can get away very close to cutoff is the midbass horn with a back chamber. Here you can reactance annul it and have a good response close to cf without audible problems.

Horns also colour the sound and "shout" when pushed too much to work wide-band. Generally a horn works for about 3 octaves and maybe a little more. You can get beyond it, byou can still measure flat but it will sound coloured and will beam. This again dictates what you can use as it dictates size and depth. That is why I could not use anything below 120hz to be horn loaded. If I had done it, I could not have aligned a horn that size both in height (the other channels would be too high, and upper end information which has narrower field would not be around my ear height) or it would not be aligned vertically which also sounds wrong to my ears and causes further phase and lobing anomalies. This dictated me that the biggest horn I could use can have a 1 meter diameter, hence my midbass. I also had different horn topologies at my place. I have found out that anything that plays above 60-80hz sound different in a bad way when the horn is folded and causes time alignment issues which can be heard. So I could not use horns and had to go with direct radiators.

All these are choices according to what is important to me to achieve what I think a good sound is. At the end, my choices dictated me my topology. 18hz to 40hz tapped horn, 40-120hz direct radiators, a 110hz cutoff tractrix with a 12" 285-2000 supravox modified with reactance annuling for 120-500hz, a 200hz tractrix with a 2" beryllium cd from 500 to 4500hz, a 1400hz JMLC horn with 1" beryllium cd for 4500-10000hz, and a fostex t500amkII for above that. These frequencies are not very exact as you can guess this is a first order system but these are the main band the channels are working.

So, for me, choosing the drivers very carefully, matching them with the right horns and using them in their intended bandwidths while having the right crossover altogether is very important. Also having a relatively flat impedance gets you a very good sound from the SET amp I use for my horns, which is great. I use solid states for my direct radiators and tapped horn.

The room is also very important, having the right homogenous decay and having a good response. I am sharing not only photos but also measurements as people tend to leave that generally. Here is my spl response and room decay (rt60). The SPL response was taken before room treatments were finished, the 70hz bump is gone and 100hz is much better but the rise towards 200hz but a little less pronounced. It is still there and can be seen to reflect in rt60 too. However as you can see, this is my room response from my listening point. It actually is +-4db for 18hz to 20hz which is for me a very good response. The decay in the room is also better than most of the studios I have been fortunate enough to be at!
Awesome stuff. Do you have impulse or step response measurments to assess the time coherence?
 

bgupton

New Member
Sep 24, 2014
109
3
0
San Francisco, CA
#43
After owning many different dynamic speakers over the years, a few years ago I commissioned Jeffrey Jackson to build me a 4-way horn system. No doubt horn systems take a little more effort to implement, but to me, the payoff was absolutely worth it. It has great tone, transparency, dynamics, effortlessness and jump factor that was discussed in another thread. Well designed horns, whether manufactured 60 years ago or today, do not suffer from the SQ issues that are so often attributed to them. I recommend hearing a pair if possible. I live in NJ and you are welcome to come listen.
Awesome! I’m friendly with Jeffrey and he is designing me something cool that hopefully I will have built locally by summer. Can you share pics and details on what he built for you?
 

kodomo

Well-Known Member
Apr 26, 2017
530
504
120
#44
Thanks @morricab
I had an impulse response done with rew with the aid of my old mobile recording setups soundcard (motu ultralite) using a loopback reference. I am very surprised that some people neglect to do this with their horn setups, as it is not hard to do and makes a lot of difference! It should be buried in the files somewhere, I will look it up. I have more than a few thousand different measurement files scattered around 3 computers. I had to go to some other forums that I have posted before to attach the spl response and room response graphics in my previous message :)

For the ones who are interested in the first order crossovers I have with impedance correction, here are the boards for my left channel, there 4 more for the right. Top left is the midbass, to its right is the one for the dual TAD 1601b woofers with 3 different cf points selectable according to the room. Down left is the 200hz tractrix and the one the down right is the tweeter and the cf 1400 upper mid. (for geeks, check out the vacuum bypass caps at the tweeter and upper mid board) These are done with the help of two very well informed German gentleman who also do this work for high end horn manufacturers.
 

Attachments

kodomo

Well-Known Member
Apr 26, 2017
530
504
120
#45
whole system

here is my system in its room
 

Attachments

morricab

Well-Known Member
Apr 25, 2014
3,989
797
198
Switzerland
#46
Thanks @morricab
I had an impulse response done with rew with the aid of my old mobile recording setups soundcard (motu ultralite) using a loopback reference. I am very surprised that some people neglect to do this with their horn setups, as it is not hard to do and makes a lot of difference! It should be buried in the files somewhere, I will look it up. I have more than a few thousand different measurement files scattered around 3 computers. I had to go to some other forums that I have posted before to attach the spl response and room response graphics in my previous message :)

For the ones who are interested in the first order crossovers I have with impedance correction, here are the boards for my left channel, there 4 more for the right. Top left is the midbass, to its right is the one for the dual TAD 1601b woofers with 3 different cf points selectable according to the room. Down left is the 200hz tractrix and the one the down right is the tweeter and the cf 1400 upper mid. (for geeks, check out the vacuum bypass caps at the tweeter and upper mid board) These are done with the help of two very well informed German gentleman who also do this work for high end horn manufacturers.
Very nice indeed! I am really curious about the impulse response...I have an affinity for speakers with time coherence. Did you get your horns from the Polish company Horns by Auto-Tech?
 

Walnut Horns

Active Member
May 11, 2015
65
19
38
#47
Here are photos of the horn system Jeffrey built for me. They are 105+ dB/W from 80Hz to 20 Khz, time aligned and phase coherent. The mid horns are field coil. The horns are driven with a two watt Type 50 tube amp and the compression loaded open baffle subs are crossed over and driven by a Class D amp with minimal dsp implemented on the subs only.


Horns & Stand.jpg
Sub Front.jpeg
Sub Rear.jpeg
 

bgupton

New Member
Sep 24, 2014
109
3
0
San Francisco, CA
#49
Here are photos of the horn system Jeffrey built for me. They are 105+ dB/W from 80Hz to 20 Khz, time aligned and phase coherent. The mid horns are field coil. The horns are driven with a two watt Type 50 tube amp and the compression loaded open baffle subs are crossed over and driven by a Class D amp with minimal dsp implemented on the subs only.


View attachment 39353
View attachment 39350
View attachment 39351
Did Jeffrey design the sub and amps too?
 

bgupton

New Member
Sep 24, 2014
109
3
0
San Francisco, CA
#52
Yes, Jeffrey designed and built the horns, subs, tube amps as well as my line stage and phono stage.
Here is what he designed for me. I LOVE the wooden horns he did for you and saw lots of pics of that speaker and their big brothers over the last few years as he was developing them. Would love to hear his speakers. Dude is mega talented.

Jeffrey Jackson Designed Speaker.jpg
 

spiritofmusic

Well-Known Member
Jun 13, 2013
10,572
1,810
358
E. England
#54
Can I ask what became of the big Wheel Fi horns?
I loved that video, but we’re talking 2015, and have seen nothing since.
And I’ve just tried logging on to Wheel-Fi.com, and the domain has expired.
 

Atmasphere

[Industry Expert]
May 4, 2010
876
95
180
St. Paul, MN
www.atma-sphere.com
#55
My speakers are made by Classic Audio Loudspeakers, the model T-3. The woofers are bass reflex, so the speaker is limited to 98 db 1 watt/1 meter, but they go down to 20Hz (dual TAD 15" drivers). The midrange is field coil powered and the tweeter is a TAD compression tweeter.

They image as well as anything I've heard, and all the imaging detail is coming from the horns. I don't mind the efficiency sacrifice, as any of our amps can easily drive the speaker and so I've got plenty of power (60 watts can literally shake the building) although my preamp can do pretty well without a power amp on them too.

Detail, nuance, speed, imaging, bandwidth- what's not to like??
 

bgupton

New Member
Sep 24, 2014
109
3
0
San Francisco, CA
#57
Can I ask what became of the big Wheel Fi horns?
I loved that video, but we’re talking 2015, and have seen nothing since.
And I’ve just tried logging on to Wheel-Fi.com, and the domain has expired.
He was partnered with the dude who founded Etsy on the WheelFi stuff, but my understanding is that they had a different vision for the way forward and agreed to separate. I got the impression that Jeffrey learned a ton with WheelFi, but wanted more independence. I think he retained the name, but I forget. I know he has another website, but I forget what it’s called now.
 

spiritofmusic

Well-Known Member
Jun 13, 2013
10,572
1,810
358
E. England
#58
I’m on the lookout potentially for a pr of horns as an end point set of speakers. I have a couple of contenders, but I’d have loved to have considered Wheel Fi. Too bad, that video really whetted many an audiophile appetite.
 

spiritofmusic

Well-Known Member
Jun 13, 2013
10,572
1,810
358
E. England
#60
I’ll drop him a message
Tbh I was a bit underwhelmed when I got no response to emails to Wheel Fi back in 2015. Maybe there’ll be more joy this time.
 

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