Hi Andrew,
Look at the dates of my posts re: eq down to 20's... This was about the first time I'd ever heard of the labhorn project, and I wasn't aware of what the limitations of horn loading were. I've read a lot in the last 2 years since then, and my systems changed a lot too. After the last few posts above I went off and built 3 sealed tempests instead of the labs, but 2 years later I built the labs as the tempests weren't doing it for sound quality for me. (it was the lack of low bass that put me off building the labs. Now I've heard them I wish I'd gone ahead and built them back then)
I actually use 2 tempests below 30Hz, with 2 labs above. (also have another tempest on its way to go with my 3rd to give me a total of 4 to do 30Hz down.)
However
I've read some promising stuff regarding eq'ing a a pair of labs down to the mid 20's - I'm pretty sure Tom Danley has stated that a lab hits x-max at 30Hz at about 1200 - 1500 watts, which leaves a fair bit of headroom to eq it down in a home environment - especially if you're not planning on cinema reference levels. I've never read of anyone blowing a labhorn driver with home use. My measurements show that a single labhorn is still loaded at 30Hz here, rather than the 35Hz you quoted above:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67039&pagenumber=1
Theres also a guy on the avs forum using a pair of b-deaps with eq to acheive significant output to the teens...they use similar / (same?) drivers to the labhorn and I believe their cutoff is slightly higher.
http://archive.avsforum.com/avs-vb/showthread.php?threadid=272320&highlight=leviathon
Just to clear up, personally I'd only eq a labhorn below its cutoff if I was sure that the drivers would stay within their limits. I'm pretty sure that mine would be safe to 25Hz, but choose to cross at 30 as a 12dB slope adds nicely to the natural in-room roll off of the labs and saves me having to mess about for a 5Hz change in xo point.
Cheers,
Rob.
Look at the dates of my posts re: eq down to 20's... This was about the first time I'd ever heard of the labhorn project, and I wasn't aware of what the limitations of horn loading were. I've read a lot in the last 2 years since then, and my systems changed a lot too. After the last few posts above I went off and built 3 sealed tempests instead of the labs, but 2 years later I built the labs as the tempests weren't doing it for sound quality for me. (it was the lack of low bass that put me off building the labs. Now I've heard them I wish I'd gone ahead and built them back then)
I actually use 2 tempests below 30Hz, with 2 labs above. (also have another tempest on its way to go with my 3rd to give me a total of 4 to do 30Hz down.)
However
I've read some promising stuff regarding eq'ing a a pair of labs down to the mid 20's - I'm pretty sure Tom Danley has stated that a lab hits x-max at 30Hz at about 1200 - 1500 watts, which leaves a fair bit of headroom to eq it down in a home environment - especially if you're not planning on cinema reference levels. I've never read of anyone blowing a labhorn driver with home use. My measurements show that a single labhorn is still loaded at 30Hz here, rather than the 35Hz you quoted above:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67039&pagenumber=1
Theres also a guy on the avs forum using a pair of b-deaps with eq to acheive significant output to the teens...they use similar / (same?) drivers to the labhorn and I believe their cutoff is slightly higher.
http://archive.avsforum.com/avs-vb/showthread.php?threadid=272320&highlight=leviathon
Just to clear up, personally I'd only eq a labhorn below its cutoff if I was sure that the drivers would stay within their limits. I'm pretty sure that mine would be safe to 25Hz, but choose to cross at 30 as a 12dB slope adds nicely to the natural in-room roll off of the labs and saves me having to mess about for a 5Hz change in xo point.
Cheers,
Rob.
Rob
> Why not use 1 'normal' lab with a flare extension mono up to 80 Hz ? (Same amount of drivers, less woodwork)
Good idea ~ considered that woodwork saving, but each side of the pair can go into a room corner for extension & being out of the way.
Just one in the middle would fire into glass doors aimed at the neighbour’s bedroom.
> I use 2 tempests below 30Hz, with 2 labs above
I was going to use two EQed Peerless XLS 12s below.
Andrew
> if you delete one driver you will need to extend the horn down to a new smaller throat. About an extra 700 mm. . . .
I feared something like that ~ what are the basic 'physics'?
Maybe long time horner’s Jeff Robinson’s version is the safest bet, though it seems more complicated or detailed than the original. (I wonder what Tom Danley thinks)
Any views on relative job size?
Cheers
Rick
> Why not use 1 'normal' lab with a flare extension mono up to 80 Hz ? (Same amount of drivers, less woodwork)
Good idea ~ considered that woodwork saving, but each side of the pair can go into a room corner for extension & being out of the way.
Just one in the middle would fire into glass doors aimed at the neighbour’s bedroom.
> I use 2 tempests below 30Hz, with 2 labs above
I was going to use two EQed Peerless XLS 12s below.
Andrew
> if you delete one driver you will need to extend the horn down to a new smaller throat. About an extra 700 mm. . . .
I feared something like that ~ what are the basic 'physics'?
Maybe long time horner’s Jeff Robinson’s version is the safest bet, though it seems more complicated or detailed than the original. (I wonder what Tom Danley thinks)
Any views on relative job size?
Cheers
Rick
mono bass off centre
> Why not use 1 'normal' lab with a flare extension mono up to 80 Hz ? (Same amount of drivers, less woodwork)
Good idea ~ but my wife has just vetoed putting it in the centre of the back wall (1/ 4 loading).
So how do people feel it would be, having a single Lab over about 30 – 90 Hz, firing into a corner on one side
of the room? Ie mono (should be no problem) but off centre.
Regards
Rick
> Why not use 1 'normal' lab with a flare extension mono up to 80 Hz ? (Same amount of drivers, less woodwork)
Good idea ~ but my wife has just vetoed putting it in the centre of the back wall (1/ 4 loading).
So how do people feel it would be, having a single Lab over about 30 – 90 Hz, firing into a corner on one side
of the room? Ie mono (should be no problem) but off centre.Regards
Rick
Rick,
Try a search over at PSW on flare extensions. I think theres a post re: single driver flare extension. Something like a shelf that sits on top of the lab, and continues into the corner. Possibly goes into a triangle accross the corner ?
Some people have tried it down firing, 29" off the floor aswell. Not sure how to do a flare extension on that though.
Rob.
Try a search over at PSW on flare extensions. I think theres a post re: single driver flare extension. Something like a shelf that sits on top of the lab, and continues into the corner. Possibly goes into a triangle accross the corner ?
Some people have tried it down firing, 29" off the floor aswell. Not sure how to do a flare extension on that though.
Rob.
Attachments
Greets!
Based on my observations and other's responses over the years on various lists, forums, most folks who responded can localize a single corner loaded 80 Hz XO/4th order point source sub. Distortion components are assumed to be the main reason, so with a compression driven horn's much lower distortion it should in theory sound omni as long as the distance from the corner isn't too far from the furthest listening position. If 90 Hz/4th order is used, then -12 dB will be around 127 Hz, or 8.9 ft away. This isn't very far, so odds are it can be localized if the room's not large/long enough that reflections create a reverberant field down this low.
Only one way to know for sure though.
GM
Based on my observations and other's responses over the years on various lists, forums, most folks who responded can localize a single corner loaded 80 Hz XO/4th order point source sub. Distortion components are assumed to be the main reason, so with a compression driven horn's much lower distortion it should in theory sound omni as long as the distance from the corner isn't too far from the furthest listening position. If 90 Hz/4th order is used, then -12 dB will be around 127 Hz, or 8.9 ft away. This isn't very far, so odds are it can be localized if the room's not large/long enough that reflections create a reverberant field down this low.
Only one way to know for sure though.
GM
Hi
> most can localize a single corner loaded 80 Hz XO/4th order point source sub.
I "feared" as much.
> with a compression driven horn's much lower distortion it should in theory sound omni as long as the distance from the corner isn't too far from the furthest listening position.
What compression driven will play 40 - 100 Hz ? ?
> If 90 Hz/4th order is used,
Yes likely 4th order.
> then -12 dB will be around 127 Hz, or 8.9 ft away.
Interesting theory.
I expect the listener would be about 14-15 feet (about 4.5 m) away. The reverberant field can hopefully be controlled, by about 30 acoustic tiles I just bought in a close out.
Are you suggesting that if the listener is *greater than 9 ft (3 m) away, it would not be localized, and should be ok??
Thanks
> most can localize a single corner loaded 80 Hz XO/4th order point source sub.
I "feared" as much.
> with a compression driven horn's much lower distortion it should in theory sound omni as long as the distance from the corner isn't too far from the furthest listening position.
What compression driven will play 40 - 100 Hz ? ?
> If 90 Hz/4th order is used,
Yes likely 4th order.
> then -12 dB will be around 127 Hz, or 8.9 ft away.
Interesting theory.
I expect the listener would be about 14-15 feet (about 4.5 m) away. The reverberant field can hopefully be controlled, by about 30 acoustic tiles I just bought in a close out.
Are you suggesting that if the listener is *greater than 9 ft (3 m) away, it would not be localized, and should be ok??
Thanks
Greets!
Uh, the LABhorn.
Your room isn't large enough to be reverberant this low.
No, once you're >one WL away you're no longer in its nearfield, so you can in theory detect the phase error between what's coming from the mains and the corner, causing the image to shift somewhat towards the corner.
Depending on the recording, the signal is summed mono below ~120-50 Hz for music and 120 Hz on all movies, so you have three mono sources spread across the room with one being corner loaded (and boosted as required to be +10 dB referenced to the mains for HT), so once in the farfield the only balanced listening position will be in the diagonally opposite 'corner' from the sub. Everyone else gets an increasingly corner biased shift until the furthest channel is all but cancelled out over some portion of its BW.
Since the stereo harmonics that are in our more acute hearing BW are only coming from the mains though, the shift won't sound as obviously offset as when you only play the same BW as the sub through them. Note too that for movies, we're vision centric, so our internal processor tends to 'EQ' out a certain amount of any phasing errors, and one reason why a multitude of surrounds in a cinema or a single phasey dipole in a HT tend to sound like a point source no matter where you're sitting. Listening to music OTOH forces us to focus on the sources since we're either staring at the speakers or have our eyes closed so removing as many phasing errors as practical is paramount.
You're welcome!
GM
rick57 said:
Uh, the LABhorn.
Your room isn't large enough to be reverberant this low.
No, once you're >one WL away you're no longer in its nearfield, so you can in theory detect the phase error between what's coming from the mains and the corner, causing the image to shift somewhat towards the corner.
Depending on the recording, the signal is summed mono below ~120-50 Hz for music and 120 Hz on all movies, so you have three mono sources spread across the room with one being corner loaded (and boosted as required to be +10 dB referenced to the mains for HT), so once in the farfield the only balanced listening position will be in the diagonally opposite 'corner' from the sub. Everyone else gets an increasingly corner biased shift until the furthest channel is all but cancelled out over some portion of its BW.
Since the stereo harmonics that are in our more acute hearing BW are only coming from the mains though, the shift won't sound as obviously offset as when you only play the same BW as the sub through them. Note too that for movies, we're vision centric, so our internal processor tends to 'EQ' out a certain amount of any phasing errors, and one reason why a multitude of surrounds in a cinema or a single phasey dipole in a HT tend to sound like a point source no matter where you're sitting. Listening to music OTOH forces us to focus on the sources since we're either staring at the speakers or have our eyes closed so removing as many phasing errors as practical is paramount.
You're welcome!
GM
GM
>> What compression driven will play 40 – 100
> Uh, the LABhorn.
I thought the original poster was referring to a compression driver, eg a 2” throat JBL. I believe the lowest any compression driver will go is about 300 Hz.
If by compression driven was meant a horn of any kind ie *with compression, there are quite a few, those I know of: www.diyaudio.com/forums/showthread.php?s=&threadid=67852
the LABhorn may have the most output.
Thanks for your *excellent description of the effect of a mono sub. Not a huge compromise, but an undesirable one. Looks like I will have to persuade she who would wish to be obeyed
Cheers
>> What compression driven will play 40 – 100
> Uh, the LABhorn.
I thought the original poster was referring to a compression driver, eg a 2” throat JBL. I believe the lowest any compression driver will go is about 300 Hz.
If by compression driven was meant a horn of any kind ie *with compression, there are quite a few, those I know of: www.diyaudio.com/forums/showthread.php?s=&threadid=67852
the LABhorn may have the most output.
Thanks for your *excellent description of the effect of a mono sub. Not a huge compromise, but an undesirable one. Looks like I will have to persuade she who would wish to be obeyed
Cheers
Greets!
Yes, there's numerous low CR prosound designs available to the DIYer.
There seems to be considerable misunderstanding WRT to what an optimized compression loaded driver is capable of. An Altec, JBL, or similar design 1" unit will work quite well in the 40-100 Hz BW if you make the horn long enough and terminated with a large enough mouth. AFAIK though, no delay unit currently available can come close enough to aligning it with a sub and super tweeter system, so as a system its SQ won't be high enough to justify all your space/$$/effort.
GOTO offers a LF/midbass compression driver, but I gather it's priced right up there with a Mercedes, so not for the impecunious DIYer. Cogent is working on a ~scaled up/tweaked RCA field coil unit with a 6"? diaphragm, but being hand crafted like the GOTO, it won't be cheap, though I gather it will be value priced once available.
Anyway, seems to me that a folded corner horn that runs from ~floor to ceiling would be the way to get some semblance of WAF and 'stereo' subs. The top of the mouth could be designed to be the mounting shelf for the other horns.
GM
Yes, there's numerous low CR prosound designs available to the DIYer.
There seems to be considerable misunderstanding WRT to what an optimized compression loaded driver is capable of. An Altec, JBL, or similar design 1" unit will work quite well in the 40-100 Hz BW if you make the horn long enough and terminated with a large enough mouth. AFAIK though, no delay unit currently available can come close enough to aligning it with a sub and super tweeter system, so as a system its SQ won't be high enough to justify all your space/$$/effort.
GOTO offers a LF/midbass compression driver, but I gather it's priced right up there with a Mercedes, so not for the impecunious DIYer. Cogent is working on a ~scaled up/tweaked RCA field coil unit with a 6"? diaphragm, but being hand crafted like the GOTO, it won't be cheap, though I gather it will be value priced once available.
Anyway, seems to me that a folded corner horn that runs from ~floor to ceiling would be the way to get some semblance of WAF and 'stereo' subs. The top of the mouth could be designed to be the mounting shelf for the other horns.
GM
rick57 said:GM
>> What compression driven will play 40 – 100
> Uh, the LABhorn.
I thought the original poster was referring to a compression driver, eg a 2” throat JBL. I believe the lowest any compression driver will go is about 300 Hz.
I used the Emilar EC600 with the 6" aluminium compression driver and 4" exit with these from 100 Hz up. This was a 5-way fully horn loaded system with compression drivers from 100 Hz up
An externally hosted image should be here but it was not working when we last tested it.
The lower horns on the floor in the picture is how the big compression drivers were loaded. In the background is three 18" woofer down firing horn subs.
I still use the subs.
The driver - they went to 150 cycles in free space in the big horns - and all the way up to 4-5K on top!!!
-----
-----
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The compression driver midbass horn -
Had to get rid of them - they caused too much alcohol abuse.
An externally hosted image should be here but it was not working when we last tested it.
GM
> Anyway, seems to me that a folded corner horn that runs from ~floor to ceiling would be the way to get some semblance of WAF and 'stereo' subs. The top of the mouth could be designed to be the mounting shelf for the other horns.
I was about to write, ok, interesting, but have you thoughts on any of the designs I mentioned (I’m interested if you do)
– then I thought, mmm the horn could be sited with wall height of 10 feet/ 3.2 m.
Maybe that allows a horn with a few less foldings than the “box” folded horn designs I was considering? Or other benefits (eg go a little higher)?
I keep thinking of Pass’s El-Pipe-O, but that’s I recall a transmission line.
Anyone know of longer (eg 10 feet/ 3.2 m) bass horn designs on the web?
Cheers
> Anyway, seems to me that a folded corner horn that runs from ~floor to ceiling would be the way to get some semblance of WAF and 'stereo' subs. The top of the mouth could be designed to be the mounting shelf for the other horns.
I was about to write, ok, interesting, but have you thoughts on any of the designs I mentioned (I’m interested if you do)
– then I thought, mmm the horn could be sited with wall height of 10 feet/ 3.2 m.
Maybe that allows a horn with a few less foldings than the “box” folded horn designs I was considering? Or other benefits (eg go a little higher)?
I keep thinking of Pass’s El-Pipe-O, but that’s I recall a transmission line.
Anyone know of longer (eg 10 feet/ 3.2 m) bass horn designs on the web?
Cheers
Magnetar
> the Emilar EC600 with the 6" aluminium compression driver and 4" exit with these from 100 Hz up. This was a 5-way fully horn loaded system with compression drivers from 100 Hz up
Lucky you!
> Had to get rid of them - they caused too much alcohol abuse
I think I can understand What about hearing loss?
Cheers
> the Emilar EC600 with the 6" aluminium compression driver and 4" exit with these from 100 Hz up. This was a 5-way fully horn loaded system with compression drivers from 100 Hz up
Lucky you!
> Had to get rid of them - they caused too much alcohol abuse
I think I can understand
What about hearing loss?Cheers
rick57 said:Magnetar
> Had to get rid of them - they caused too much alcohol abuse
I think I can understand
Cheers
They were a bit scary at times although a good horn loaded 10-15" woofer can sound every bit as good if not better, and play louder. The compression driver bass was FAST - heck it went out to 4K at around 112 db/watt! The 'speed' caused the drinking problems -----
Also I prefer a good high efficiency 15 loaded in a Karlson Klam like the Altec 921-8LF or ElectroVoice EVM15B - Excellent bass slam and defintion 40-250 Hz in a more compact enclosure.
Greets!
I'm not familiar with any of the designs in this thread beyond reading about them. I typically either used Altec designs or did variations of my own using multiple drivers with XOs as high as 500 Hz like W.E/Altec/JBL did to keep them reasonably compact. For your app, a custom designed single driver two fold corner design seems the 'no-brainer' choice to me. Really, for 40 Hz you can get by with the driver at the extreme top and only the one 90 deg at the mouth. Made triangular, it would be reasonably compact and blend into the cornerpretty good.
Right, 'El Pipe-O' is a straight taper TL.
GM
I'm not familiar with any of the designs in this thread beyond reading about them. I typically either used Altec designs or did variations of my own using multiple drivers with XOs as high as 500 Hz like W.E/Altec/JBL did to keep them reasonably compact. For your app, a custom designed single driver two fold corner design seems the 'no-brainer' choice to me. Really, for 40 Hz you can get by with the driver at the extreme top and only the one 90 deg at the mouth. Made triangular, it would be reasonably compact and blend into the cornerpretty good.
Right, 'El Pipe-O' is a straight taper TL.
GM
GM - you are a 
Again you’ve triggered me rethinking the room layout , with either a long straight horn in the centre (1/4 loading, but no bass offset), or as you say in the corner behind a door (that I’d thought oif as almost dead space) - I think I can squeeze about 300 mm ie 12”, but height and depth are pretty well unrestricted.
A straight horn would still I think be simpler to build, though a two fold design can’t be too hard.
Do you know any links to a two fold or triangular design?
Cheers
Again you’ve triggered me rethinking the room layout
, with either a long straight horn in the centre (1/4 loading, but no bass offset), or as you say in the corner behind a door (that I’d thought oif as almost dead space) - I think I can squeeze about 300 mm ie 12”, but height and depth are pretty well unrestricted. A straight horn would still I think be simpler to build, though a two fold design can’t be too hard.
Do you know any links to a two fold or triangular design?
Cheers
Hi,
an earlier delay compensation comment got me thinking.
If delay due to very long horns becomes a problem and the electronics might have difficulty correcting it, might it be better to shorten the horn?
My sub base horn project is just about to start and the flare doubles in area each 1.4m along the centre line. If I put in 2 drivers then the throat is twice as big and the horn is 1.4m shorter but if I put in 4 drivers then it will be 2.8m shorter.
I do not need the power requirement for a domestic system so this seems wasteful but maybe the pay off will be reduced delay and thereby better sound.
Comments welcome.
an earlier delay compensation comment got me thinking.
If delay due to very long horns becomes a problem and the electronics might have difficulty correcting it, might it be better to shorten the horn?
My sub base horn project is just about to start and the flare doubles in area each 1.4m along the centre line. If I put in 2 drivers then the throat is twice as big and the horn is 1.4m shorter but if I put in 4 drivers then it will be 2.8m shorter.
I do not need the power requirement for a domestic system so this seems wasteful but maybe the pay off will be reduced delay and thereby better sound.
Comments welcome.
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