I believe the efficiency is more if I understand correctly.
If I'm not mistaken, it's more like an undersized conical horn where a trick is used (the tap) to overcome the peaky response that would normally result. I believe a transmission line achieves a moderate improvement over a vented box in accuracy, but comparable output, but a tapped horn should create significantly more oomph. Apparenly the Danley tapped horn has more output than the contrabass to the tune of 10 db. The Contrabass used 2x high excursion 15" with two 18" PRS. This does more with a single 12" driver.
If I'm not mistaken, it's more like an undersized conical horn where a trick is used (the tap) to overcome the peaky response that would normally result. I believe a transmission line achieves a moderate improvement over a vented box in accuracy, but comparable output, but a tapped horn should create significantly more oomph. Apparenly the Danley tapped horn has more output than the contrabass to the tune of 10 db. The Contrabass used 2x high excursion 15" with two 18" PRS. This does more with a single 12" driver.
paulspencer said:
Because that (manufacturer) opinion might prevent damaging the system?
paulspencer said:
Unless much has changed since I asked (Brian) years ago, it's unsuitable for dipole use also.
I'm not trying to discourage you from trying it all, you paid for them, so they are yours to do with as you wish. I'm simply letting you know that the manufacturer has advised me previously against this. It might be based on his knowledge of his product or perhaps he was just being cautious.
Best of luck with your experiments, I'll keep an eye on them to see how they turned out.
BTW, which Rythmik kit did you get? He seems to have expanded the choices quite a bit.
cheers,
AJ
G'day Rick
>On that note, what distance from the mouth were your measurements taken at?
The published graphs were taken with the microphone in the center of the plane of the mouth. The plots were taken indoors, and this was done to eliminate the effects of the room.
>Also, horns as a rough rule of thumb if I understand correctly add 5 – 7 dB ~ don't know if this applies to bass horns.
Yep, 5-10 dB gain seems reasonable.
>What about tapped horns; what is the db or watts scale on your graphs?
All the horns I measured measured between 95dB/2.8V/M and about 102dB/2.8V/M. As the mouth size goes up the efficiency goes up too. You get less efficiency than Hornresponse predicts.
With the right driver, the dip between the first two peaks will be eliminated.
Cheers
William Cowan
>On that note, what distance from the mouth were your measurements taken at?
The published graphs were taken with the microphone in the center of the plane of the mouth. The plots were taken indoors, and this was done to eliminate the effects of the room.
>Also, horns as a rough rule of thumb if I understand correctly add 5 – 7 dB ~ don't know if this applies to bass horns.
Yep, 5-10 dB gain seems reasonable.
>What about tapped horns; what is the db or watts scale on your graphs?
All the horns I measured measured between 95dB/2.8V/M and about 102dB/2.8V/M. As the mouth size goes up the efficiency goes up too. You get less efficiency than Hornresponse predicts.
With the right driver, the dip between the first two peaks will be eliminated.
Cheers
William Cowan
An interesting idea...
I wonder if there is any real gain here... ?
gain over a 1/4 pipe? (for the freqs the pipe works)
Also, I wonder about the pressures on the drivers - especially the one that happens to be out of phase with the other at any given freq... thinking about the relationship between the peaks of the "main driver" being filled in by the "other driver"...
Also, it's a big box for 30Hz.
What's the relative differential with a 15" driver with the right specs in a similarly sized volume ported cabinet?
How about compared to one of the many bandpass cabinets?
...thinking out loud.
_-_-bear
I wonder if there is any real gain here... ?
gain over a 1/4 pipe? (for the freqs the pipe works)
Also, I wonder about the pressures on the drivers - especially the one that happens to be out of phase with the other at any given freq... thinking about the relationship between the peaks of the "main driver" being filled in by the "other driver"...
Also, it's a big box for 30Hz.
What's the relative differential with a 15" driver with the right specs in a similarly sized volume ported cabinet?
How about compared to one of the many bandpass cabinets?
...thinking out loud.
_-_-bear
AJ are you suggesting that this might destroy the Rythmik driver or amp or servo board?
I'll have to see what Brian has to say. As I understand, the main issue is getting the servo board to understand the frequency response so it can get it right in the nearfield. It may be some time til I settle on something that I'm happy to stick with for a while. A lot of "try things out" urges to use up first.
Bear, this is more like an 18 Hz horn with the right driver. The output should be more than a TL and distortion lower due to efficiency gain. Also the second driver is not what fills in the gaps, it is the fact that the rear output from each driver which is near the mouth loads the horn as a 1/2 wave horn - it does this by virtue of the fact that radiates from the mouth back into the throat, then back again. Effectively this allows the driver to behave differently across the frequency range in such a way that it overcomes the shortcomings of a too-small horn. I've tried sims of bandpass subs with my drivers and I haven't been able to model any significant advantage, even with a size-no-object box.
Will be very interesting to see how things turn out. The results here could either inspire or deter many other attempts.
I'll have to see what Brian has to say. As I understand, the main issue is getting the servo board to understand the frequency response so it can get it right in the nearfield. It may be some time til I settle on something that I'm happy to stick with for a while. A lot of "try things out" urges to use up first.
Bear, this is more like an 18 Hz horn with the right driver. The output should be more than a TL and distortion lower due to efficiency gain. Also the second driver is not what fills in the gaps, it is the fact that the rear output from each driver which is near the mouth loads the horn as a 1/2 wave horn - it does this by virtue of the fact that radiates from the mouth back into the throat, then back again. Effectively this allows the driver to behave differently across the frequency range in such a way that it overcomes the shortcomings of a too-small horn. I've tried sims of bandpass subs with my drivers and I haven't been able to model any significant advantage, even with a size-no-object box.
Will be very interesting to see how things turn out. The results here could either inspire or deter many other attempts.
Greets!
FWIW, I visited DSL the other day to see the 'container' tapped horn, but unfortunately they were behind schedule due to stuff beyond their control, so didn't get a chance to experience forty horn loaded sub drivers, though a quickie audition of some their products using action scenes from 'Spider-man 2' left no doubt that the T-O-P delivers eyeball flattening bass in spades..........
GM
FWIW, I visited DSL the other day to see the 'container' tapped horn, but unfortunately they were behind schedule due to stuff beyond their control, so didn't get a chance to experience forty horn loaded sub drivers, though a quickie audition of some their products using action scenes from 'Spider-man 2' left no doubt that the T-O-P delivers eyeball flattening bass in spades..........
GM
Greets!
Didn't have any, I mean I haven't heard the CB in years and my acoustic space is maybe 1/20 what the TOPs are in. WRT SQ, I was very disappointed, but I'm not familiar with either of the pieces used to demo plus there were lots of other speakers, tapped horns scattered around in close proximity to act as various BW passive radiators, so I'm sure the system has much more potential than I heard.
Really, what impressed me most was the Unitys. The movie scene where lasers? zap the pellet were so clear, razor sharp and dynamic I looked down at my chest, it speared me so hard, realistically, like a small caliber gunshot wound. I'm looking forward to getting my system going again to see how the Altecs fare.
GM
Didn't have any, I mean I haven't heard the CB in years and my acoustic space is maybe 1/20 what the TOPs are in. WRT SQ, I was very disappointed, but I'm not familiar with either of the pieces used to demo plus there were lots of other speakers, tapped horns scattered around in close proximity to act as various BW passive radiators, so I'm sure the system has much more potential than I heard.
Really, what impressed me most was the Unitys. The movie scene where lasers? zap the pellet were so clear, razor sharp and dynamic I looked down at my chest, it speared me so hard, realistically, like a small caliber gunshot wound. I'm looking forward to getting my system going again to see how the Altecs fare.
GM
.
Well your ceiling height is spot on the height of the TOP, so I'd imagine you could just make it just shy of those dimensions to fit your room if standing it up. Should do better than 30 Hz. I can't recommend any driver yet, except point to William's results in which the car version of the old XLS performs well. Richard found driver recommendations I believe - not sure of the source - he might like to chime in. I'll leave other advice to William since he has runs on the board on this one. So far I just have ideas that I haven't yet tested.
Actually I can't really recommend this type of sub yet, not having heard it myself, and not having tried it yet.
Actually I can't really recommend this type of sub yet, not having heard it myself, and not having tried it yet.
“Richard found driver recommendations I believe - not sure of the source - he might like to chime in.”
I’m sure I saw these posted by William, in a thread here
William am I right?
Will the benefit of two XLSs (apart from, if wired in parallel a likely + 6dB) be how much less distortion do you think?
I’m sure I saw these posted by William, in a thread here
William am I right?
Will the benefit of two XLSs (apart from, if wired in parallel a likely + 6dB) be how much less distortion do you think?
G'day Paul
The 830515 car XLS driver is a VERY POOR performer in my 30Hz tapped horn. The graphs on my webpage were labeled incorrectly. This was pointed out and rectified last week. The 830500 worked much better.
Rick
Running a pair of drivers, facing in oposite directions, will yield a very worthwhile improvement in distortion, at a given level. Each driver will have half the excursion, and the even order modes will nearly cancel out. This is good in a final implimentation, but I would not recommend running dual drivers in Paul's test box. This will only complicate the issue.
Cheers
William Cowan
The 830515 car XLS driver is a VERY POOR performer in my 30Hz tapped horn. The graphs on my webpage were labeled incorrectly. This was pointed out and rectified last week. The 830500 worked much better.
Rick
Running a pair of drivers, facing in oposite directions, will yield a very worthwhile improvement in distortion, at a given level. Each driver will have half the excursion, and the even order modes will nearly cancel out. This is good in a final implimentation, but I would not recommend running dual drivers in Paul's test box. This will only complicate the issue.
Cheers
William Cowan
Oops. Glad to hear it actually! We'll have the one that works well, and since it looks like AV12 in hornresp, that's a good sign.
I'm not sure I understand why you don't recommend dual drivers in the test box? Could you elaborate a little more?
I was hoping to reduce the vibration so bracing is less critical, and be able to then brace the test box and improve it a little and have a useable box, rather than having to scrap it and build from scratch. If I allow for 2 drivers in the test box, I could experiment with one or two drivers driven.
I'd also be interested to hear your subjective thoughts on your tapped horns vs other subs.
G'day again Paul
I think the first tapped horn you build should be as simple as possible to maximise your chances of success. If you build your horn according to "plan A" I think your chance of success is very high. Two drivers will need a bigger box.
>I'd also be interested to hear your subjective thoughts on your tapped horns vs other subs.
Lots of output. Very low distortion because of excellent cone control. I was unable to upset the drivers with the full output from an AM1600. The big horn plumbed the depths with more ferocity than any other sub I've experienced. Even an 800L dual 2245H vented box couldn't get close to the big tapped horn for sheer low frequency grunt. Wherever I placed the mouth of the horn the gyprock on the walls would come loose and start banging against the studs.
Tom's fireworks recording was simply jaw dropping with this sub running under my Unity system. The sub integrated seamlessly in my very high resolution system.
It was big, very big, but had a small foot print when standing up. The big tapped horn has been dismantled. The 30Hz horn gets used in the workshop.
Cheers
William Cowan
I think the first tapped horn you build should be as simple as possible to maximise your chances of success. If you build your horn according to "plan A" I think your chance of success is very high. Two drivers will need a bigger box.
>I'd also be interested to hear your subjective thoughts on your tapped horns vs other subs.
Lots of output. Very low distortion because of excellent cone control. I was unable to upset the drivers with the full output from an AM1600. The big horn plumbed the depths with more ferocity than any other sub I've experienced. Even an 800L dual 2245H vented box couldn't get close to the big tapped horn for sheer low frequency grunt. Wherever I placed the mouth of the horn the gyprock on the walls would come loose and start banging against the studs.
Tom's fireworks recording was simply jaw dropping with this sub running under my Unity system. The sub integrated seamlessly in my very high resolution system.
It was big, very big, but had a small foot print when standing up. The big tapped horn has been dismantled. The 30Hz horn gets used in the workshop.
Cheers
William Cowan
G'day William - -my lack of mobility, tools & help are a hinderance but gotta get something better than Klipschorns - K-H sound kinda like BP plus a bit of non-coherent old-school PA.
Karlson coupler = stubborn pick of midbass over reflex and some horn as cone excursion is controlled at high peak outputs. Drums are great. I briefly ran one Unity passively xovered to an 18"K but may use 15" coupler with K-tube - if can guess a smooth playing front section from previous observations.
I don't know if bass k-couplers are practical although exemplar chose to re-tune and boost K15 with an ALtec 15 and subjectively that's pretty good.
does your little 30Hz Peerless TH play extremely taut once xover is dialed in?
Best,
Freddy
Karlson coupler = stubborn pick of midbass over reflex and some horn as cone excursion is controlled at high peak outputs. Drums are great. I briefly ran one Unity passively xovered to an 18"K but may use 15" coupler with K-tube - if can guess a smooth playing front section from previous observations.
I don't know if bass k-couplers are practical although exemplar chose to re-tune and boost K15 with an ALtec 15 and subjectively that's pretty good.
does your little 30Hz Peerless TH play extremely taut once xover is dialed in?
Best,
Freddy