What i´ve got is:
Fs 19Hz, Qts 0,4 Qes 0,44 Vas 270l Re 5 Xmax 22mm P 160W
( i doubt the Xmax value but its what RCF says)
Actually somewhere around 250-300 l TL could be made to look almost as small as present setup.
Thank´s for answer, that site of Yours is nice, i´m feeding paper into the printer..
Fs 19Hz, Qts 0,4 Qes 0,44 Vas 270l Re 5 Xmax 22mm P 160W
( i doubt the Xmax value but its what RCF says)
My wife since 20 Years has an impressive speaker acceptance factor.
Actually somewhere around 250-300 l TL could be made to look almost as small as present setup.
Thank´s for answer, that site of Yours is nice, i´m feeding paper into the printer..
ingvar ahlberg said:
I wonder why they suggest to stuff it that way....
ingvar ahlberg said:
I actually tried another weird thing, I wired it out of phase and the resonance peak went down to about 50 Hz, but the bass response, of course, didn't get better.
I think I'll try a "lighter" stuffing and will let you know how things work out.
Cheers
Andrea
planet10 said:
I am afraid Vifa's specs are a bit "optimistic", the Fs I measured are 6-10Hz more than specs
I feel a little lost with inches and feet, so...
70.6 " = 1,8 m OK
23.7 " = 60 cm ? more like 30-35 cm, drivers are quite close
180 in^2 = 1161 cm^2 ? much smaller, say about 400 cm^2
60 in^2 = 387 cm^2 ---> 135 cm^2
In your simulations the cabinet should be huge...
A link?
Cheers
Andrea
Andypairo said:
i'm ambidextrous, Canada switcjing to metric when i was in junior high school
This is the driver offset -- ie the distance from the closed end of the line of the exact centre of the 2 drivers (in an MTM the middle of the tweeter)
I was trying to illustrate why i thot you box was smallish for bottom end ... Using your measured Fs...
length = 145 cm
driver offset = 48.8 cm
closed end area = 0.148 m^2
open end area = 0.049 m^2
box vol ~ 0.47 m^3
You could see what happens by removing the top driver and plugging the hole left...
dave
If you look at the response plots of the Thor I doubt they will inspire you!
This looks like an F3 of ~100 Hz
This looks like an F3 of ~100 Hz
I have had a few email discussions with the Loudspeaker kit and their TL6 isn't based on the Thor kit. The TL6 is based on the Augsburger model previous to Martin King's work.
I stuffed the front of the box relatively heavily (yes, what the heck does that mean) ... and also tried reducing the stuffing and not using any at all. What I noticed using Martins simulations is that stuffing makes the response smoother more than anything.
I tend to play my speakers with the bass tone control up, which doesn't worry me as I tend to like a lot more bass than most, so I expect to want to do that on any speakers. Although when I get my subs properly setup I'd really like to kill the bass boost, as most amps (this one being no exception) place the boost too high and it tends to go into the lower midrange, so it gets a little muddy when you decide to crank the music (or even a film.)
I suspect that a larger enclosure would improve the bass as others have previously noted. If you look at raymondaudio.com you will find that he used only one woofer for this reason.
I have learnt a lot since I have done mine, when I started I knew very little. I'm not sure what I would have done if I knew what I know now ...
I stuffed the front of the box relatively heavily (yes, what the heck does that mean) ... and also tried reducing the stuffing and not using any at all. What I noticed using Martins simulations is that stuffing makes the response smoother more than anything.
I tend to play my speakers with the bass tone control up, which doesn't worry me as I tend to like a lot more bass than most, so I expect to want to do that on any speakers. Although when I get my subs properly setup I'd really like to kill the bass boost, as most amps (this one being no exception) place the boost too high and it tends to go into the lower midrange, so it gets a little muddy when you decide to crank the music (or even a film.)
I suspect that a larger enclosure would improve the bass as others have previously noted. If you look at raymondaudio.com you will find that he used only one woofer for this reason.
I have learnt a lot since I have done mine, when I started I knew very little. I'm not sure what I would have done if I knew what I know now ...
Andypairo said:
An experiment to see if 1 driver gives better bass (ie doubling the volume of the box by halving the number of drivers). Once the top driver is removed here will be a big hole that needs sealing off.
paulspencer said:
Augspurger's & King's work are contemperaneous... i was talking to Martin about the publishing of his original paper (already passed over for publication in Speaker Builder) when i attended Augspurger's 1st presentation of his work at the NY AES.
dave
paulspencer said:
Hello,
I stuffed the front quite heavily too, and now I'm using no stuffing in the rear chamber. Bass improved but the result is less pleasing than before when the level is higher: don't know if it is only fault of the x-over (voices tend to scream a little when playing loud) or of the less tapered pipe. As soon as I get the active x-over will be able to make a fine tuning.
Dave, in a previous post you mentioned baffle step: by now the speaker doesn't have any compensation for it, because I thought it wouldn't need it... will try that route too.
Cheers
Andrea
Get em fixed?
Did you get them to work properly? I am also doing the same project and now concerned about the sound quality. At this point I can still turn back and go back to bass-reflex and I should theorectically get an F3 of 41Hz. Btw, does anyone have a crossover design using a XT25 with two P17's?
Did you get them to work properly? I am also doing the same project and now concerned about the sound quality. At this point I can still turn back and go back to bass-reflex and I should theorectically get an F3 of 41Hz. Btw, does anyone have a crossover design using a XT25 with two P17's?
Removing the rear stuffing helps, but so far I can't say how these speakers can sound, the tweeter seems to be very nice but the actual x-over is all but good.
I don't worry that much, since I'm going to make good use of the Mox boards as soon as they arrive, but this prevents me from judging them.
Cheers
Andrea
I don't worry that much, since I'm going to make good use of the Mox boards
as soon as they arrive, but this prevents me from judging them.Cheers
Andrea
This reminds me very much of my first TL, back in the 'bad old days' when everything was done with smoke and mirrors. This was a common design and I built something nearly identical with similar drivers.
My first suggestion is to go to Martin King's TL site http://www.quarter-wave.com and read everything. Then download the software, and do some simulations. This will give you a better idea of what is going on. No doubt a much bigger pipe will be called for. Can you post some frequency response measurements?
To make the one that you have built already work, there are some things you can do. I think that as it stands now, there are multiple problems with not only the enclosure alignment, but also the crossover and lack of baffle step compensation (BSC).
Stuffing: my suggestion is to line the back, top and one side of the front chamber with thick carpet felt or eggcrate foam. Foam sometimes will kill the dynamics - especially at soft volumes, but othertimes works very well. Very lightly stuff the area around the bend at the bottom *only* with the polyfill, teasing it out as lightly as you can. Leave the last 1/3 unstuffed.
Port: MJK's softare doesn't predict this, but I have discovered that the exit of a TL isn't like a BR port. The bass does not like to make that last little bend around a corner. It it better to cut the port so that it exits straight out the top without having to bend. At the very least, I would jigsaw the lip around the port out and cut deep flares to try to smooth the bend and exit. Think aerodynamically. Consider patching the current port and cutting the opening in the top.
BSC: this can't be ignored. Make sure that the crossover employs it. One fairly surefire crossover that seems to work well and has built in BSC is the "acoustic-reality" series crossover which you can find on the web.
Lastly, the Q of those drivers is really just a bit too low for good bass extension. I would recommend a warm sounding tube (valve) amplifier with a high output impedance. This can make a *very* good sounding combination with an overdamped TL. If you're using SS amplification, try putting a 3-8 ohm power resistor in series with the inputs to get an idea of the change. The effect can be calculated precisely and predicted in MJK's software, but a quick test will give you a rough idea.
Greg B
My first suggestion is to go to Martin King's TL site http://www.quarter-wave.com and read everything. Then download the software, and do some simulations. This will give you a better idea of what is going on. No doubt a much bigger pipe will be called for. Can you post some frequency response measurements?
To make the one that you have built already work, there are some things you can do. I think that as it stands now, there are multiple problems with not only the enclosure alignment, but also the crossover and lack of baffle step compensation (BSC).
Stuffing: my suggestion is to line the back, top and one side of the front chamber with thick carpet felt or eggcrate foam. Foam sometimes will kill the dynamics - especially at soft volumes, but othertimes works very well. Very lightly stuff the area around the bend at the bottom *only* with the polyfill, teasing it out as lightly as you can. Leave the last 1/3 unstuffed.
Port: MJK's softare doesn't predict this, but I have discovered that the exit of a TL isn't like a BR port. The bass does not like to make that last little bend around a corner. It it better to cut the port so that it exits straight out the top without having to bend. At the very least, I would jigsaw the lip around the port out and cut deep flares to try to smooth the bend and exit. Think aerodynamically. Consider patching the current port and cutting the opening in the top.
BSC: this can't be ignored. Make sure that the crossover employs it. One fairly surefire crossover that seems to work well and has built in BSC is the "acoustic-reality" series crossover which you can find on the web.
Lastly, the Q of those drivers is really just a bit too low for good bass extension. I would recommend a warm sounding tube (valve) amplifier with a high output impedance. This can make a *very* good sounding combination with an overdamped TL. If you're using SS amplification, try putting a 3-8 ohm power resistor in series with the inputs to get an idea of the change. The effect can be calculated precisely and predicted in MJK's software, but a quick test will give you a rough idea.
Greg B
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