OK so finally I have done a web page describing this project
Inspiration : a TQWT for Fostex FX120
The digital version of the plan is coming
Inspiration : a TQWT for Fostex FX120
The digital version of the plan is coming
Commenting on your FR plot
The 50 Hz peak is typical of drivers that don't really want to go into TQWT's, or any other resonant cabinet for that matter. EBS BR's work best with these drivers. A bit of damping in the port will fix this.
The ~120 Hz hole is typical of TWQT's. It is the first overtone. More stuffing will help.
The ~180 Hz hole is most likely floor bounce. There is really nothing you can do about this one.
You have generated one of the best examples of baffle step that I have seen. Note that the trend line is ~ -2.5 dB to ~800Hz then it jumps to ~ +2 dB. Something around a 1 mH inductor || 6 ohm resistor is flatten it out. But then, this has aready been addressed earlier in the thread.
Bob
The 50 Hz peak is typical of drivers that don't really want to go into TQWT's, or any other resonant cabinet for that matter. EBS BR's work best with these drivers. A bit of damping in the port will fix this.
The ~120 Hz hole is typical of TWQT's. It is the first overtone. More stuffing will help.
The ~180 Hz hole is most likely floor bounce. There is really nothing you can do about this one.
You have generated one of the best examples of baffle step that I have seen. Note that the trend line is ~ -2.5 dB to ~800Hz then it jumps to ~ +2 dB. Something around a 1 mH inductor || 6 ohm resistor is flatten it out. But then, this has aready been addressed earlier in the thread.
Bob
BobBrines : thanks very much for your analysis !
I've realised these speakers are underftuffed because the peak is sharper than in the MathCad simulation. Also, the CSD isn't clean so more stuffing on the walls behind the driver should partially correct for that.
For the 180Hz tone, if it is a floor bounce problem, then it will be corrected very soon, I have designed some stands and I will install them as soon as possible.
Concerning baffle step, well, yes it may be a very good example for noobs
Right now I'm correcting for that just with my computer's equalizer, but if I wanted to sell these speakers, or install them somewhere else, I'd design a passive BSC circuit and post it on my website.
One curious thing is that sweeps give a smoother result than gated sine wave, surely because the bigger number of points. But then I don't have the distorsion measurements.
It's very hard to measure speakers in my very small student flat you know
I've realised these speakers are underftuffed because the peak is sharper than in the MathCad simulation. Also, the CSD isn't clean so more stuffing on the walls behind the driver should partially correct for that.
For the 180Hz tone, if it is a floor bounce problem, then it will be corrected very soon, I have designed some stands and I will install them as soon as possible.
Concerning baffle step, well, yes it may be a very good example for noobs
Right now I'm correcting for that just with my computer's equalizer, but if I wanted to sell these speakers, or install them somewhere else, I'd design a passive BSC circuit and post it on my website.
One curious thing is that sweeps give a smoother result than gated sine wave, surely because the bigger number of points. But then I don't have the distorsion measurements.
It's very hard to measure speakers in my very small student flat you know
Scottmoose said:Count yourself lucky my friend. At least you can do some. Almost all my gear, including all my measurement kit, had to be sold when I started my doctorate.
Oh yes, I don't complain about having a flat for my studies, as well as having pocket money to build speakers (which is a costly hobby !). I know friends who couldn't afford that (and many others that are not interested in this stuff
)What doctorate did you start ? Have you finished it ?
Scottmoose said:About half-way through at the moment. It's in naval history of all things -armoured & protected cruisers around the turn of the 19th - 20th century to be precise. Well, somebody has to!
Ok so not directly related to speaker building ! What brought you in this hobby ? You seem to have quite much experience on the forum !
Same as a lot I suspect -a total dissatisfaction with commercial speakers generally. Most are passable, some are bad, very few are actually up to much. Usually variations on the same old theme too.
I also like the blend of art and science that exists in sonic reproduction, the creative process entailed, and the ability to match a system to my own sonic desires. FR drivers are particularly flexible for this -though I'm not blind to their limitations. If I had the money and space, I'd probably run something like my own take on the Altec VOTT.
What about you?
I also like the blend of art and science that exists in sonic reproduction, the creative process entailed, and the ability to match a system to my own sonic desires. FR drivers are particularly flexible for this -though I'm not blind to their limitations. If I had the money and space, I'd probably run something like my own take on the Altec VOTT.
What about you?
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