Pretty typical for a 'vintage' prosound vented mid-bass for small scoop bins or 1:1 CR, expo flare FLHs. I assume it doesn't have much usable excursion, so with a low Fs-high Vas, not really a TH candidate except in a very large cab, though a T-TQWT should work well in considerably < 320 L with the trade-off of course being less acoustic efficiency/peak SPL. Not many 'free lunches' in audio.
GM
Hi GM,
Interesting, I figured to get the Mmd down that low the voice coil would have to be light in addition to a light weight diaphragm.
Looking at the T/S parameters some more: the Re=8 Ohm looks like somebody type in a nominal value, and the Sd=460 cm^2 is smaller than I would expect for a 12" driver. Both parameters have a strong influence on the simulation.
But Skiivari can measure all of the above to arrive at data that he can trust.
Regards,
Interesting, I figured to get the Mmd down that low the voice coil would have to be light in addition to a light weight diaphragm.
Looking at the T/S parameters some more: the Re=8 Ohm looks like somebody type in a nominal value, and the Sd=460 cm^2 is smaller than I would expect for a 12" driver. Both parameters have a strong influence on the simulation.
But Skiivari can measure all of the above to arrive at data that he can trust.
Regards,
Hello guys.
I gave up on the mentioned driver and any type of horn.
Now I got 2 eminence 6½'s from my friend. The model doesn't read on the back and It isn't any one of the newer eminence 6½'s mentioned on their site. What they most resemble is the closed basket 6½ except they have an open basket.
Specs are: (Self measured
)
Fs= 76hz
Qms= 6.77, Qes=0.82, Qts= 0.73
Sd~~ 123 sq cm
Vas with 123 sd = 9.77l
CMS=4.53E-07(?) I have used E-04 in the sims as I think the spreadsheet has it in mm or something..
It doesn't really want to go much under 37ish hz in a nicely sized enclosure. I'm fine with this. 75l seems to be a sort of optimum one.
One question: is there a problem with going up to 120hz on a sub if it's corner loaded? Don't the sound waves start getting all directional etc?
I gave up on the mentioned driver and any type of horn.
Now I got 2 eminence 6½'s from my friend. The model doesn't read on the back and It isn't any one of the newer eminence 6½'s mentioned on their site. What they most resemble is the closed basket 6½ except they have an open basket.
Specs are: (Self measured
)Fs= 76hz
Qms= 6.77, Qes=0.82, Qts= 0.73
Sd~~ 123 sq cm
Vas with 123 sd = 9.77l
CMS=4.53E-07(?) I have used E-04 in the sims as I think the spreadsheet has it in mm or something..
It doesn't really want to go much under 37ish hz in a nicely sized enclosure. I'm fine with this. 75l seems to be a sort of optimum one.
One question: is there a problem with going up to 120hz on a sub if it's corner loaded? Don't the sound waves start getting all directional etc?
Hi Skiivari,
Your T/S values (Re=?) look reasonable in Hornresp. I end up with a 70L tapped horn.
As to the corner placement, it depends on your setup. E.g.: if you have two corners symmetrically aligned behind your main speakers, and two subwoofers the time alignment would be more of a concern than the cut-off frequency. I'd play it by ear.
Regards,
Your T/S values (Re=?) look reasonable in Hornresp. I end up with a 70L tapped horn.
As to the corner placement, it depends on your setup. E.g.: if you have two corners symmetrically aligned behind your main speakers, and two subwoofers the time alignment would be more of a concern than the cut-off frequency. I'd play it by ear
.Regards,
Attachments
HI Skiivari,
If you change your mind you could try a T-TQWT....In agreement with GM wrote in post# 3722:
b
PS:You mentioned earlier the IR for your FLH. Agree it looks bad. You can compare the wavelets in the submitted picture. In reality the T-TQWT uses damping materials in the path of the tapering resulting in a measured IR that would be superior to your HR FLH simulation too.
Attachments
Hi 454Casull,
There are some folding suggestions, etc. in this thread:
http://www.diyaudio.com/forums/subwoofers/198056-th-t-tqwp.html
Regards,
There are some folding suggestions, etc. in this thread:
http://www.diyaudio.com/forums/subwoofers/198056-th-t-tqwp.html
Regards,
IMO, Thats a layman's opinion based on visual interpretation of an IR that cannot be deduced without slicing up the response in pieces and that must be evaluated with psycho acoustical scales if to be of any value.
What's wrong with the IR?
b
I don't have access to Hornresp right now but there is no positive portion to the waveforum, IIRC.IMO, Thats a layman's opinion based on visual interpretation of an IR that cannot be deduced without slicing up the response in pieces and that must be evaluated with psycho acoustical scales if to be of any value.
What's wrong with the IR?
b
If you look at this in-room measurement of my TH driven by a 2.1 amp based on LM something used in crapola devices.
http://img263.imageshack.us/img263/9861/ircompare.png
Where is the oh so bad IR from a TH?
Compared to an ideal Q0.577 simulated with a rolloff at 30Hz
Hornresps imported IR is not far of when lowpassed the same way.
The point is that you have to low-pass the IR to get anything meaningful out of it, else you are chasing ghosts.
http://img263.imageshack.us/img263/9861/ircompare.png
Where is the oh so bad IR from a TH?
Compared to an ideal Q0.577 simulated with a rolloff at 30Hz
Hornresps imported IR is not far of when lowpassed the same way.
The point is that you have to low-pass the IR to get anything meaningful out of it, else you are chasing ghosts.
Attachments
After a productive morning reading this thread
Overall diameter: 215mm (8.5-inch)
Sensitivity: 87dB (2.83V/1m)
Mms: 31.5g
Cms: 454 um/N
BL: 5.99 T*m
Voice coil diameter: 35.55mm (1.4-inch)
Impedance: 4 Ohm
DC Resistance: 3.4 Ohm
Fs: 40Hz (free air)
Qms: 7.35
Qes: 0.693
Qts: 0.765
Xmax: 8.5mm (one way)
Vas: 26L
Sd: 0.02 m 2
I'm looking for a relatively small tapped horn if possible, that can reach under 30Hz (20 if possible) I'm hoping a small footprint and tall enclosure will have sufficient WAF!
I have a couple of other options in 8" drivers if that isn't suitable (but reading this thread I hope it is).
I am running both Akabak and hornresp on Ubuntu using VMWare Player.
Seems like everyone is buying Macs these days, and I don't imagine that Akabak will ever get ported to OS X, or even Windows 7!
So VMWare Player is absolutely great for this stuff.
I'd argue it's the other way around. Tapped horns aren't necessarily louder than front loaded horns. They're simply a novel way to horn load a woofer without using a huge box.
IE, due to Hoffman's Iron Law the efficiency between the two is comparable, but tapped horns give us the luxury of making the enclosure smaller than would be practical with a FLH.
A few years ago I used to argue on this forum that the TH *was* more efficient, but I no longer believe that is the case.
Oddly enough, one could argue that a sealed box is superior for infrabass than a tapped horn. So a tapped horn's best place to shine may be the range from about 40 to 160hz, oddly enough.
Front and rear loaded horns are designed around a 1/4 wave, while tapped horns use 1/2 wave. Therefore the tapped horn is theorically bigger. Ironically, the RLH has the peak resonance at its 1/2 wave. Basically, I'd say it's a cheat to say that RLH are based on 1/4 wave
. Per exemple, a JBL 4520 has 1/4 wave at 35Hz, but the real bump (1/2 wave) is at 70Hz, where it has the highest output.