Greets!
Yes, in pre-T/S building days this was a common practice among fairly serious DIYers since we rarely measured any specs other than Fs and plotted crude response plots using a test record or tape and a SLM, just that any air leak will make it a waste of time.
Angle cutting lowers the vent Q, so tuning will be somewhere between the pipe's theoretical longest and shortest acoustic pathlengths. Taken to the extreme, you wind up with a Karlson Coupler tuned pipe, though it doesn't work as well as he predicted, so his later pipe designs were simple angle cuts.
GM
Yes, in pre-T/S building days this was a common practice among fairly serious DIYers since we rarely measured any specs other than Fs and plotted crude response plots using a test record or tape and a SLM, just that any air leak will make it a waste of time.
Angle cutting lowers the vent Q, so tuning will be somewhere between the pipe's theoretical longest and shortest acoustic pathlengths. Taken to the extreme, you wind up with a Karlson Coupler tuned pipe, though it doesn't work as well as he predicted, so his later pipe designs were simple angle cuts.
GM
Greets!
http://www.quarter-wave.com/Models/MathCad_Models.html
Or if you have some faith and willing to build one without a MathCad sim, then you can use his Classic Alignment Tables: http://www.quarter-wave.com/Theory/Alignment_Tables.pdf
GM
http://www.quarter-wave.com/Models/MathCad_Models.html
Or if you have some faith and willing to build one without a MathCad sim, then you can use his Classic Alignment Tables: http://www.quarter-wave.com/Theory/Alignment_Tables.pdf
GM
Well A stronger motor than I realized
Well I got some handitak and did a careful job of measureing the params using the tsparam spreadsheet and using the added mass method of Vas measurement.
Well my earlier measurements underestimated the strength of that big honkin magnet. It looks like it will not only make a good TL but an excellent horn driver as well. Hornresp simulated a very nice 10.5 foot long exponential bass horn with smooth response from about 30Hz to nearly 400Hz giving about 110dB/Watt. TL is rather less efficient but still models about 113dB@25watts which would be maximum excursion given my guess of 3mm Xmax. Still no slouch. The horn would reach maximum excursion with only 7 Watts but sould be putting out about 118dB.
mike
Well I got some handitak and did a careful job of measureing the params using the tsparam spreadsheet and using the added mass method of Vas measurement.
Well my earlier measurements underestimated the strength of that big honkin magnet. It looks like it will not only make a good TL but an excellent horn driver as well. Hornresp simulated a very nice 10.5 foot long exponential bass horn with smooth response from about 30Hz to nearly 400Hz giving about 110dB/Watt. TL is rather less efficient but still models about 113dB@25watts which would be maximum excursion given my guess of 3mm Xmax. Still no slouch. The horn would reach maximum excursion with only 7 Watts but sould be putting out about 118dB.
mike
Attachments
Greets!
With a near 10% midband efficiency, it can theoretically be loaded to as wide a BW as ~6.75 - 630 Hz without too high a CR or ultra low flare rate. Not to mention a fine scoop horn driver. Apparently Jensen's version of the Altec 515 basshorn driver of the day. If so, then it probably has a somewhat higher Xmax, which seems reasonable considering what app it was designed for.
GM
With a near 10% midband efficiency, it can theoretically be loaded to as wide a BW as ~6.75 - 630 Hz without too high a CR or ultra low flare rate. Not to mention a fine scoop horn driver. Apparently Jensen's version of the Altec 515 basshorn driver of the day. If so, then it probably has a somewhat higher Xmax, which seems reasonable considering what app it was designed for.
GM
Hi !
I woud like to design a TQWP or a TQWT, but how I see I can do it right with Mathcad and a worsheet for it.
I have already a mathcad, but how can I downloading a tqwp or a tqwt worksheet ? If i have a worksheet, than I open it with the mathcad, fill the driver parameters that I have, but than what shoud I do to calculating, and drawing the diagrams ? I have a worksheet called sample problems, it is a TL designer, but it do not anything after I click on the Tools - calculate - calculate worksheet .
Someone help me
I woud like to design a TQWP or a TQWT, but how I see I can do it right with Mathcad and a worsheet for it.
I have already a mathcad, but how can I downloading a tqwp or a tqwt worksheet ? If i have a worksheet, than I open it with the mathcad, fill the driver parameters that I have, but than what shoud I do to calculating, and drawing the diagrams ? I have a worksheet called sample problems, it is a TL designer, but it do not anything after I click on the Tools - calculate - calculate worksheet .
Someone help me
About Martin's MathCad:
It is not a designer, it is a tool to predict the result before your start with saw and glue. I use Martin's software with great pleasure.
It might help you to read my "Dummies" on
http://www.t-linespeakers.org/
or my article in July issue of Ax.
Bjorn Johannesen
Wonderful Copemhagen
It is not a designer, it is a tool to predict the result before your start with saw and glue. I use Martin's software with great pleasure.
It might help you to read my "Dummies" on
http://www.t-linespeakers.org/
or my article in July issue of Ax.
Bjorn Johannesen
Wonderful Copemhagen
Greets!
http://www.diyaudio.com/forums/showthread.php?postid=950695#post950695
If you still have questions, please start a new thread.
If you want to make a computer drawing, use MathCad's SmartSketch or similar. If you want to visualize it in 3D, do a forum search for SKETCHUP.
GM
http://www.diyaudio.com/forums/showthread.php?postid=950695#post950695
If you still have questions, please start a new thread.
If you want to make a computer drawing, use MathCad's SmartSketch or similar. If you want to visualize it in 3D, do a forum search for SKETCHUP.
GM
The worksheets are available on www.quarter-wave.com
The Sections worksheet can be used for any enclosure.
Other worksheets are made for different types of TL for ease of entering the input.
Martin explains this very weel in his documentation.
Hi from Bjorn
The Sections worksheet can be used for any enclosure.
Other worksheets are made for different types of TL for ease of entering the input.
Martin explains this very weel in his documentation.
Hi from Bjorn
Hi !
Sorry But on the website www.quarter-wave.com I found only one worksheet called sample problem.mcd .... Can u give me a link about that worksheet ?
I read on the quarter-wave.com there are many available worksheet :
Available Worksheets :
1. Transmission Lines
* Open End TL Sheet (last revised 04/01/06)
* Closed End TL Sheet (last revised 04/01/06)
* Offset Driver TL Sheet (last revised 04/01/06)
* TL Sections Sheet (last revised 04/01/06)
* ML TQWT Sheet (last revised 04/01/06)
2. Closed and Ported Boxes
* Closed Box w/ Offset Driver Sheet (last revised 04/01/06)
* Ported Box w/ Offset Driver Sheet (last revised 04/01/06)
3. Double Bass Reflex
* Double Bass Reflex Sheet (last revised 04/01/06)
4. Back Loaded Horn
* Back Loaded Horn Contours Sheet (last revised 05/19/06)
* Back Loaded Horn Sections Sheet (last revised 05/19/06)
5. Open Baffle
* Full or Extended Range Driver w/ Woofer (last revised 05/09/06)
* Full or Extended Range Driver w/ Dual Woofers (last revised 05/09/06)
6. Stand Mounted Enclosures
* Closed Box w/ Offset Driver Sheet (last revised 05/22/06)
* Ported Box w/ Offset Driver Sheet (last revised 05/22/06)
* Offset Driver TL Sheet (last revised 06/06/06)
My Questions is from where can I get these ?
Thank You !
Sorry But on the website www.quarter-wave.com I found only one worksheet called sample problem.mcd .... Can u give me a link about that worksheet ?
I read on the quarter-wave.com there are many available worksheet :
Available Worksheets :
1. Transmission Lines
* Open End TL Sheet (last revised 04/01/06)
* Closed End TL Sheet (last revised 04/01/06)
* Offset Driver TL Sheet (last revised 04/01/06)
* TL Sections Sheet (last revised 04/01/06)
* ML TQWT Sheet (last revised 04/01/06)
2. Closed and Ported Boxes
* Closed Box w/ Offset Driver Sheet (last revised 04/01/06)
* Ported Box w/ Offset Driver Sheet (last revised 04/01/06)
3. Double Bass Reflex
* Double Bass Reflex Sheet (last revised 04/01/06)
4. Back Loaded Horn
* Back Loaded Horn Contours Sheet (last revised 05/19/06)
* Back Loaded Horn Sections Sheet (last revised 05/19/06)
5. Open Baffle
* Full or Extended Range Driver w/ Woofer (last revised 05/09/06)
* Full or Extended Range Driver w/ Dual Woofers (last revised 05/09/06)
6. Stand Mounted Enclosures
* Closed Box w/ Offset Driver Sheet (last revised 05/22/06)
* Ported Box w/ Offset Driver Sheet (last revised 05/22/06)
* Offset Driver TL Sheet (last revised 06/06/06)
My Questions is from where can I get these ?
Thank You !
All you have to do is read the entire MathCad Models page on the website. I believe everything you need to do is described in detail.
The sample worksheet is set up to run a single problem and cannot be editted. If you scroll to the bottom and all of the graphs appear then you know the other worksheets will run on your computer and about how long they take to calculate and show the results.
The sample worksheet is set up to run a single problem and cannot be editted. If you scroll to the bottom and all of the graphs appear then you know the other worksheets will run on your computer and about how long they take to calculate and show the results.
You cannot model two distinct drivers at different locations in the TL enclosure ...... yet.
You can model an equivalent driver at the average position of two identical drivers. There is a write up showing this process and the expected results under the General Speaker Related Articles page on my site.
You can model an equivalent driver at the average position of two identical drivers. There is a write up showing this process and the expected results under the General Speaker Related Articles page on my site.
Thank You ! Than I think 1 driver will be enough for me
I purchased the worksheet by one of my friends ( because he has paypal )so now i have all of them. My qestions is : How can I design a tqwt like the Monacor Mindstorm? :
With the ML TQWT worksheet can desing other box, if i think rihgt... ( like Fostex FE-164 in a ML TQWT in the quarter-wave.com
I purchased the worksheet by one of my friends ( because he has paypal )so now i have all of them. My qestions is : How can I design a tqwt like the Monacor Mindstorm? :
An externally hosted image should be here but it was not working when we last tested it.
With the ML TQWT worksheet can desing other box, if i think rihgt... ( like Fostex FE-164 in a ML TQWT in the quarter-wave.com
Yes, the ML TQWT worksheet is the one to use for the enclosure shown in the picture. Part 1 of the worksheet will treat the line as if it were straight, a good approximation at low frequencies. Part 2 of the worksheet needs the external enclosure dimensions, the picture in the worksheet should look like the picture in the above post. The driver and the port should be in the correct positions.
Or How can i design a TQWT something like this :
Thank You !
An externally hosted image should be here but it was not working when we last tested it.
Thank You !
Well I have started cutting but I haven't as much scrap around as I thought so will have to get a couple of sheets before I can finish. In the meantime I was playing with some models and for fun I tried tuning the pipe well below what one would normally do. And lo and behold the response looks a lot like an EBS ported box with a gradual slope down to the tuning frequency and then sharp cutoff below that. Some of these tuning were more than an 8va below the driver's Fs.
So this raises the obvious question. Why couldn't such a tuning be used to compensate for room gain and extend low frequency output (at the expense of max SPL)? For example my Wurlitzer speaker (Fs=45) showed output over 110dB all the way down to 16Hz or so before exceeding estimated Xmax of 6mm. This was down about 10dB from the 50Hz level but it seems possible that room gain might give that back.
Might be worth some experimenting after I get the first box built.
mike
So this raises the obvious question. Why couldn't such a tuning be used to compensate for room gain and extend low frequency output (at the expense of max SPL)? For example my Wurlitzer speaker (Fs=45) showed output over 110dB all the way down to 16Hz or so before exceeding estimated Xmax of 6mm. This was down about 10dB from the 50Hz level but it seems possible that room gain might give that back.
Might be worth some experimenting after I get the first box built.
mike
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