Paul McGowan on Horn Loudspeakers

[microstrip]

(...) That is to say: one doesn't just freely compensate low efficiency in speakers with more amp power, as it comes with a price: heat build-up and eventually thermal compression, or (and I believe this term was "coined" by Mr. @Duke LeJeune): thermal modulation, which relates to the dulling of transient behavior due to "peak heat-up" as the perhaps more prevalent and audible side effect vs. compression that ends up frying the VC's and XO components due to excessive heat. (...)

Thermal modulation exists and is well studied - it is extremely easy to measure, as it implies an electrical change in the resistance of the speaker coil. As far as I see it, it is only relevant at high powers, used by professionals at disco levels or open spaces - I think it is not an issue for people listening at the commonly used levels that do not affect our hearing ability in an irreversible way.

Do you have any electrical measurements in real speakers that show otherwise? Many speakers show compression at high level that is due to mechanical or magnetic speaker non-linearity, that can easily be confused with thermal modulation.

 

[Duke LeJeune]

Thermal modulation exists and is well studied - it is extremely easy to measure, as it implies an electrical change in the resistance of the speaker coil. As far as I see it, it is only relevant at high powers, used by professionals at disco levels or open spaces - I think it is not an issue for people listening at the commonly used levels that do not affect our hearing ability in an irreversible way.

Could you be thinking of thermal compression?

A few years ago I had a conversation with Floyd Toole about thermal modulation, the short-time-constant cousin of thermal compression. He said that thermal modulation is a real effect which he has often observed but it has not been adequately studied, and was unlikely to be adequately studied as the funding for that sort of thing would have to come from the prosound side, where currently there is insufficient interest.

 

[microstrip]

Could you be thinking of thermal compression?

A few years ago I had a conversation with Floyd Toole about thermal modulation, the short-time-constant cousin of thermal compression. He said that thermal modulation is a real effect which he has often observed but it has not been adequately studied, and was unlikely to be adequately studied as the funding for that sort of thing would have to come from the prosound side, where currently there is insufficient interest.

As far as I know, the short time is not problem using digital techniques. Even using analog techniques - long ago I read a french article where it was studied using null techniques - in two equal speakers one had the tweeter replaced with a network using materials of zero temperature coefficient and the current signals measured in the low ohm series high power resistors were subtracted. The speakers were driven with music with high transients and at normal levels differences were less than 65 dB.

IMO if thermal modulation was really an issue someone in the high efficiency speaker community would have successfully shown it. It is commonly addressed - we even have patents on the subject https://patents.google.com/patent/US20040156525A1/en

BTW Floyd Toole at Harman probably also had to deal with high power speakers playing at 125 dB peaks!

 

[Duke LeJeune]

BTW Floyd Toole at Harman probably also had to deal with high power speakers playing at 125 dB peaks!

I found Floyd Toole's reply to me, and here is the relevant part:

"The audibility of power compression in its many variations probably could use some more research to define what is audible and what is tolerable. The magnet heating that you describe is important in pro audio sound reinforcement systems where the loudspeakers are required to work at or close to their design limits for long periods. Such heating and cooling has a very long time constant. This is not the case in most home systems. Although the modification of motor strength through magnet heating is a factor, most of the audible effects are from voice coil heating, which has a much shorter time constant. I just saw a test of a high-end audiophile speaker that in going from an average level of 70 dB (loud conversation, background music) to 90 dB (a moderate crescendo, or foreground rock listening) lost about 4 dB in output over about 3 octaves in the mid-high-frequency range. It became a different loudspeaker at different listening levels." [emphasis mine]

 

[the sound of Tao]

I can’t get through Paul’s videos for the most part
he dumbs in down and fills it with misconceptions. now he does have some good honest comments truly honest be it correct or not
ill Give him that

I saw the insides of a pair of his BHK 250 mono amps that were prematurely rusting perhaps he should stop making videos and spend just a bit more of his time on quality control …

 

[Kingrex]

My brain went more to the concept of your brain adjusting to the sound of a.horn. Power/efficiency blablaa.


Horns do take time to warm up to. A box speaker person sitting in front of horns may very well be put off. They play dramatically different. The first time I heard horns it was an adjustment. The first time I heard Magnepan, it was different. The horns much more so. The second and 3rd. Time I heard the horn I understood more what was coming and could digest it better. It was the 3rd or 4th time I teally began to appreciate it.

 

[PeterA]

My brain went more to the concept of your brain adjusting to the sound of a.horn. Power/efficiency blablaa.


Horns do take time to warm up to. A box speaker person sitting in front of horns may very well be put off. They play dramatically different. The first time I heard horns it was an adjustment. The first time I heard Magnepan, it was different. The horns much more so. The second and 3rd. Time I heard the horn I understood more what was coming and could digest it better. It was the 3rd or 4th time I teally began to appreciate it.

Rex, you make it sound like a universal truism. I heard a JBL Everest and liked it. Then I heard the Bionor and thought it was the best speaker I ever heard. No 3rd or 4th time necessary at all. I loved my Vitavox the first time too. I suppose it depends on the horn and rest of the system.

 

[dcathro]

My brain went more to the concept of your brain adjusting to the sound of a.horn. Power/efficiency blablaa.


Horns do take time to warm up to. A box speaker person sitting in front of horns may very well be put off. They play dramatically different. The first time I heard horns it was an adjustment. The first time I heard Magnepan, it was different. The horns much more so. The second and 3rd. Time I heard the horn I understood more what was coming and could digest it better. It was the 3rd or 4th time I teally began to appreciate it.

For me, that depends on how much horn we are talking about.

Giant horns such as the big Avantgardes always sound a little odd to me, but smaller/shorter horns not so much.

A friend just got a pair of Volti Rival SEs, and I was immediately impressed with both their tonality and speed.

 

[microstrip]

I found Floyd Toole's reply to me, and here is the relevant part:

"The audibility of power compression in its many variations probably could use some more research to define what is audible and what is tolerable. The magnet heating that you describe is important in pro audio sound reinforcement systems where the loudspeakers are required to work at or close to their design limits for long periods. Such heating and cooling has a very long time constant. This is not the case in most home systems. Although the modification of motor strength through magnet heating is a factor, most of the audible effects are from voice coil heating, which has a much shorter time constant. I just saw a test of a high-end audiophile speaker that in going from an average level of 70 dB (loud conversation, background music) to 90 dB (a moderate crescendo, or foreground rock listening) lost about 4 dB in output over about 3 octaves in the mid-high-frequency range. It became a different loudspeaker at different listening levels." [emphasis mine]

I have seen worst - the Stereo german magazine measures it routinely - but this looks like power compression, not transient modulation as you refer. Anyway these are poor designs - sometimes using a single tweeter abusively crossed at 6dB a low frequency - such poor designs exist with any type of speaker. Sorry but using such anonymous type of argument does not lead us anyway. My point is simply that when existing these anomalies are easily measured without rocket science.

Voice coil heating is well studied by manufacturers and easily measured. Dynaudio is known to shows graphs of power compression in their datasheets.

 

[tima]

Horns do take time to warm up to. A box speaker person sitting in front of horns may very well be put off. They play dramatically different.

Perhaps -- it may depend on your interest or focus While I see what is before me, if a system presents music realistically I respond without first thinking about the technology. Sometimes I look back to ask myself the question "what was my very first reaction?" Upon hearing something new.

 

[caesar]

Interesting discussion, but who cares about what Paul McGowan says? His DSD DAC is atrocious, and he is trying to sell to the market segment just above the mid-fi crowd.

 

[Kingrex]

I should not have said, warm up too. I should have said somerhing such as, horns in general, present in a way not at all like a sealed box or ported driver speaker. You might like it right away. But "I Think", most peoples first time hearing them are tilting their head a bit as they digeat it. I don't believe the average person understands them all at once with a listen to 1 song. Or 5 songs. Or 10.
And it helps to walk away, digest and come back. Our brains seem to need data points just like a computer to absorb information and make a full appreciation of what we are hearing. .

And from there a decision about whether we like it or not.

 

[KeithR]

did you hear Leif’s videos with 7 watts of 300b playing Beethoven 9th and black sabbath? Or Altec with 3.5 watts playing black sabbath?

I think it’s funny Black Sabbath is talked about on this forum as its 50 years old now. Why can’t we talk about modern rock here or something with far more influence

 

[Kingrex]

I think it’s funny Black Sabbath is talked about on this forum as its 50 years old now. Why can’t we talk about modern rock here or something with far more influence

What?????? I think Black Sabbath had a profound influence on many later musicians. And some.of it kicks @$$

 

[Folsom]

To answer @Ron Resnick ’s question. Yes, historically dependable watts were around 15-20wpc max. You could get a lot of use in that range.

I don’t look to Paul for info. For a lot of people it’s probably fine but he’s wrong sometimes, sometimes in big ways.

 

[the sound of Tao]

For me, that depends on how much horn we are talking about.

Giant horns such as the big Avantgardes always sound a little odd to me, but smaller/shorter horns not so much.

A friend just got a pair of Volti Rival SEs, and I was immediately impressed with both their tonality and speed.

Though it’s easy for some to be impressed by a good horn and converted to go on to explore wanting to own (and I very much believe horns are not right for some people at all) but I tend to think it’s also about how long you live with horns before they take you so completely to a point where you lose interest in owning or listening to any other kind of speaker… a bit like an abduction into speaker Stockholm syndrome.

There are those here now who have clearly had a great and very lengthy full time exposure to a range of horns and seem unlikely to ever go back to owning any other speaker type and I think that’s different to just having got some hours up in appreciating or even in being deeply impressed by some horns. I think it’s being totally committed and more likely to end up also then being further committed by your significant other if they catch you planning another one

 

[Kingrex]

Though it’s easy for some to be impressed by a good horn and converted to go on to explore wanting to own (and I very much believe horns are not right for some people at all) but I tend to think it’s also about how long you live with horns before they take you so completely to a point where you lose interest in owning or listening to any other kind of speaker… a bit like an abduction into speaker Stockholm syndrome.

There are those here now who have clearly had a great and very lengthy full time exposure to a range of horns and seem unlikely to ever go back to owning any other speaker type and I think that’s different to just having got some hours up in appreciating or even in being deeply impressed by some horns. I think it’s being totally committed and more likely to end up also then being further committed by your significant other if they catch you planning another one

I agree. I thought this the premis of Paul's statement.

In one of my YouTube videos, I railed against the sound of horns and how they are difficult for me to adjust to. They simply sound unnatural until my brain adjusts.

That we have powerful amps today only means we have more options. We should be thankful we have options.

 

[Robh3606]

But, that said, the idea of a horn’s superiority because of less strain and distortion presented to its connected power amplifier is a thing of the past when a big amplifier maybe cranked out 20 watts.

I think he is off base here. It's not the amp it's what speakers are doing. They put out an order of magnitude more distortion than amps in general. Depends on your listening habits and what SPL you listen at. As I see it speakers with sensitivities in the 80's on wrong side of the power curve. If you want "realistic" levels lets say 105 peaks you are dumping some serious power into them to get here.

In the upper 90's to 103 as a range you are running watts for the same levels and the speakers will never be thermally challenged at those power levels. You also are not pushing the amps hard so the whole audio chain is just loafing along. Sounds like a win to me.

I have a couple of systems and can easily move between cone and dome to Dynamic driver horn/waveguide hybrids with no issues Get enjoyment from both although they are different. I don't think modern 2 and 3rd generation bi-radials or waveguides sound like horns in the sense they don't have cupped hand syndrome, sound shouty ??? spelling?? of have any of the other attributes that gave horns a bad reputation.

Rob

 

[cjfrbw]

Love to see this forum without the Boomers.
It would probably go...<BOOM!>
Just leaving the headphone crowd and those who remember WE horns first time around.

That's funny. At the recent Burwell horn demo, there was a kid (is young audiophile more PC?) who showed up and played several cuts. I heard the younger Gordon talking with him. His only purpose for coming to the demo was to demonstrate to himself that a good speaker set up couldn't compete with his headphone rig, and he declared his headphone rig the winner.
Maybe there is an ignored neural programming phenomenon involved in which the listener is broken in as much as the equipment.

 

[cfgardei1]

Two DIAMETRICALLY-OPPOSED technologies are horn drivers and planar speakers; the first: extremely efficient and capable of extremely LOUD performance with very low power (but with poor imaging) and the second: low efficiency and CAN'T GET LOUD EVEN WITH A HOOVER-DAM-SIZED-AMP DRIVING THEM, but with amazing detail and soundstage! Yes: from the photo you can guess that I'm normally on the Magnepan forum - I just popped over here when I saw horns were being discussed...

You see, my dearly-departed dad had a Klipschorn (mono) in the early 60's (and kept until the mid-70's) and I grew up thinking the "boom and shriek" were how speakers sounded (don't hate me: the early K-horn - or at least his - was atrocious!) But, in the days of a "few watts/channel amplifiers", I blew away my jr. high school buddies playing my newly-discovered Foghat LP at 110dB!

Fast-forward to today: I love my 3.7i's (with 16 - 30Hz supplemented by a sub) and I have finally reached a point where I am truly happy with the way my system sounds. In other words: I have stopped shopping...

But (and this is the big "but"), even though I am near-60, I really like a lot of music (but, only occasionally) that most my age don't: System of a Down, Stabbing Westward, Korn, etc., etc. And, though I've listened to ALL of my these, and more, on the "Maggies" (and discovered instruments and mixing effects that I had NEVER heard before in dozens of previous listenings!), somehow 100dB peaks don't do them justice.

So, I have two listening rooms: one that has the Tidal MQAs streaming through the Maggies, and a 2nd one (in the basement, where I won't disturb any neighbors) that has - you guessed it: horns. I have a pair of LaScalas tucked into the corner.

Except for possibly the I.R.S. (which I never heard) I've never found a truly "good" AND a truly "loud" speaker. But, having both means that whatever I am in the mood for, there I go...