Getting rid of coloration in small boxes should be fairly straight forward, just use loads of bracing.
Bigger boxes are a bit harder without making the box too heavy to move around easily.
A disco I used to work for had 100 watt folded horn speakers and they sounded very wooden, a bit like when you hit wood with hammer or another piece of wood.
It sounded like the wood was vibrating.
I built a 600WRMS bass bin that was folded horn and that sounded wooden too. I binned it in the end and went back to a ported cabinet.
Bigger boxes are a bit harder without making the box too heavy to move around easily.
A disco I used to work for had 100 watt folded horn speakers and they sounded very wooden, a bit like when you hit wood with hammer or another piece of wood.
It sounded like the wood was vibrating.
I built a 600WRMS bass bin that was folded horn and that sounded wooden too. I binned it in the end and went back to a ported cabinet.
Interesting topic Angelo! Do you have any drawings/calculations of the round horn with TPL-150? Is it Tractrix based, LeCleach? I would be interested in building it, to test how it would sound. I also like the aestetichs better with this round horn, when the rest of the horns in the system are round.
Horn/Driver Protest
The high pass sections of your crossover network must have a slope greater than 12 db/oct and preferably 24 db/oct or more, depending on the capabilities of drivers and horns used. For reasons explained below, this is mandatory for successful use of compression driver horn assemblages.
Borrow or rent a DSP Crossover Unit for a week and explore the tradeoffs of HP and LP filter frequency and slope for your system.
“Horn Honk” and “Horn Coloration” are usually Bum-Raps for Acoustic Horn and Compression Driver technology. The causes for these maladies, more often than not, are due either to horn under sizing, or improper conditioning of the signal sent to the driver. There is a trade of bandwidth for efficiency going on here that needs to be recognized in the crossover design.
To maintain a constant sound pressure level, a driver’s volume displacement must increase as frequency declines at a rate proportional to the reciprocal of frequency squared or 12 dB per octave. With a shallow filter slope (<= 12 dB/Oct), it is clear that diaphragm excursion will either remain constant or continue to increase with a frequency decline in the driving signal. If the driver diaphragm fails to move in this fashion, the energy of the driving signal will be dissipated in the voice coil as heat. Recognition of these conditions is particularly important to the rational operation or compression driver/horn assemblages. Here as frequency declines towards horn cut-off frequency,
increasing diaphragm displacement becomes limited by the close proximity of a phase plug;
the acoustic load seen by the diaphragm rapidly disappears,
while back waves propagate from the horn mouth and impinge on the diaphragm with increasing intensity.
Is it any wonder that the sound coming from horned drivers operated under these conditions, will at the very least, be “colored”, if not, down-right “nasty”.
Regards,
WHG
The high pass sections of your crossover network must have a slope greater than 12 db/oct and preferably 24 db/oct or more, depending on the capabilities of drivers and horns used. For reasons explained below, this is mandatory for successful use of compression driver horn assemblages.
Borrow or rent a DSP Crossover Unit for a week and explore the tradeoffs of HP and LP filter frequency and slope for your system.
“Horn Honk” and “Horn Coloration” are usually Bum-Raps for Acoustic Horn and Compression Driver technology. The causes for these maladies, more often than not, are due either to horn under sizing, or improper conditioning of the signal sent to the driver. There is a trade of bandwidth for efficiency going on here that needs to be recognized in the crossover design.
To maintain a constant sound pressure level, a driver’s volume displacement must increase as frequency declines at a rate proportional to the reciprocal of frequency squared or 12 dB per octave. With a shallow filter slope (<= 12 dB/Oct), it is clear that diaphragm excursion will either remain constant or continue to increase with a frequency decline in the driving signal. If the driver diaphragm fails to move in this fashion, the energy of the driving signal will be dissipated in the voice coil as heat. Recognition of these conditions is particularly important to the rational operation or compression driver/horn assemblages. Here as frequency declines towards horn cut-off frequency,
increasing diaphragm displacement becomes limited by the close proximity of a phase plug;
the acoustic load seen by the diaphragm rapidly disappears,
while back waves propagate from the horn mouth and impinge on the diaphragm with increasing intensity.
Is it any wonder that the sound coming from horned drivers operated under these conditions, will at the very least, be “colored”, if not, down-right “nasty”.
Regards,
WHG
Exactly what WHG said. The crossover should be at least one octave above the horn cutoff. And you must limit excursion for the lowest frequencies, which means at least a 12db/octave crossover.
I've found the combo of JBL2445 (2" exit) CD with John's paper mache horns to have zero to very little coloration. Paper is a good material to make a horn out of. It has inherent damping ability and it sounds very natural. Of course, not everyone is as good a fabricator as John.
inlowsound.com
I've found the combo of JBL2445 (2" exit) CD with John's paper mache horns to have zero to very little coloration. Paper is a good material to make a horn out of. It has inherent damping ability and it sounds very natural. Of course, not everyone is as good a fabricator as John.
inlowsound.com
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Bah - all of mine come out looking like a school science project.
I agree that one driver needs to be used for the 300 to 3000 Hz range - and nooooooo crossovers there either!!!
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Bah - all of mine come out looking like a school science project.
I agree that one driver needs to be used for the 300 to 3000 Hz range - and nooooooo crossovers there either!!!
Thomas,
The essential design elements of your school project Volcano and a midrange horn are completely different, IOW: you're not going to realize a 2-fer.
I certainly agree on the frequency range.
Best Regards,
Terry
Hi Angeloitacare,
You asked whether I have done comparisons of my DIY speakers with the Altec 32 horn to direct radiators. Definitely! Here is a short list of my primary speakers over the past couple decades: FMI 80 with RTR ESR-6 electrostat tweeters, Fried H, Rogers LS3/5a, Strathearn ribbons, Martin Logan CLS (all models through the II-Z), Thiel 3.6 and Spendor SP-100. Plus lots of DIY efforts scattered throughout. What is missing from that list are horn speakers, for the simple reason that I have always reacted negatively to horn loaded speakers. Among the horns that I have heard over the years, mostly at dealers but also at shows, that I have considered too colored for my tastes: Altec A7 VOT, JBL Paragon, all sorts of JBLs, EVs, Klipschs, etc. back in the 60s and 70s, and more recently Avant Garde Duos, Classic Audio Reproductions and GoTo horns. This summer I heard a new speaker, the Volti Vittora, which is fully horn loaded, and it actually sounded pretty good. I wasn't able to listen long enough to decide whether it was neutral enough for me to live with longterm, but at least it didn't have obvious colorations that bothered me. My point in going through this history is to provide some context. I have certainly heard my share of speakers over the years, and I have consistently taken an almost immediate dislike to horn speakers. My present DIY speakers using the Altec 32 horn are the exception. To my ears, they do not have any horn colorations.
You asked whether I have done comparisons of my DIY speakers with the Altec 32 horn to direct radiators. Definitely! Here is a short list of my primary speakers over the past couple decades: FMI 80 with RTR ESR-6 electrostat tweeters, Fried H, Rogers LS3/5a, Strathearn ribbons, Martin Logan CLS (all models through the II-Z), Thiel 3.6 and Spendor SP-100. Plus lots of DIY efforts scattered throughout. What is missing from that list are horn speakers, for the simple reason that I have always reacted negatively to horn loaded speakers. Among the horns that I have heard over the years, mostly at dealers but also at shows, that I have considered too colored for my tastes: Altec A7 VOT, JBL Paragon, all sorts of JBLs, EVs, Klipschs, etc. back in the 60s and 70s, and more recently Avant Garde Duos, Classic Audio Reproductions and GoTo horns. This summer I heard a new speaker, the Volti Vittora, which is fully horn loaded, and it actually sounded pretty good. I wasn't able to listen long enough to decide whether it was neutral enough for me to live with longterm, but at least it didn't have obvious colorations that bothered me. My point in going through this history is to provide some context. I have certainly heard my share of speakers over the years, and I have consistently taken an almost immediate dislike to horn speakers. My present DIY speakers using the Altec 32 horn are the exception. To my ears, they do not have any horn colorations.
Angelo
Have you really not read any of my work? I address each of these points in turn and show why they exist and how to alleviate them. Ask anyone who has heard one of my waveguides and they will tell you that they are the most uncolored "horns" that they have ever heard. You've just been looking in the wrong places, thats all.
And No! smaller is not better, bigger is. When done right of course!
Thomas,
The essential design elements of your school project Volcano and a midrange horn are completely different, IOW: you're not going to realize a 2-fer.
I certainly agree on the frequency range.
Best Regards,
Terry
Yeah - the trick is that I still haven't been able to really find a dynamic and highly efficient mid range driver that will keep up with my AMT1's - sigh. I'm just having some fun about the horns. Despite attempts with the horns for domestic listening it's still the AMT's for me. For clubs and outdoors tho - ya just gotta go with the horns!!! But then I don't listen to PA's outdoors because the horns drive me nuts - and I'm to cheap to pay the cover charge to get into the clubs!!!! Well - that and the fact that the bands don't really get cooking until well past my bed time.
I have JBL Array 1400 clones and a JBL 880 Array center. They use the latest generation JBL Biradials and they have no audible horn colloration what so ever. I also use JBL PT waveguides and can say the same thing about them. At least the one I use.
So yes there is a remedy try the more modern horn profiles.
Rob
So yes there is a remedy try the more modern horn profiles.
Rob
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hi Earl
unfortunately, i have never heard oblate spheroid waveguides with foam inside . Peter (PK) has however tried the B & C DE250 compression driver, which seems the compression driver of your choice, and he favours the Beyma's.
I have JBL Array 1400 clones and a JBL 880 Array center. They use the latest generation JBL Biradials and they have no audible horn colloration what so ever. I also use JBL PT waveguides and can say the same thing about them. At least theone I use..
So yes there is a remedy try the more modern horn profiles.
Rob
I have my big horn system for 3 years now, and neither i, nor anyobody of all visitors i had during this time, that heard the system, ever reclaimed of hearing horn coloration. But after making direct A/B listening comparisons with the Beyma's, i thought to myself : how is it possible, that i did not observe these colorations in the midrange before ?? The conclusion i draw from this is:
the ear can be cheat very easily. Specially , if there is no reference point.
I don't believe in people, which say : " i have a trained ear " . For me, what is revealing, is direct comparison with direct radiators......
Its indeed quit remarkable, how unorthodox and unexpected solutions and speaker designs can sound marvellous. So i don't wonder, if even JBL's, or Altec's can sound well, giving the right tuning, and circumstances.....
Well then you are far behind the times. The quest you seek has been answered, you need only seek it out. My 45+ years of study on this problem must surely have led to something. That or I am a complete idiot (don't answer that question!)
Beyma's, JBL's, B&C, its not the driver that makes a difference, its the waveguide. We proved that almost a decade ago.
I'll bet you are a bit biased, but I can understand that.
So, tell me, have you had a chance to listen to some of the ribbon tweeters such as the Beyma TPL-150 or the RAALs and how do they compare to the oblate spheroid horns?
That is kind of a subjective question, but my interest is how some of these high end ribbons perform compared to high end horns in the realm of HiFi.
OK , explain those colorations (or lack of them in ribbon)? Direct radiators color differently and most of them terribly , they just more often of pleasant type
Well, tell me what are the components that make up coloration. In other words, what is the definition of coloration.
I would think a starting point would be THD, IMD, and how these are perceived by the ear as one attribute. What would be others?
i used the otangelix ellipsoid formula. here it goes :
ax2 + bx + c (2 – i)(3 + 4i) = (2)(3) + (2)(4i) + (–i)(3) + (–i)(4i)= (2)(4i) + (–i)(3) + (–i)(4i)= 00
just kidding
!! - calculations and formulas are not my cup of tea.....i've drawn the waveguide of the TPL-150 H , and used its opening angle as base to design the curve of my own wave guide. I will use flexible multiplex , four layers of 4mm, total 16mm wall thickness, glued together, to make the waveguides.
Me too. Square and round does not mix well, i don't like the aesthetics - see Le Grand Castine......
hi Earl
for as little as i understood, you consider foam a key feature to avoid HOM's, and subsequently colorations as well. A few years back, i was actually interested to try out your solution. I made even a search of foam, but i did not find a supplier, neither in the u.s. nor in brazil, despite i contacted a few companies. When they see that the quantity is very small, they do not want to spend time, its just not worth to them. I asked you as well, buy you had no availability either. Beside this, foam is rather a controversial solution, with opinions that diverge a lot.....
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