Given a single imaginary transducer with identical performance as that of David's woofer+horn combo, would we still prefer the woofer+horn combo with the crossover? David's stand, IMO, is that there would be no difference in the sound of the two speakers.
Not exactly my stand.
Such a large part of loudpseaker design is shaping the sound character, by shaping the frequency response using whatever means are available.
With decent drivers in a multiway system you have a broad latitude in response shaping with the crossover network.
With a fullrange horn you can either redesign the compression driver or play with the horn shape. That would be flare rate, flare type, mouth dimensions and the overall curling. Most changes would mean draw, cut and put together a new horn.
I would have a much easier time playing with network variables than, say, building another coiled horn prototype. That doesn't guarantee the end result is better, just that the itterations are much easier.
Thats all I was saying.
David
Such a large part of loudpseaker design is shaping the sound character, by shaping the frequency response using whatever means are available.
With decent drivers in a multiway system you have a broad latitude in response shaping with the crossover network.
With a fullrange horn you can either redesign the compression driver or play with the horn shape. That would be flare rate, flare type, mouth dimensions and the overall curling. Most changes would mean draw, cut and put together a new horn.
I would have a much easier time playing with network variables than, say, building another coiled horn prototype. That doesn't guarantee the end result is better, just that the itterations are much easier.
Thats all I was saying.
David
Anybody heard both the W.E. and Tom Danley's stuff?
I have a theory (entirely unsubstantiated) that I'd love to see tested. That being, that it isn't the crossover in the vocal range that some people find so obtrusive, but more specifically a crossover in the vocal range that hands over to a non-coincident driver and/or one which doesn't track phase for reasons of physical position or other causes. Most coaxial or coincident systems fail to have the "magic" because their horn/waveguide components are crippled (being of course woofer cones first and foremost) and may lack what I understand to be some thoughtful crossover work that keeps the drivers in Danley systems tracking in phase over much of their ranges, even passing recognizable square waves (for whatever that may be worth).
So, anybody heard both? (I've not heard either.) Or have any thoughts as to the merit of these suppositions?
I have a theory (entirely unsubstantiated) that I'd love to see tested. That being, that it isn't the crossover in the vocal range that some people find so obtrusive, but more specifically a crossover in the vocal range that hands over to a non-coincident driver and/or one which doesn't track phase for reasons of physical position or other causes. Most coaxial or coincident systems fail to have the "magic" because their horn/waveguide components are crippled (being of course woofer cones first and foremost) and may lack what I understand to be some thoughtful crossover work that keeps the drivers in Danley systems tracking in phase over much of their ranges, even passing recognizable square waves (for whatever that may be worth).
So, anybody heard both? (I've not heard either.) Or have any thoughts as to the merit of these suppositions?
Couldn't passive (or active) filters be applied to a full range horn as well? I don't see why the same toolbox wouldn't be available?
My view, not that anyone can take it to the bank, is that the harmonic series that comes off two different drivers, one a low frequency driver and the other a high frequency driver can never properly combine as far as the ear is concerned. Put another way, they will combine, but the combination is somewhat different than a single source that covers the same range.
Now the discussion can shift to the question of just how good, and how little differential can be obtained with the midband split vs. the wide range compression driver/horn and then of course compare all the other trade-offs.
It's just not a simple relationship that can be considered with just a single or even multiple parameters or factors...
_-_-bear
Now the discussion can shift to the question of just how good, and how little differential can be obtained with the midband split vs. the wide range compression driver/horn and then of course compare all the other trade-offs.
It's just not a simple relationship that can be considered with just a single or even multiple parameters or factors...
_-_-bear
This is what I do on the compression horns in my car to flatten out their response, there is no reason you couldn't do this with a full range horn. For those of you who don't know about HLCD's in cars here is a great place to learn more. HLCD - DIYMA Car Audio Forum
Hi bear
You really can make a multi-way horn that sounds and measures like one driver.
Take an SH-50, that, you can walk up to it and then with the grill off stick your head deep inside the mouth and at no point have any idea there is more than one source somewhere in front of you.
If you look at the polar plots for it, you see high directivity and one source. If you look at the impulse response it is one driver. That is not done for marketing reasons but because of how it works and sounds in use in an area where it is very hard to make good sound.
Your right, it isn’t simple or easy but it is possible if you treat a horn according to what a given part is doing at a given frequency.
The acoustic impedance transformation a horn depends on for efficiency has a “high pass” component and that based on the rate of expansion.
For example, a 30 hz bass horn has to expand no faster than doubling it’s area every 24 inches while at 300Hz it’s every 2.4 inches.
A conical horn like I use while having near constant directivity, has inferior low frequency loading and will only work well as a high frequency horn. The horns we make now were born when I realized the “why” in a comment Don Davis made about that loading at a Synaudcon in the late 80’s.
The light went on about 15 years later, it was that expansion rate criteria that was causing the poor loading, at the apex the expansion rate is very rapid, a high frequency horn.
Further down the horn, the expansion was slower and more like a mid horn and a quick estimate and a trip to the garage and the first unity horn was born. A cool thing is that the side mounted drivers connect through the horn though an acoustic low pass filter.
This is the trapped air under the cones and the port mass which are sized so that the low pass corner is somewhat above the low pass electrical crossover. This reduces the inevitable harmonic distortion drivers produce above their operating band when low passed.
You could now use one large CD horn so you have pattern control over a wide band and drive it in sections where it was acoustically suited for the frequency involved, you treat sound according to it’s size.
All the drivers add and combine less than ¼ wl apart in the horn, the result is one source.
Passive crossover normally introduce phase shift, an effect that makes the hf source to speak first and the lf drivers last.
By having the hf driver farthest to the rear and the woofers most forward, some of all of that phase shift can be eliminated using an adapted crossover shape (not ones with names but shapes that do the job).
As the passive xover also deals with the drivers electrical impedance's while shaping the responses, this is the most time consuming part now days.
The design “rules” gradually evolved to the current Synergy horns we make and sell for commercial sound.
One of the fellows here pointed out an interesting thing.
To the degree an impulse response accurately characterizes a loudspeaker, there is a way to hear what the WE, mine and other speaker sound like. It won’t tell squat about stereo imaging but it does seem to capture “what it sounds like”.
Down load the “gratisvolver” at Catt acoustics here;
CATT Download Area
Load an impulse response wavefile from arta or other program.
Find a music track on your computer and select it and convolve them.
The result is what the music sounds like with that impulse response.
When I tried it with a 2sec wave impulse from an SH-50 in my room and listened with good headphones, it did sound a lot like that speaker in my room.
Anyway, it would not be hard to record the impulse response from many different kinds of speakers and audition them.
7 years ago, we spent a lot of time making generation loss recordings.
I guess that was partly a reality check thinking that for a signal accurate speaker, the greater the number of generations that you could go the better. This convolution approach would have been a cool fast way to arrive at multiple generations of sonic flaws via dsp magic.
Best,
Tom Danley
You really can make a multi-way horn that sounds and measures like one driver.
Take an SH-50, that, you can walk up to it and then with the grill off stick your head deep inside the mouth and at no point have any idea there is more than one source somewhere in front of you.
If you look at the polar plots for it, you see high directivity and one source. If you look at the impulse response it is one driver. That is not done for marketing reasons but because of how it works and sounds in use in an area where it is very hard to make good sound.
Your right, it isn’t simple or easy but it is possible if you treat a horn according to what a given part is doing at a given frequency.
The acoustic impedance transformation a horn depends on for efficiency has a “high pass” component and that based on the rate of expansion.
For example, a 30 hz bass horn has to expand no faster than doubling it’s area every 24 inches while at 300Hz it’s every 2.4 inches.
A conical horn like I use while having near constant directivity, has inferior low frequency loading and will only work well as a high frequency horn. The horns we make now were born when I realized the “why” in a comment Don Davis made about that loading at a Synaudcon in the late 80’s.
The light went on about 15 years later, it was that expansion rate criteria that was causing the poor loading, at the apex the expansion rate is very rapid, a high frequency horn.
Further down the horn, the expansion was slower and more like a mid horn and a quick estimate and a trip to the garage and the first unity horn was born. A cool thing is that the side mounted drivers connect through the horn though an acoustic low pass filter.
This is the trapped air under the cones and the port mass which are sized so that the low pass corner is somewhat above the low pass electrical crossover. This reduces the inevitable harmonic distortion drivers produce above their operating band when low passed.
You could now use one large CD horn so you have pattern control over a wide band and drive it in sections where it was acoustically suited for the frequency involved, you treat sound according to it’s size.
All the drivers add and combine less than ¼ wl apart in the horn, the result is one source.
Passive crossover normally introduce phase shift, an effect that makes the hf source to speak first and the lf drivers last.
By having the hf driver farthest to the rear and the woofers most forward, some of all of that phase shift can be eliminated using an adapted crossover shape (not ones with names but shapes that do the job).
As the passive xover also deals with the drivers electrical impedance's while shaping the responses, this is the most time consuming part now days.
The design “rules” gradually evolved to the current Synergy horns we make and sell for commercial sound.
One of the fellows here pointed out an interesting thing.
To the degree an impulse response accurately characterizes a loudspeaker, there is a way to hear what the WE, mine and other speaker sound like. It won’t tell squat about stereo imaging but it does seem to capture “what it sounds like”.
Down load the “gratisvolver” at Catt acoustics here;
CATT Download Area
Load an impulse response wavefile from arta or other program.
Find a music track on your computer and select it and convolve them.
The result is what the music sounds like with that impulse response.
When I tried it with a 2sec wave impulse from an SH-50 in my room and listened with good headphones, it did sound a lot like that speaker in my room.
Anyway, it would not be hard to record the impulse response from many different kinds of speakers and audition them.
7 years ago, we spent a lot of time making generation loss recordings.
I guess that was partly a reality check thinking that for a signal accurate speaker, the greater the number of generations that you could go the better. This convolution approach would have been a cool fast way to arrive at multiple generations of sonic flaws via dsp magic.
Best,
Tom Danley
Well, before we can answer that, we would have to figure out what exactly a WE555 does--what are its parameters? I'd love to see some data, which seems very hard to come by...
I'd guess that several of them would be able to reach at least as low. Some of them have surprisingly low Fs and more swept volume than I'm guessing a 555 has. I suppose they might be more challenged to reach as high, as none of them have aluminum diaphragms. Internally, several of them are virtual clones of the 555, with rear magnets and single-slit phase plugs. Only the Selenium has a ferrite magnet. The rest have either AlNiCo or NdFeB magnets.
What has the biggest impact on bandwidth limits is the giant 15A horn itself--its airload dominates the diaphragm.
Next month I will be in that rather exclusive club and may be able to comment.
FWIW, I've heard the 15A with a 555 and also with a Westrex 1950's vintage driver. A lot of the magic is in the horn, IMO, not just the driver.
Your point is correct if you see it from the engineering cost (time is money). Next is to use digital x-overs with the ability to have more flexibility - the Beringer fraction. But if this is the heaven .... why reinvent the wheel again?
In the times when the WE stuff was developed - and others as well - they had to use other engineering practices coming to solutions.
The issue with fullrange is to fit most of the frequenxy range without need of an X-over, so does the WE555 as well. What horn you use in front is another point and sight of view - for example use a WE22A-horn instead of the 15A-horn and increase the x-over frequency. So many advantages and so many solution, a playground for each of us.
I think a straight horn of equal size would sound better.
I think the sound as to do with the bandwidth.
Hi Pano
Hey how close are you to here?;
Candler, NC 28715
If close, maybe i can do something before then.
Best,
Tom
Fwiw, you folks might want to look at a B&C DCM-50 as something similar in bw.
Hey how close are you to here?;
Candler, NC 28715
If close, maybe i can do something before then.
Best,
Tom
Fwiw, you folks might want to look at a B&C DCM-50 as something similar in bw.
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Tom,
Ur design is very cool. I have to read a bit more about it, time is not on my side right now... the software seems like a very intriguing thing. I wonder how it corresponds to the way a given speaker sounds - problem is that you end up with two speakers worth of alteration, the one you normally listen to and then the one that the impulse response wants it to be, this of course is ignoring any possible contribution that the software or digital playback via the computer may or may not add. Intriguing though. The marvels of the digital age, eh?
I did send you a PM some time ago regarding a question that relates to the Unity and Synergy designs, one of my main concerns beyond the basic operating principle.
My mind is thick - when people talk about the expansion, I think of the shape or slope of the horn profile, not the area of expansion at a given distance from the throat. Need to correct that...
Bill F, there are freq response curves from WE, but in old journal articles. I have them, somewhere, in a binder, somewhere... otherwise I would scan and post. The copyright must have expired on those... 😀 WE and Bell Labs are defunct anyhow... and yes they were measured down to 75Hz in the plane wave tube set up... don't think that is a usable F3 point though.
Got pix of those drivers you say are similar or identical to the WE? I think I looked at them and decided that they were not really particularly the same some years back. Perhaps it is a time for another look...
_-_-bear
Ur design is very cool. I have to read a bit more about it, time is not on my side right now... the software seems like a very intriguing thing. I wonder how it corresponds to the way a given speaker sounds - problem is that you end up with two speakers worth of alteration, the one you normally listen to and then the one that the impulse response wants it to be, this of course is ignoring any possible contribution that the software or digital playback via the computer may or may not add. Intriguing though. The marvels of the digital age, eh?
I did send you a PM some time ago regarding a question that relates to the Unity and Synergy designs, one of my main concerns beyond the basic operating principle.
My mind is thick - when people talk about the expansion, I think of the shape or slope of the horn profile, not the area of expansion at a given distance from the throat. Need to correct that...
Bill F, there are freq response curves from WE, but in old journal articles. I have them, somewhere, in a binder, somewhere... otherwise I would scan and post. The copyright must have expired on those... 😀 WE and Bell Labs are defunct anyhow... and yes they were measured down to 75Hz in the plane wave tube set up... don't think that is a usable F3 point though.
Got pix of those drivers you say are similar or identical to the WE? I think I looked at them and decided that they were not really particularly the same some years back. Perhaps it is a time for another look...
_-_-bear
Please consider, during the late 1920's there was a rush to put sound into the theaters at any cost.
In todays theaters cost is a major factor, but not really then.
Yes we can do better today, but at what cost?
Yes there is better technology, but at what cost?
Makes me think of people (not audio enthusiasts) who say the radios from the fifties are better than those today. They don't see that for the first one had to pay two month-wages and the latter are bought for the price of ten pound beefsteak in the food discounter.