I understand your thinking but I'm not so sure I agree. My reasoning is that since the frequencies of the two telephone spikes are pretty similar, they will both be damped by the same stuffing. But damping dis-similar frequencies requires stuffing in more places and hence more stuffing.
Eric
Bjørn,
Personally I think 28.7 cm position looks better.
Actually, I think we have an idea in our minds of what a TL should look like and the higher position is more common and hence "looks right". But luckily I have not been building TL's for long, so the high position is not as deeply ingrained for me!
More seriously, regarding the issue of the 60 Hz peak, cross sectional area, stuffing etc, there are some interesting aspects to discuss:
First, is stuffing the right way to address room gain? I assume that by "room gain" you mean resonances from room dimensions, is that correct? Aren't those better addressed by absorbers in the room instead of in the speakers?
Second, regarding the 60 Hz peak, you write that a smaller cross section will reduce bass output. But isn't that exactly what adding stuffing does? I mean, how do you avoid "boomy base" without reducing the bass output? I submit for the purposes of discussion that (slightly) reducing the cross-section may be just as effective at addressing the boomy bass as adding stuffing would be, without any more negative impact on overall bass output. Is that wrong?
Finally let me add that I know I have limited experience and hence may be missing something entirely. So please don't interpret my questions and comments in any negative way at all! I'm just trying to learn and help others learn.
Eric
Personally I think 28.7 cm position looks better.
Actually, I think we have an idea in our minds of what a TL should look like and the higher position is more common and hence "looks right". But luckily I have not been building TL's for long, so the high position is not as deeply ingrained for me!More seriously, regarding the issue of the 60 Hz peak, cross sectional area, stuffing etc, there are some interesting aspects to discuss:
First, is stuffing the right way to address room gain? I assume that by "room gain" you mean resonances from room dimensions, is that correct? Aren't those better addressed by absorbers in the room instead of in the speakers?
Second, regarding the 60 Hz peak, you write that a smaller cross section will reduce bass output. But isn't that exactly what adding stuffing does? I mean, how do you avoid "boomy base" without reducing the bass output? I submit for the purposes of discussion that (slightly) reducing the cross-section may be just as effective at addressing the boomy bass as adding stuffing would be, without any more negative impact on overall bass output. Is that wrong?
Finally let me add that I know I have limited experience and hence may be missing something entirely. So please don't interpret my questions and comments in any negative way at all! I'm just trying to learn and help others learn.
Eric
Last edited:
Hi Eric
With MJK software you can sim density and distribution of the stuffing.
In a quarter wave there is little air movement at the closed end and high presure. The opposite is the case at the open end. The most efficient location for the stuffing is in the closed end, leaving the last part of the line un-stuffed.
Stuffing in the upper 2/3 is a good starting point.
The peaks shown in the plot is caused by sound coming from the opening out if phase with the sound from the driver. We only want the contribution to the bass. In the upper frequencies the sound at certain frequencies will add to or subtract from driver´s sound.
It is about damping all the sound coming from the opening except the bass. More stuffing = less peaks / dips and less bass. Less stuffing is of course the opposite. What you choose is a design decision.
Regards
Bjørn
With MJK software you can sim density and distribution of the stuffing.
In a quarter wave there is little air movement at the closed end and high presure. The opposite is the case at the open end. The most efficient location for the stuffing is in the closed end, leaving the last part of the line un-stuffed.
Stuffing in the upper 2/3 is a good starting point.
The peaks shown in the plot is caused by sound coming from the opening out if phase with the sound from the driver. We only want the contribution to the bass. In the upper frequencies the sound at certain frequencies will add to or subtract from driver´s sound.
It is about damping all the sound coming from the opening except the bass. More stuffing = less peaks / dips and less bass. Less stuffing is of course the opposite. What you choose is a design decision.
Regards
Bjørn
Hi Eric,
What I mean by room gain is to design a speaker with a gentle roll of in the bass, as room gain will increase the bass. We do not want boomy bass. TABAQ does not go very low, but the bass that is there, is very clean.
Also notice TABAQ is a large cabinet for a 3" driver. I did this to maximize the output from the opening - controlling the bass with rather dense stuffing.
Eric, I like your comments. TL is an interesting area where the discussions and ideas never ends. I wrote this years ago:
Pearls from Martin J King Quarter Wave Design
Regards
Bjørn
What I mean by room gain is to design a speaker with a gentle roll of in the bass, as room gain will increase the bass. We do not want boomy bass. TABAQ does not go very low, but the bass that is there, is very clean.
Also notice TABAQ is a large cabinet for a 3" driver. I did this to maximize the output from the opening - controlling the bass with rather dense stuffing.
Eric, I like your comments. TL is an interesting area where the discussions and ideas never ends. I wrote this years ago:
Pearls from Martin J King Quarter Wave Design
Regards
Bjørn
Bjørn,
I'm glad to see you did not take any offense from my comments. Also, I have seen your "Pearls.." article before and found it very informative. The other source I really found useful was this one from Bob Brines:
Quarter Wave Resonators
Those two articles really helped me.
Eric
Bjørn,
Thanks for sharing your design with the world! The DIY experience is something special for we who participate.
I have been looking at the newish Tang Band W5-2143 and thinking about substituting it in the large Tabaq you simmed back quite a way in this thread.
The Total Q is lower than that of the original W5-1611's, .38 vs .44, and the Fs is a little lower too (5 Hz). If I understand the design correctly, the line is somewhat close enough in length to allow for the lower Fs, and a small reduction in stuffing would probably compensate for the lower Total Q.
Am I on the right track here?
Thanks,
John
Thanks for sharing your design with the world! The DIY experience is something special for we who participate.
I have been looking at the newish Tang Band W5-2143 and thinking about substituting it in the large Tabaq you simmed back quite a way in this thread.
The Total Q is lower than that of the original W5-1611's, .38 vs .44, and the Fs is a little lower too (5 Hz). If I understand the design correctly, the line is somewhat close enough in length to allow for the lower Fs, and a small reduction in stuffing would probably compensate for the lower Total Q.
Am I on the right track here?
Thanks,
John
I have enclosed sims for the short version as suggested by robskillz.
The result will be very close to the original TABAQ. Build it and share the experience
Have fun!
Bjørn
Now I'm trying to buy one, I am finding that the originally specified W3-315SC is discontinued, but the similar (unshielded) W3-315E is available. Changing the driver in the Leonard Audio sim has hardly any effect, maybe the E version gives slightly higher LF and HF responses. Any reason why this driver would sound worse than the SC? Specs PDF below-
http://www.tb-speaker.com/uploads/files/f652024bec6b38f0c07d087be95ff7ac.pdf
Hi Eric
It is true the higher peaks in the 27.8 position only require light stuffing, but you have to take care of the peak in the low end to avoid boomy bass - you must include room gain - which requires more stuffing to control.
Another thing: The 14,5 speaker will look nicer
Hi Bjørn,
It's been a few days since this part of the conversation, but I'm still trying to understand your explanation above about why you prefer the 14.5 mm position (which eliminates the spike near 500 Hz) compared to the 27.8 cm position (which eliminates the spike near 300 Hz).
Do you mean that the 14.5 mm position (by itself) does something to take care of the peak in the low end (60 Hz)? Your sims (and mine too) show exactly the same peak at 60 Hz regardless of the driver position (7.2 or 14.5 or 27.8) as far as I can tell. So I suspect that wasn't your point.
I do understand that you like the look of the 14.5 mm position better
, but I suspect there's more to it than just that and I'm missing it. Can you clarify?Is there something about the sim that's better with the 14.5 mm position than the 27.8 mm position?
Thanks,
Eric
Hi Bjorn,
First I have to say you are supporting this thread beyond believe. Great job. I admire the concept of MLTL and 1/4 wave.
I have done some research on the SoundSommeliers which I try to listen to on youtube or whatever possible media, just to get an impression of them.
Do you know any representable video of them?
Do they house the Tymphany NE85W-04 drivers?
Thanks.
First I have to say you are supporting this thread beyond believe. Great job. I admire the concept of MLTL and 1/4 wave.
I have done some research on the SoundSommeliers which I try to listen to on youtube or whatever possible media, just to get an impression of them.
Do you know any representable video of them?
Do they house the Tymphany NE85W-04 drivers?
Thanks.
Try to find a 3" or 4" driver to put in the TABAQ. You'll probably get better bass than with that 2.5" driver you mentioned. That's the magic of the TABAQ with its balanced extended bass. Plus, that tymphany has a ragged response above 10k which would probably annoy me enough to cross it to a tweeter.
Stuffing material
As I'm starting to build a mini-TABAQ I thought the following info would be useful as the stuffing material for the TABAQ is specified by weight rather than size.
I found a 2009 datasheet for Intertechnik Sonofil here:
https://www.toms-car-hifi.de/media/pdf/products/0294248001257615743.pdf
This gives the specification for a 40mm pack (2 sheets thick?) as 310 grammes per square metre (310 gsm), and sheet size as 350 x 500mm.
I ordered a piece from Blue Planet Acoustic which came as an unpackaged piece approx. 25mm thick, 350 x 1000mm size that weighs 100g. This equates to about 280gsm, so within the +/-10% tolerance on the spec sheet. 100g is enough for one standard TABAQ enclosure
Hope that helps!
As I'm starting to build a mini-TABAQ I thought the following info would be useful as the stuffing material for the TABAQ is specified by weight rather than size.
I found a 2009 datasheet for Intertechnik Sonofil here:
https://www.toms-car-hifi.de/media/pdf/products/0294248001257615743.pdf
This gives the specification for a 40mm pack (2 sheets thick?) as 310 grammes per square metre (310 gsm), and sheet size as 350 x 500mm.
I ordered a piece from Blue Planet Acoustic which came as an unpackaged piece approx. 25mm thick, 350 x 1000mm size that weighs 100g. This equates to about 280gsm, so within the +/-10% tolerance on the spec sheet. 100g is enough for one standard TABAQ enclosure
Hope that helps!
Last edited: