I've been thinking about this for a while. Anyone ever do this? Could be used for personal home listening, parties, outdoors, DJing, small live gigs, etc.. a tough thing to pull off, but I'm wondering what the result would be like. I'm thinking one might end up with something that sounds very similar to the typical sound of a movie cinema, but perhaps sounding a lot bigger and better in the typical listening room, plus extra low-end from room gain and a better woofer/enclosure combo.
Also, I'm aware of the problems associated with a 2" exit compression driver running above 10 KHz, but I'm curious as to just how audible it'd really be. More than anything, I think the high directivity above 10 KHz and the resulting off-axis downward slope above 8-10 KHz as a result would be more problematic than anything. But I still wonder what it'd be like.
So, a single 18" serious pro sound woofer in a large vented enclosure with a 2" exit driver mated to a large pro sound horn, digitally crossed at 400-500 Hz, 8th order lowpass on the woofer and 4th order highpass on the compression driver.
For example, here are some of the specific components I've been eyeing:
Goldwood GM-450PB 2" High Frequency Horn
Peavey 18" Low Rider Subwoofer Speaker Driver
Peavey 18" Low Max Subwoofer Speaker Driver
Choice of compression driver is still very much up in the air.
Anyway, either of the above woofers would work well in 10^3 tuned to about 30 Hz, capable of 120-123 dB continuous @ 1m before Xmax starts coming into play. I'm curious though about the frequency response of these woofers, since Peavey never seems to list measurements. They state 500 Hz and 1 KHz, but I somehow doubt they're so limited. Inductance for both woofers is fairly low too, compared to other woofers in their class.
I've used these links below as a general idea of what to expect from such a 90 degree 2" exit horn and driver combo. These horns seem very similar to that cheap Goldwood I listed above:
http://prodance.cz/protokoly/RCF_H9040_DE750.pdf
http://prodance.cz/protokoly/fh2450_de750.pdf
Speaking of the Goldwood horn, P.Audio makes an identical one for a lot more money. I'd typically stay away and flat out ignore anything from Goldwood, but this 2" horn might turn out to be a really good value.
Anyway, just contemplating, and thought I'd inquire for any thoughts and experiences regarding such a project.
edit:
Also, my biggest issue with the above is the digital crossover, in regards to volume control. Is there still not a readily available volume control with XLR outputs for DCX2496 and the likes? Why the hell not??
Also, I'm aware of the problems associated with a 2" exit compression driver running above 10 KHz, but I'm curious as to just how audible it'd really be. More than anything, I think the high directivity above 10 KHz and the resulting off-axis downward slope above 8-10 KHz as a result would be more problematic than anything. But I still wonder what it'd be like.
So, a single 18" serious pro sound woofer in a large vented enclosure with a 2" exit driver mated to a large pro sound horn, digitally crossed at 400-500 Hz, 8th order lowpass on the woofer and 4th order highpass on the compression driver.
For example, here are some of the specific components I've been eyeing:
Goldwood GM-450PB 2" High Frequency Horn
Peavey 18" Low Rider Subwoofer Speaker Driver
Peavey 18" Low Max Subwoofer Speaker Driver
Choice of compression driver is still very much up in the air.
Anyway, either of the above woofers would work well in 10^3 tuned to about 30 Hz, capable of 120-123 dB continuous @ 1m before Xmax starts coming into play. I'm curious though about the frequency response of these woofers, since Peavey never seems to list measurements. They state 500 Hz and 1 KHz, but I somehow doubt they're so limited. Inductance for both woofers is fairly low too, compared to other woofers in their class.
I've used these links below as a general idea of what to expect from such a 90 degree 2" exit horn and driver combo. These horns seem very similar to that cheap Goldwood I listed above:
http://prodance.cz/protokoly/RCF_H9040_DE750.pdf
http://prodance.cz/protokoly/fh2450_de750.pdf
Speaking of the Goldwood horn, P.Audio makes an identical one for a lot more money. I'd typically stay away and flat out ignore anything from Goldwood, but this 2" horn might turn out to be a really good value.
Anyway, just contemplating, and thought I'd inquire for any thoughts and experiences regarding such a project.
edit:
Also, my biggest issue with the above is the digital crossover, in regards to volume control. Is there still not a readily available volume control with XLR outputs for DCX2496 and the likes? Why the hell not??
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pinkmouse:
Thanks for the input. I wonder what specifically caused the bad sound from the 18's you've experienced? I guess I was just thinking the slightly higher directivity from 500Hz-1KHz might be beneficial, plus the simplicity, no subwoofers necessary (-3dB @ 30Hz), extra wow factor, etc.
el`Ol:
Is this what you're talking about? Eggo1
Interesting indeed. Where to get a massive waveguide like that? Cost? I'm aware of the Le Cléac’h Azurahorns, if that's what it is.
Anyway, for some reason, I just find the thought of hosting tunes for a crowd or providing the sound for a small live concert, then rolling it inside the same night to relax and listen to some tunes or watch a flick.. appealing. I already have most of the equipment to do it, would just need a few more odds and ends, cabling, and of course.. the speakers.
Thanks for the input. I wonder what specifically caused the bad sound from the 18's you've experienced? I guess I was just thinking the slightly higher directivity from 500Hz-1KHz might be beneficial, plus the simplicity, no subwoofers necessary (-3dB @ 30Hz), extra wow factor, etc.
el`Ol:
Is this what you're talking about? Eggo1
Interesting indeed. Where to get a massive waveguide like that? Cost? I'm aware of the Le Cléac’h Azurahorns, if that's what it is.
Anyway, for some reason, I just find the thought of hosting tunes for a crowd or providing the sound for a small live concert, then rolling it inside the same night to relax and listen to some tunes or watch a flick.. appealing. I already have most of the equipment to do it, would just need a few more odds and ends, cabling, and of course.. the speakers.
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The woofers you cited do not play very deep for HiFi use.
The system you propose might lend well for sound reinforcement activities, but I would be surprised if you could cobble together a 2-Way with an 18" woofer and get effective results for good HiFi listening.
I am experimenting with a 15" Acoustic Elegance TD-15H and a Beyma TPL-150 for a two way. Cabinets are about 50% completed and I might get them done today.
However, I think I am pushing the limit with the 15" and worried that the result will be less than hoped. I would not expect very good results with an 18" due to the larger cone surface and directivity issues at such a high crossover point for an 18.
The system you propose might lend well for sound reinforcement activities, but I would be surprised if you could cobble together a 2-Way with an 18" woofer and get effective results for good HiFi listening.
I am experimenting with a 15" Acoustic Elegance TD-15H and a Beyma TPL-150 for a two way. Cabinets are about 50% completed and I might get them done today.
However, I think I am pushing the limit with the 15" and worried that the result will be less than hoped. I would not expect very good results with an 18" due to the larger cone surface and directivity issues at such a high crossover point for an 18.
I wouldn't cross that goldwood horn below 1khz (due to the mouth size). And wrap the mouth in foam, it will sound better.
It's hard to find an 18" that goes that high to catch the horn crossed at 1khz also. Like pinkmouse said, it's a job easier for a 15" (but harder to find one looking at freq. graphs nowadays).
A decade is a common range for horns (500-5khz), but people break that rule often, especially that 2-way with 18" or even the 8" full range drivers front horn loaded crossed at 200hz. Dispersion gets to be a big preblem with non cd-horns as you go up in frequency.
And getting a 2" up past 8khz, you can be asking for trouble. Most diaphrams are in pure breakup mode up there, they masage cone resonances and play with phase plugs to get a reasonable / flatish response.
And you still may want a subwoofer (for the .1 low freq effects from dolby digital / dts). Movies just arn't the same. I know I miss the lfe at times, but may fix that in the future. But I like the bass slam from a big 2-way and bass integration compared to 3-ways.
Norman
An externally hosted image should be here but it was not working when we last tested it.
It's hard to find an 18" that goes that high to catch the horn crossed at 1khz also. Like pinkmouse said, it's a job easier for a 15" (but harder to find one looking at freq. graphs nowadays).
A decade is a common range for horns (500-5khz), but people break that rule often, especially that 2-way with 18" or even the 8" full range drivers front horn loaded crossed at 200hz. Dispersion gets to be a big preblem with non cd-horns as you go up in frequency.
And getting a 2" up past 8khz, you can be asking for trouble. Most diaphrams are in pure breakup mode up there, they masage cone resonances and play with phase plugs to get a reasonable / flatish response.
And you still may want a subwoofer (for the .1 low freq effects from dolby digital / dts). Movies just arn't the same. I know I miss the lfe at times, but may fix that in the future. But I like the bass slam from a big 2-way and bass integration compared to 3-ways.
Norman
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nope, I'd never tolerate a large setup, except mine, lol.
You can watch / listen to Tron Legacy movie / soundtrack at "11".
Norman
Or Judge Judy yelling "I'm Speaking!" @ 120db.
Been looking at doing something similar - I've narrowed in on these two 18's from Beyma that will get you in the 1k/2k ballpark. I've not heard them however so no idea how well they would sound. BIG box I'm guessing and not exactly cheap. usspeakers has prices online for these as well....
http://profesional.beyma.com/pdf/18P80NdE.pdf
http://profesional.beyma.com/pdf/18G40E.pdf
http://profesional.beyma.com/pdf/18P80NdE.pdf
http://profesional.beyma.com/pdf/18G40E.pdf
Rising distortion, plus the directivity. Directivity can be useful, but for a single box PA system, where people may well be listening from all over the place, you get holes in the response. Not good. I tend to use Norman's rule of thumb, maximum of a decade for each driver, so in your case that would be 20-200Hz, Stick the mid in to do 200-2K, then a nice 1" CD and you're sorted.
yup, listening to wildly varrying dispersion speakers can be unnerving while walking around a room.
I'm so tempted to try the stereolab 400hz round tractrix (crossing 24db LR @ 600hz), but someone here had them and loved them, till he stood up. The dispersion was maybe 1' wide at 10' at / above 5khz. But that horn would make a great 3 way (like avante garde) crossing to a tweet.
Rule of thumb (not mine) based on dispersion cross a 12" at 1.2khz, 15" at 800hz, and I'd have to estimate an 18" at 500hz.
And you don't have to use the perfect ported box. My drivers want 8ft3 to tune to around 40hz. I put both of them in 8ft3 and tune to 30hz. Works great.
I'm so tempted to try the stereolab 400hz round tractrix (crossing 24db LR @ 600hz), but someone here had them and loved them, till he stood up. The dispersion was maybe 1' wide at 10' at / above 5khz. But that horn would make a great 3 way (like avante garde) crossing to a tweet.
Rule of thumb (not mine) based on dispersion cross a 12" at 1.2khz, 15" at 800hz, and I'd have to estimate an 18" at 500hz.
And you don't have to use the perfect ported box. My drivers want 8ft3 to tune to around 40hz. I put both of them in 8ft3 and tune to 30hz. Works great.
Seems to me that where one crosses depends greatly upon the directivity, as well as the natural roll off of the drivers used (inherent high-pass slope and frequency of the horn/driver combo, and inherent steep cut off frequency of the woofer). It appears that one must choose a crossover frequency and slopes that end up matching the phase and delay of both drivers with all their inherent limitations, while maintaining a smooth transition of directivity at the same time.
Obviously, depending on the size of the woofer and horn, there will be a relatively sudden narrowing of directivity. Done correctly, this transition should be smooth. For a 2-way 15" or 12" system done correctly, the transition from a rather omni-directional polar pattern to a more directional point source will take place around 1 KHz or so. By using an 18" woofer and 8th order slopes, one could push this down a bit further, perhaps an ocatave lower. Theoretically, one could even cross a 21" woofer to a large format 2" horn at it's cut-off frequency and still easily avoid excessive beaming, although steep 8th order acoustic slopes would likely be necessary, as with the 18" system, due to the inherent 4th order high-pass of the horn, and natural cutoff of the 21" woofer might require some tricks while attempting to match phase, just like any other loudspeaker system, although I've seen many 21" woofers with relatively smooth on-axis response up to 2 KHz.
With 15's and 12's mated to 2" exit drivers, one can cross an octave or so higher while using shallower slopes and differing xo frequencies to attempt to match them while ending up with a smooth response, but this is all very driver dependent and seems very tricky, at least for me.
Personally, I've never liked steep crossover slopes, but with horns and high SPL, it's pretty much mandatory. No 2nd order acoustic slopes here. So, with all of this said, I was just debating the sacrifice of having to use 8th order acoustic slopes with all their nasty ringing (which becomes even more apparent at high volume levels IME). However, it seems as though this approach of using the horn's high-pass would be a much easier task than attempting to cross an octave or more above it. Simply add a 4th order high-pass to the horn's existing 4th order high-pass to end up with an 8th order acoustic slope, and 8th order low-pass on the woofer (or 7th might work, due to the woofer's inherent roll off). This seems much easier to me than crossing well above the horn's cut off frequency and trying to match phase response and everything of both drivers. At this point, though, I question crossing at the horn's cut-off frequency. What negative effects would this cause? For example..
..Why? I'm curious about things like this. What specific role does the size of the mouth of a horn play?
Obviously, depending on the size of the woofer and horn, there will be a relatively sudden narrowing of directivity. Done correctly, this transition should be smooth. For a 2-way 15" or 12" system done correctly, the transition from a rather omni-directional polar pattern to a more directional point source will take place around 1 KHz or so. By using an 18" woofer and 8th order slopes, one could push this down a bit further, perhaps an ocatave lower. Theoretically, one could even cross a 21" woofer to a large format 2" horn at it's cut-off frequency and still easily avoid excessive beaming, although steep 8th order acoustic slopes would likely be necessary, as with the 18" system, due to the inherent 4th order high-pass of the horn, and natural cutoff of the 21" woofer might require some tricks while attempting to match phase, just like any other loudspeaker system, although I've seen many 21" woofers with relatively smooth on-axis response up to 2 KHz.
With 15's and 12's mated to 2" exit drivers, one can cross an octave or so higher while using shallower slopes and differing xo frequencies to attempt to match them while ending up with a smooth response, but this is all very driver dependent and seems very tricky, at least for me.
Personally, I've never liked steep crossover slopes, but with horns and high SPL, it's pretty much mandatory. No 2nd order acoustic slopes here. So, with all of this said, I was just debating the sacrifice of having to use 8th order acoustic slopes with all their nasty ringing (which becomes even more apparent at high volume levels IME). However, it seems as though this approach of using the horn's high-pass would be a much easier task than attempting to cross an octave or more above it. Simply add a 4th order high-pass to the horn's existing 4th order high-pass to end up with an 8th order acoustic slope, and 8th order low-pass on the woofer (or 7th might work, due to the woofer's inherent roll off). This seems much easier to me than crossing well above the horn's cut off frequency and trying to match phase response and everything of both drivers. At this point, though, I question crossing at the horn's cut-off frequency. What negative effects would this cause? For example..
..Why? I'm curious about things like this. What specific role does the size of the mouth of a horn play?
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If the horn mouth is too small, it doesn't help directivity, hence no boosting due to controlling dispersion. The wavefront is simply too large to be controlled. You also get impedance peaks. Some say you can get weird stuff, but I've no clue.
People can and do run smaller drivers crossed even lower, but to me that would overwork the poor 2" driver. Avante-garde rolls off slower, and they need a larger horn compared to what you need with a 24db crossover. You can play with phase and all that, 24db electrical with sliding the drivers back and forth till it snaps in, works fine for me. I think 6db stuff (like thiels) or multiple full range drivers are great, but at the end of the day, I like my setup better.
Oh yes, and when the frequencies get high (a large horn unloads up high), distortion increases. see page 3 of this jbl pdf comparing their horn to the ev hp640. Notice the distortion increasing as freq goes up. And notice the better dispersion of the hp940 right out to 16khz while the 2380 loses dispersion past 8khz.
http://www.jblpro.com/catalog/support/getfile.aspx?docid=298&doctype=3
Some cd (constant directivity = fairly stable dispersion through frequencies) horns open from the mouth to the sides pretty straight (like a conical).
Most of us pick horns based on dispersion and sound quality (lack of echos).
I try to cross my horn where the directivity open up (where the horn isn't loading the driver as well). My horn vertically starts to lose pattern control below 3khz.
http://archives.telex.com/archives/EV/Horns/EDS/HR90 EDS.pdf
I've played with my crossover points, and 750 sounded better than 1khz. But if I crossed at 1khz, I could go bunchs louder. Maybe more of the highs are horn loaded, or maybe a crossover point further from 2khz, who knows.
Here is a 3mB comparison of 16 horns.
forums.melaudia.net/attachment.php?aid=1760
Notice freq response. Compression drivers roll-off past 2khz (or higher) due to their inductance. The wave plane response graph is what a driver will do without a horn (look for it). Different horns make the driver seem like it has hore high end. Most horns are tractrix / exponential, they narrow the dispersion as the freq goes up. It boosts the high end but only on axis. That may sound weird 10' or more in a room. This document is a lot to swallow, so take your time. To sum it up, the stereo lab horns sound very good with the avante-garde and the l'cleach horns as best. Conical is known to be the least damaging (least echos), but you have to treat the mouth reflections, and they don't load well down low. Paul Klipsch swore by tractrix over exponential profile. Tractrix is said to best keep the expanding wavefront intact.
But to me, the geddes horn may be the best availiable.
http://www.gedlee.com/Loudspeakers.htm
or the 18sound 1.4" cd horn (no corners), i think they have a 2" horn also.
http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=177
Norman
People can and do run smaller drivers crossed even lower, but to me that would overwork the poor 2" driver. Avante-garde rolls off slower, and they need a larger horn compared to what you need with a 24db crossover. You can play with phase and all that, 24db electrical with sliding the drivers back and forth till it snaps in, works fine for me. I think 6db stuff (like thiels) or multiple full range drivers are great, but at the end of the day, I like my setup better.
Oh yes, and when the frequencies get high (a large horn unloads up high), distortion increases. see page 3 of this jbl pdf comparing their horn to the ev hp640. Notice the distortion increasing as freq goes up. And notice the better dispersion of the hp940 right out to 16khz while the 2380 loses dispersion past 8khz.
http://www.jblpro.com/catalog/support/getfile.aspx?docid=298&doctype=3
Some cd (constant directivity = fairly stable dispersion through frequencies) horns open from the mouth to the sides pretty straight (like a conical).
Most of us pick horns based on dispersion and sound quality (lack of echos).
I try to cross my horn where the directivity open up (where the horn isn't loading the driver as well). My horn vertically starts to lose pattern control below 3khz.
http://archives.telex.com/archives/EV/Horns/EDS/HR90 EDS.pdf
I've played with my crossover points, and 750 sounded better than 1khz. But if I crossed at 1khz, I could go bunchs louder. Maybe more of the highs are horn loaded, or maybe a crossover point further from 2khz, who knows.
Here is a 3mB comparison of 16 horns.
forums.melaudia.net/attachment.php?aid=1760
Notice freq response. Compression drivers roll-off past 2khz (or higher) due to their inductance. The wave plane response graph is what a driver will do without a horn (look for it). Different horns make the driver seem like it has hore high end. Most horns are tractrix / exponential, they narrow the dispersion as the freq goes up. It boosts the high end but only on axis. That may sound weird 10' or more in a room. This document is a lot to swallow, so take your time. To sum it up, the stereo lab horns sound very good with the avante-garde and the l'cleach horns as best. Conical is known to be the least damaging (least echos), but you have to treat the mouth reflections, and they don't load well down low. Paul Klipsch swore by tractrix over exponential profile. Tractrix is said to best keep the expanding wavefront intact.
But to me, the geddes horn may be the best availiable.
http://www.gedlee.com/Loudspeakers.htm
or the 18sound 1.4" cd horn (no corners), i think they have a 2" horn also.
http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=177
Norman
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A while ago now did you progress this and how did you get on with either of these?
Thanks
DM
Yes, it has been a long time.
Well, my wife loves them.
She had a large hand in the aesthetics of the design. I covered them in koa veneer and a gray grill cloth held on by magnets. They are large, plain, but still fit well with the decor.
As for performance, these sound best when the volume is turned up. The drivers are unflappable. To my ear the sound is even across the spectrum and the Beymas are sweet and transparent. I use a 50 WPC tube amp to drive these.
First, my room is a bass sink. This is Florida and tile rules. They only practical solution is multiple subs, but there is little room for that, so they play solo.
Getting an accurate measurement from these is a nightmare. It's nearly impossible to work in the limited space we have and such a live environment. The size and weight of these suckers makes it unrealistic to move them outdoors or to some place with proper acoustics. So, I don't have a convincing plot to give you as far as response goes.
That means there are two potential problems with the design:
1. I can't honestly tell you what the lower end frequency response it. In theory is should be good, but the room negates any effort to characterize the response.
2. The Beyma ribbon tweeters beam. I had thought to buy the horns that normally come with them. This would give me a little more lower midrange out of them and a wider horizontal dispersion.
However, the horn actually loses vertical dispersion (according to the data sheets) over the plain Beyma.
This is exactly the wrong thing to do for the Beyma. Without the horn the Beyma vertical dispersion is already narrow, too narrow by my opinion, without a horn. You really need these to be at ear level, then the high end springs to life as well as the overall sound stage.
I have considered trying my hand at building my own horn with the idea of expanding the vertical dispersion. I don't know if that is possible and maybe one day I will but a Beyma with the horn to test that idea.
Otherwise, if I could build the cabinets again I would probably can't the front of cabinet where the tweeter is, back a few degrees to raise the sweet spot up a little. As it is now, sitting on a sofa puts the listener a little too high up for optimum listening. If Beyma could somehow increase the vertical dispersion I think they would have a real winner of a ribbon tweeter.
Well, my wife loves them.
She had a large hand in the aesthetics of the design. I covered them in koa veneer and a gray grill cloth held on by magnets. They are large, plain, but still fit well with the decor.
As for performance, these sound best when the volume is turned up. The drivers are unflappable. To my ear the sound is even across the spectrum and the Beymas are sweet and transparent. I use a 50 WPC tube amp to drive these.
First, my room is a bass sink. This is Florida and tile rules. They only practical solution is multiple subs, but there is little room for that, so they play solo.
Getting an accurate measurement from these is a nightmare. It's nearly impossible to work in the limited space we have and such a live environment. The size and weight of these suckers makes it unrealistic to move them outdoors or to some place with proper acoustics. So, I don't have a convincing plot to give you as far as response goes.
That means there are two potential problems with the design:
1. I can't honestly tell you what the lower end frequency response it. In theory is should be good, but the room negates any effort to characterize the response.
2. The Beyma ribbon tweeters beam. I had thought to buy the horns that normally come with them. This would give me a little more lower midrange out of them and a wider horizontal dispersion.
However, the horn actually loses vertical dispersion (according to the data sheets) over the plain Beyma.
This is exactly the wrong thing to do for the Beyma. Without the horn the Beyma vertical dispersion is already narrow, too narrow by my opinion, without a horn. You really need these to be at ear level, then the high end springs to life as well as the overall sound stage.
I have considered trying my hand at building my own horn with the idea of expanding the vertical dispersion. I don't know if that is possible and maybe one day I will but a Beyma with the horn to test that idea.
Otherwise, if I could build the cabinets again I would probably can't the front of cabinet where the tweeter is, back a few degrees to raise the sweet spot up a little. As it is now, sitting on a sofa puts the listener a little too high up for optimum listening. If Beyma could somehow increase the vertical dispersion I think they would have a real winner of a ribbon tweeter.
I have never used that driver. I have no idea if it would have a wider dispersion than the Beyma, which is my primary issue with my build.
As far as bass response goes, I've tried other speakers cabinets and seen the same issue of attenuated bass response I'm my room, so I am pretty sure that is my room acoustics.
As far as bass response goes, I've tried other speakers cabinets and seen the same issue of attenuated bass response I'm my room, so I am pretty sure that is my room acoustics.
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