Re: Re: Re: Want to build my first TH
Hi Steve,
if you want to build some of my stuff - just go ahead, I'd appreciate that.
ATM, I only have a 18dB/oct Albs Sub-25 subwoofer x-over. A steeper slope is required for the large TH to match perfect to the conical midbass.
What I noticed was that the channel, where the large TH was located behind, sounded larger/fuller with more body. Actually I liked that, but this shifted the "weight" to the side where the TH is placed (which was not acceptable for me).
The smaller TH's were only built out of curiosity. Actually I like them a lot. They made the Klipschorn superfluous. The Tangband TH's are much easier to integrate to the conical midbass.
In the next couple of weeks I will remove the KH from my living room. May be I also will get back to the idea you now have as well: Building a second one of the large TH to see if this helps to iron out the response (having some nasty room modes at 35 & 40Hz).
At the moment the x-over point from the large to the small TH's is in this region of the room modes which provides the possibility to cover the problem a little. Most likely there is some potential to increase performance but I simply do not find the time for measurement and tweaking.
Erik
steve71 said:
Hi Steve,
if you want to build some of my stuff - just go ahead, I'd appreciate that.
ATM, I only have a 18dB/oct Albs Sub-25 subwoofer x-over. A steeper slope is required for the large TH to match perfect to the conical midbass.
What I noticed was that the channel, where the large TH was located behind, sounded larger/fuller with more body. Actually I liked that, but this shifted the "weight" to the side where the TH is placed (which was not acceptable for me).
The smaller TH's were only built out of curiosity. Actually I like them a lot. They made the Klipschorn superfluous. The Tangband TH's are much easier to integrate to the conical midbass.
In the next couple of weeks I will remove the KH from my living room. May be I also will get back to the idea you now have as well: Building a second one of the large TH to see if this helps to iron out the response (having some nasty room modes at 35 & 40Hz).
At the moment the x-over point from the large to the small TH's is in this region of the room modes which provides the possibility to cover the problem a little. Most likely there is some potential to increase performance but I simply do not find the time for measurement and tweaking.
Erik
I'm also interested in building large/small THs for the bottom two octaves in an otherwise FLH system.
Two each (one for each side) though.
I'll also probably also just copy yours since you already did the work of coming up with a pair of working designs.
(Thanx!
)
Do you notice any time delay/ phase problems with the THs?
I haven't decided on flare for mid bass horn, but am leaning toward exponential.
Do you like the conical better than the tractrix you had?
What lead to that choice?
Thanx,
Robert
Two each (one for each side) though.
I'll also probably also just copy yours since you already did the work of coming up with a pair of working designs.
(Thanx!
) Do you notice any time delay/ phase problems with the THs?
I haven't decided on flare for mid bass horn, but am leaning toward exponential.
Do you like the conical better than the tractrix you had?
What lead to that choice?
Thanx,
Robert
serenechaos said:
Hi Robert,
in my case I'm a little uncertain whether or not there is a phase issue buried. In the beginning I tried back and forth in regards to polarity of the large TH. Now I use it in phase with the smaller ones. It may be a little difficult to decide because I have a room mode at the x-over frequency. Things would be more clear if I would do some measurements. To be honest I'm not an expert in that. Especially in the lowest registers it is not a trivial task to interprete results correctly.
On the other hand, it seems the better the system gets the more sensitive it is to bad recordings. I think I will change to an active setup some time in future.
Problem right now is that the digital xovers (like the DCX2494) need to be driven with full volume all the time, which is not possible with the preamplifier/decoder I have (I do use the decoder/input selector and volume control only of my Yamaha AX-1 because the Trends T-Amp sounds beter for me).
serenechaos said:
The main reason was to ease the building process and because from a simulation standpoint of view, there was only a very small advantage for the hyperbolic contur (which was my favorite at first)
Read more on that here.
Erik
How much different does the conical sound than the tractrix?
Is it better, or different, or just more in the right range?
Every conical I've heard has a strange coloration to it.
Tractrix have sounded good, but I've heard that they don't load as well in the low end. That's why I was going to go with expo or hypo for mid bass, but it's so long...
decisions, decisions...
Thanx again,
Robert
Is it better, or different, or just more in the right range?
Every conical I've heard has a strange coloration to it.
Tractrix have sounded good, but I've heard that they don't load as well in the low end. That's why I was going to go with expo or hypo for mid bass, but it's so long...
decisions, decisions...
Thanx again,
Robert
Re: Re: Re: Re: Want to build my first TH
Thanks Erik and I appreciate your efforts in documenting your builds.
Thanks for the explanation. Sounds like I might be able to get away with one (double folded) TH centrally placed in between the horns. And I can always build another if the need be.
The TH will be actively crossed with a 24db/oct slope or perhaps I'll try to use my AVP's 80hz crossover. I don't know the slope of that x-over, but it has other advantages for movies (sub signal is up 10db).
BTW I'm also using a Trends Audio amp in my setup. They're powering the midrange Altec 288K's /MR-64 horns from 400+ Hz. Great bang for the buck, but I'd love to try a nice SET amp one of these days.
Volvotreter said:
Thanks Erik and I appreciate your efforts in documenting your builds.
Volvotreter said:
Thanks for the explanation. Sounds like I might be able to get away with one (double folded) TH centrally placed in between the horns. And I can always build another if the need be.
The TH will be actively crossed with a 24db/oct slope or perhaps I'll try to use my AVP's 80hz crossover. I don't know the slope of that x-over, but it has other advantages for movies (sub signal is up 10db).
BTW I'm also using a Trends Audio amp in my setup. They're powering the midrange Altec 288K's /MR-64 horns from 400+ Hz. Great bang for the buck, but I'd love to try a nice SET amp one of these days.
A few pages back, I posted a cartoon of a refold of Cowan's 30Hz horn. Now I'm posting a complete plan, so that some of you "fence sitters" might be encouraged to join us. It's for 18mm or 3/4 stock, and with no long panels and lots of corners, you can get by without bracing.
Horns MUST be leak-free. Holes for handles and connector cups can be used as access ports to caulk any leaks. Much of this design can be caulked thru the mouth. Plan to put a connector cup on the "Rear" panel near the "e" on the diagram, this will allow you to caulk "Flare 2" if needed.
This fold will allow Cowan's horn to be transported in many larger cars, either hatch-back, trunk, or back seat. With an 80Hz cross-over, it should be good for HT, Weekend Warrior Bands or DJs.
If your woodworking skills are a little rusty, Rog Mogale has a great tutorial on his site.
http://speakerplans.com/index.php?id=guide
Good Luck (and lots'a bass)
~Don
Horns MUST be leak-free. Holes for handles and connector cups can be used as access ports to caulk any leaks. Much of this design can be caulked thru the mouth. Plan to put a connector cup on the "Rear" panel near the "e" on the diagram, this will allow you to caulk "Flare 2" if needed.
This fold will allow Cowan's horn to be transported in many larger cars, either hatch-back, trunk, or back seat. With an 80Hz cross-over, it should be good for HT, Weekend Warrior Bands or DJs.
If your woodworking skills are a little rusty, Rog Mogale has a great tutorial on his site.
http://speakerplans.com/index.php?id=guide
Good Luck (and lots'a bass)
~Don
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steve, I think we have the same design goals as far as bass goes. If you are wanting to use an 80hz XO point you will probably need to go with the design that Don just posted or something similar. Every 20hz design that I have come across (including the one using the lab12 that I have chosen) does not smoothly go up to 80hz. Thats why I just bought a dcx2496 XO and equalizer to XO at 60hz to my mains. I will be building two of the 20hz tapped horns as soon as possible. I probably could get away with a cutoff of 30hz and use the design just posted, but I want to be able to meet thx ultra 2 specifications if only for bragging rights.
IIRC, Eric built one that had a rather deep notch at the horn's 3rd harmonic Vs one of the alignments that maximizes horn loading over the driver's point source BW, so combined with only having one corner loaded it's a bit much to expect it to integrate well above this point, especially with the channel furthest away.
IOW he really had no choice but to add 'filler' subs since there's no way to properly EQ the deep notch and the 'hash' in the response above it AFAIK and why I prefer having the excess gain BW of horn loading if you don't do it Tom's way of using the right driver for the BW combined with resonators, etc. to smooth/damp its HF for max practical BW.
As always though, YMMV.
GM
IOW he really had no choice but to add 'filler' subs since there's no way to properly EQ the deep notch and the 'hash' in the response above it AFAIK and why I prefer having the excess gain BW of horn loading if you don't do it Tom's way of using the right driver for the BW combined with resonators, etc. to smooth/damp its HF for max practical BW.
As always though, YMMV.
GM
Thanks GM,
I should have said I was planning on using two THs for the first octave, (not just one) and two for the second octave.
Then going to four FLHs to cover about two octaves each.
I haven't been able to find a model which duplicates Toms feat of going from 20 - 100 with just one TH...
Even a smooth 20 - 90 would do, but the higher I could push the TH, the smaller the mid-bass (largest of the four) front horn could be.
(A 60Hz FLH takes up quite a bit of floor space...).
Robert
I should have said I was planning on using two THs for the first octave, (not just one) and two for the second octave.
Then going to four FLHs to cover about two octaves each.
I haven't been able to find a model which duplicates Toms feat of going from 20 - 100 with just one TH...
Even a smooth 20 - 90 would do, but the higher I could push the TH, the smaller the mid-bass (largest of the four) front horn could be.
(A 60Hz FLH takes up quite a bit of floor space...).
Robert
So what part of that graph is usable?
It looks like it doesn't quite get down to 20, and the peaks start @ 70.
Isn't that worse?
How large of a box is this?
(It might be smaller than two boxes to get two octaves).
Thanx,
Robert
edit: you posted volume; I didn't see it @ first.
Do you know Length? Or width?
It looks like it doesn't quite get down to 20, and the peaks start @ 70.
Isn't that worse?
How large of a box is this?
(It might be smaller than two boxes to get two octaves).
Thanx,
Robert
edit: you posted volume; I didn't see it @ first.
Do you know Length? Or width?
I just looked @ the simulation on Eriks site again: http://www.volvotreter.de/pics/TH/EPS15-500_v3_SPL.jpg
The simulation MaVo posted above is just about the same in frequency range, but up by nearly 10dB!
Looks like a good piece to build a pair of, with a notch filter to get rid of the peak from ~70 - 90 Hz.
What driver was this modeled around???
Am I figuring this right:
1 cu. meter volume = 35.31 cu ft.
2.1' x 2.1' x 8' = 35.28 cu ft. (internal, + divider).
So outside dimension would be ~ 26.7" x 27.5" x 97.5"?
(Plus any needed external bracing).
Robert
The simulation MaVo posted above is just about the same in frequency range, but up by nearly 10dB!
Looks like a good piece to build a pair of, with a notch filter to get rid of the peak from ~70 - 90 Hz.
What driver was this modeled around???
Am I figuring this right:
1 cu. meter volume = 35.31 cu ft.
2.1' x 2.1' x 8' = 35.28 cu ft. (internal, + divider).
So outside dimension would be ~ 26.7" x 27.5" x 97.5"?
(Plus any needed external bracing).
Robert
driver is bms 18n860. i would use it to 120hz, since the peaks are alot smaller than what your typical room does to a flat response. with my latest attempt at folding, it would be about 130 * 120 * 68cm in size with the mouth in the 120*68 plane.
here is a sim, but with slightly different parameters for 2PI setup:
here is a sim, but with slightly different parameters for 2PI setup:
Attachments
serenechaos said:
The lab 12 version is good from 20hz to right at 65 hz. But you will need a very steep XO if your going to do it at 65hz. A member of this board has offered to fold the design up for me, and i am hoping to be able to experiment a little bit with resonators to see how well i can attenuate the two peaks. The two lab 12 drivers and the dxc2496 are on their way, so as soon as i get the plans I will have them built fairly quickly.
serenechaos said:
Since I will be building two of them, it will give me a somewhat limited opportunity to experiment with resonators. I will basically have 4 tries to get one of them right, and based on what works and doesn't work, we can more easily predict what will work better for other designs. If we can get them right, then the lab 12 tapped horn will be good up to 100hz or so. Wost case scenario, the resonators will not work as intended, but I wasn't planning to use that bandwidth anyway.
What is wrong with digital XO's? I read through the thread on this board about the dcx2496 and even when compared to a multi thousand dollar professional unit it sounded very nice. Another benefit is that you can eq your system based on how it interacts with your room at no extra cost (not counting a microphone)