Use the parameters on the Tangband website for preliminary modeling, and measure the T/S parameters before you start making sawdust.
Further down on the page you linked, they name it as a 1071F. I was in contact with tangband earlier, and there was a set of wrong parameters out there, that they fixed on the web page. The spec shet at Tbspeakers should be correct. Just confirm with the supplier if it is a D or F model, since the page mention both.
Johan-Kr
Further down on the page you linked, they name it as a 1071F. I was in contact with tangband earlier, and there was a set of wrong parameters out there, that they fixed on the web page. The spec shet at Tbspeakers should be correct. Just confirm with the supplier if it is a D or F model, since the page mention both.
Johan-Kr
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I want to add on to that that you want to measure the T/S parameters AFTER you broke in the woofer.
Hi, I contacted the webshop owner and he confirmed that both models are identical, one is the old model name.
I did a comparison in Leonardo Audio between these two drivers:
Tangband W8Q-1071F 8x12"
SB Acoustics SB23NACS45-8
With equal output the excursion of the SB Acoustics drover is much higher than the Tangband driver. I guess that's because of the much larger piston area of the Tangband. So I think for a given sound pressure level, distortion will decrease as piston area and motor size is increased? If so, the Tangband would be the better driver as it has a larger piston area and larger motor size?
I did a comparison in Leonardo Audio between these two drivers:
Tangband W8Q-1071F 8x12"
SB Acoustics SB23NACS45-8
With equal output the excursion of the SB Acoustics drover is much higher than the Tangband driver. I guess that's because of the much larger piston area of the Tangband. So I think for a given sound pressure level, distortion will decrease as piston area and motor size is increased? If so, the Tangband would be the better driver as it has a larger piston area and larger motor size?
Correct, when it comes to volume output there's 'no replacement for displacement' [Vd = swept area x stroke] or in this case, driver [Sd x Xmax] for low distortion peak dB/Spl.
GM
Hi,
thanks again for all replies and help. I downloaded the spreadsheet based on Martin King's "Transmission Line Alignment Tables" and filled in the T/S parameters from the manufacturers website:
After that I filled in the calculated values from the spreadsheet into Leonardo Audio simulation software for a 1 element straight line:
Next step is to fold the line.
Regards
thanks again for all replies and help. I downloaded the spreadsheet based on Martin King's "Transmission Line Alignment Tables" and filled in the T/S parameters from the manufacturers website:
An externally hosted image should be here but it was not working when we last tested it.
After that I filled in the calculated values from the spreadsheet into Leonardo Audio simulation software for a 1 element straight line:
An externally hosted image should be here but it was not working when we last tested it.
Next step is to fold the line.
Regards
When you're folding the line, you'll need to use a bit of trial and error and simulate again. Remember to have enough space inside for the woofer - the Tangband is pretty massive, compared to, for instance, a Kef B139.
You'll end up with somehing like the structure I posted.
A trick when simulating in several sections, is to have heavier damping in the closed end, and lighter towards the end.
Johan-Kr
You'll end up with somehing like the structure I posted.
A trick when simulating in several sections, is to have heavier damping in the closed end, and lighter towards the end.
Johan-Kr
Greets!
You're welcome!
Excellent reason!
Obviously I didn't notice your join date, just 'assumed' that if interested/knowledgeable about TLs, TQWTs........ my bad .
Regardless, if one breaks down the range of usable T/S specs for vented alignments into three segments, then low[er] Qts drivers that require an acoustically small cab [Vb] with a long vent could be morphed into an inverse tapered TQWT to get a sufficiently long, large vent area [Av]; then conversely, an expanding, vented [mass loaded] ML-TQWT [I like to define them as ML-horns] will work well for high[er] Qts drivers that require a large [Vb] with a short, large [Av], leaving the simple constant [straight] tapered ML-TL to cover the ~0.31-0.52 Qts range where a ~0.4 Qts yields a Vb = Vas, Fb = Fs alignment.
Of course any of these pipe alignments can be used over the entire range of Qts if the needs of the app [or personal preference] dictates it, so strictly a guideline.
GM
You're welcome!
Excellent reason!
Obviously I didn't notice your join date, just 'assumed' that if interested/knowledgeable about TLs, TQWTs........ my bad .Regardless, if one breaks down the range of usable T/S specs for vented alignments into three segments, then low[er] Qts drivers that require an acoustically small cab [Vb] with a long vent could be morphed into an inverse tapered TQWT to get a sufficiently long, large vent area [Av]; then conversely, an expanding, vented [mass loaded] ML-TQWT [I like to define them as ML-horns] will work well for high[er] Qts drivers that require a large [Vb] with a short, large [Av], leaving the simple constant [straight] tapered ML-TL to cover the ~0.31-0.52 Qts range where a ~0.4 Qts yields a Vb = Vas, Fb = Fs alignment.
Of course any of these pipe alignments can be used over the entire range of Qts if the needs of the app [or personal preference] dictates it, so strictly a guideline.
GM
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Hi,
I just tried to model a few configurations, if I'm correct: ML, ML-TQWT and TQWT. I used the spreadsheet for all three simulations to get line length and SO and S1.
The tapered lines have much smaller line length so I would think ML-TQWT or TQWT will be the best option. I played with the stuffing and used 4 kg/m^3 for all simulations, but I can't see much difference between ML-TQWT and TQWT when it comes to stuffing - the ML-TQWT shows less ripple in frequency response. Am I doing something wrong, or is the software not capable of doing stuffing simulations that well?
ML-TQWT:
(S1/SO: 0.1, actual length: 1,911)
TQWT:
(S1/SO: 0.1, actual length: 1,911)
MLTL:
(S1/SO: 1, actual length: 3,094)
I just tried to model a few configurations, if I'm correct: ML, ML-TQWT and TQWT. I used the spreadsheet for all three simulations to get line length and SO and S1.
The tapered lines have much smaller line length so I would think ML-TQWT or TQWT will be the best option. I played with the stuffing and used 4 kg/m^3 for all simulations, but I can't see much difference between ML-TQWT and TQWT when it comes to stuffing - the ML-TQWT shows less ripple in frequency response. Am I doing something wrong, or is the software not capable of doing stuffing simulations that well?
ML-TQWT:
(S1/SO: 0.1, actual length: 1,911)
An externally hosted image should be here but it was not working when we last tested it.
TQWT:
(S1/SO: 0.1, actual length: 1,911)
An externally hosted image should be here but it was not working when we last tested it.
MLTL:
(S1/SO: 1, actual length: 3,094)
An externally hosted image should be here but it was not working when we last tested it.
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Meanwhile I ordered a pair of Tangband drivers. The only thing I'm not sure about is if my simulations look all right and if / why a mass loaded (tapered) line would be preferable to a non mass loaded (tapered) line. I can't see a significant effect on needed stuffing and frequency response?
If stuffing doesn't help with frequency response, it WILL help with things like Chuffing and unloading.
Note that the MLTL would be much shorter, 'fatter', only needing to be long enough to generate sufficient 1/4 WL TL pipe action to damp the vent some; thus only requiring minimal damping, typically lining just the top, one side and back with 1" fiberglass insulation or similar.
For the popular finished ~38" driver/floor height [double panel thickness bottom] it would be L = ~142.4 cm tall i.d. [inside dimension] using 3/4" thick panels [preferably no void plywood] and at least 100 L net based on a 70.3 L Vas/0.33 Qts [+ driver, vent, bracing] with the driver down ~49.7 cm. The vent would be down around 113.9 cm and 81 cm^2 with whatever length gives you the tuning you want once damped.
For other driver, vent positions, they ideally need to be at an odd harmonic [3rds, 5ths], though due to the impact of the 1/2 WL vent mass loading, these shift a bit, so if not end loaded, then L*0.21, 0.349, 0.42 is popular for drivers and 0.84, 0.9 for vents.
GM
For the popular finished ~38" driver/floor height [double panel thickness bottom] it would be L = ~142.4 cm tall i.d. [inside dimension] using 3/4" thick panels [preferably no void plywood] and at least 100 L net based on a 70.3 L Vas/0.33 Qts [+ driver, vent, bracing] with the driver down ~49.7 cm. The vent would be down around 113.9 cm and 81 cm^2 with whatever length gives you the tuning you want once damped.
For other driver, vent positions, they ideally need to be at an odd harmonic [3rds, 5ths], though due to the impact of the 1/2 WL vent mass loading, these shift a bit, so if not end loaded, then L*0.21, 0.349, 0.42 is popular for drivers and 0.84, 0.9 for vents.
GM
Hi,
it has been a while but I got a pair of new Tangband drivers and I just finished my first drawing. I'm wondering if I've positioned the center line (blue line) that is used to calculate segment length (and total length) correctly? I've drawn green lines and used the center of these green lines to position the blue lines, in order to get the blue center line always running in the center of the channel.
it has been a while but I got a pair of new Tangband drivers and I just finished my first drawing. I'm wondering if I've positioned the center line (blue line) that is used to calculate segment length (and total length) correctly? I've drawn green lines and used the center of these green lines to position the blue lines, in order to get the blue center line always running in the center of the channel.
An externally hosted image should be here but it was not working when we last tested it.
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The blue lines are, as far as I know, indeed used to calculate both the length of your entire path, and the length of your segments like S1/2/3.
Hi Johan,
as you can see in my previous post I tried to position / draw a center line in order to get the length of each segment into the simulation software. But I'm a bit confused after drawing these lines, maybe you can help?
When looking at your drawing, the first bend in the line (top left) consists of three segments, whereas the second bend in the line (bottom right) consists of four segments. Is there a reason for having different number of segments for each bend - or doesn't it really matter? (the more bends the closer to the total line length?)
Another thing that stays unclear to me is should I draw the lines exactly in the middle between the cabinet walls, or parallel to them? If I'm correct the first and second vertical blue lines, starting from the left side, run parallel to the (black filled) walls right to them, but the third vertical blue line on the right seems to run in between the walls (in the middle), not parallel to one of them.
I'm not sure if my concerns are a problem at all, i.e. would it have a small or big impact on the final result.
It doesn't really matter - it's a little inconsistency on my part, but the more segments you have, you get a little more accurate. However, being super accurate in the lengths is not really productive. The drawing of the path is a bit unprecise anyways, so you're just making more work for yourself with too many segments.
In a large area, doing too few segments will make the part a bit shorter than it really is. I try to keep to 45 degree segments or less, but in the drawing, the driver blocks some of the flow around the first bend, so it won't be too accurate anyways.
Being super-accurate here mostly makes yourself more work here. You're trying to approximate the path around the line. As you can see in my drawing, I try to get close to what a rounded curve around the bend would be, instead of getting 90 degree angles on the path. Likewise - not going through a 45 degree bend with a straight line.
Johan-Kr
Last week I finished the enclosure drawing and today I measured a few T/S parameters of the (not-broken-in) Tangband W8Q-1071F drivers:
It seems the measured numbers are not that far off from the specs on the manufacturer website.
I will let them play a sine wave at resonant frequency tonight and do antother measurement before starting with building the loudspeaker case.
An externally hosted image should be here but it was not working when we last tested it.
It seems the measured numbers are not that far off from the specs on the manufacturer website.
I will let them play a sine wave at resonant frequency tonight and do antother measurement before starting with building the loudspeaker case.
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