I'm working on a straight MLTL design using Martin's simulation software, and I would love to have some more experienced eyes look it over before I make sawdust.
I've been using the ML_TQWT_9_19_06 worksheet. Here is what I have thus far -
Woofer = TAD TL-1101h
Driver T/S parameters (relevant ones for this worksheet)
fd=38Hz
Re=13ohm
Le=2.0mH
Bl=20.5newton/amp
Sd=366cm^2
Vas=92liter
Qes=0.27
Qms=3.86
[Qts is listed in driver spec sheet as 0.25, when I enter the Qms and Qes as above, the MJK worksheet calculates 0.392]
Enclosure Geometry Definition
L=47
zdriver=12.5
zport=45
So=11.5x12
SL=same
Density=0.25
rport=1.5
Lport=2
Power=1
And I liked the look of the simulations with Radd=8ohm (series resistance).
Nice software tool Martin! And group delay is plotted!
Yeah it's a 16ohm driver with a lowish Qts, but I have them and a bit of time to build something. They'll have 1" compression drivers in molded 90x30 horns.
Part of my first design results below.
I've been using the ML_TQWT_9_19_06 worksheet. Here is what I have thus far -
Woofer = TAD TL-1101h
Driver T/S parameters (relevant ones for this worksheet)
fd=38Hz
Re=13ohm
Le=2.0mH
Bl=20.5newton/amp
Sd=366cm^2
Vas=92liter
Qes=0.27
Qms=3.86
[Qts is listed in driver spec sheet as 0.25, when I enter the Qms and Qes as above, the MJK worksheet calculates 0.392]
Enclosure Geometry Definition
L=47
zdriver=12.5
zport=45
So=11.5x12
SL=same
Density=0.25
rport=1.5
Lport=2
Power=1
And I liked the look of the simulations with Radd=8ohm (series resistance).
Nice software tool Martin! And group delay is plotted!
Yeah it's a 16ohm driver with a lowish Qts, but I have them and a bit of time to build something. They'll have 1" compression drivers in molded 90x30 horns.
Part of my first design results below.
Attachments
Thanks for the good advice re enclosing the horn. I may leave the back of the horn sub-enclosure open to provide an accessable place for crossover components. I should plan to add vertical crossbraces at midpoint of the cabinet too.
Got some advice from dogbreath to look at cone excursion at higher power levels, the xmax for that driver is 2.5mm but 'maximum excursion before damage' is +/- 16mm.
I entered 50watts in the worksheet and as shown below, the excursion goes out of bounds below ~33Hz. Do I have this cabinet tuned too low?
Got some advice from dogbreath to look at cone excursion at higher power levels, the xmax for that driver is 2.5mm but 'maximum excursion before damage' is +/- 16mm.
I entered 50watts in the worksheet and as shown below, the excursion goes out of bounds below ~33Hz. Do I have this cabinet tuned too low?
Attachments
Same situation here...
Hi,
Using a newer version of the same ML_TQWT sheet I've designed my first MLTL.
The driver is a Silverflute W20RC38-08 as I've them in house.
L=36"
S0 = 1.5x1.5"
SL = 14x14"
Zdriver = 22.48"
Zport=32" (r=1", L=2")
No stuffing used for simulation.
I'm not fully satisfied 'cause of the sag between 50 and 100 Hz.
What do you think about this MLTL? How can it be improved (not changing the driver)?
Above 150-200 Hz the Planet-10 FE127eN will be used.
Hi,
Using a newer version of the same ML_TQWT sheet I've designed my first MLTL.
The driver is a Silverflute W20RC38-08 as I've them in house.
L=36"
S0 = 1.5x1.5"
SL = 14x14"
Zdriver = 22.48"
Zport=32" (r=1", L=2")
No stuffing used for simulation.
I'm not fully satisfied 'cause of the sag between 50 and 100 Hz.
What do you think about this MLTL? How can it be improved (not changing the driver)?
Above 150-200 Hz the Planet-10 FE127eN will be used.
Attachments
I like your approach, I am building a similar configuration, just one question why you pick this woofer: Woofer = TAD TL-1101h.
By adding an 8 ohm resistor you are losing lots of power, hence lowering the spl. I will not use more than a few ohms.
I have stimulated using low Qts driver around 0.3, the FR may not look that flat, but it sounds very good in actual implementation, a prototype setup.
I am thinking of using this new combo:
woofer:SM110/N
tweeter: compression driver, B&C DE250
should be very dynamic, the box would not be too large, 82litre, and the FR flat to 40 HZ, not as low as yours.
keep us updated. Cheers.
By adding an 8 ohm resistor you are losing lots of power, hence lowering the spl. I will not use more than a few ohms.
I have stimulated using low Qts driver around 0.3, the FR may not look that flat, but it sounds very good in actual implementation, a prototype setup.
I am thinking of using this new combo:
woofer:SM110/N
tweeter: compression driver, B&C DE250
should be very dynamic, the box would not be too large, 82litre, and the FR flat to 40 HZ, not as low as yours.
keep us updated. Cheers.
Kim Bay Smidt:
According to the spec sheet at Madisound (http://www.madisound.com/silverflute.html) the Silver Flute W20RC38-08 has a Qts of 0.233. A low Qts driver like this in an MLTL will always give that characteristic "bump" at the bottom unless you add some series resistance to the driver. Look at the top of Part 1 in MJK's ML TQWT worksheet for Radd and try 1 to 3 ohms to start. Martin has several examples of this on his website for the Lowther DX series and Fostex FE206E projects (see http://www.quarter-wave.com/Projects.html). Note that because you are adding a resistor, the system will end up being a little less sensitive.
Incidently you want the response to slope down rather than aiming for a flat curve. Try aiming for a flat in-room response instead. Thats simulated in Part 2's "Plotted SPL Response for the System" lower down on the worksheet. I learned from experience that you'll get "boomy"-sounding bass otherwise.
According to the spec sheet at Madisound (http://www.madisound.com/silverflute.html) the Silver Flute W20RC38-08 has a Qts of 0.233. A low Qts driver like this in an MLTL will always give that characteristic "bump" at the bottom unless you add some series resistance to the driver. Look at the top of Part 1 in MJK's ML TQWT worksheet for Radd and try 1 to 3 ohms to start. Martin has several examples of this on his website for the Lowther DX series and Fostex FE206E projects (see http://www.quarter-wave.com/Projects.html). Note that because you are adding a resistor, the system will end up being a little less sensitive.
Incidently you want the response to slope down rather than aiming for a flat curve. Try aiming for a flat in-room response instead. Thats simulated in Part 2's "Plotted SPL Response for the System" lower down on the worksheet. I learned from experience that you'll get "boomy"-sounding bass otherwise.
bzdang:
Re your concern about Xmax and power handling - this is a problem with all vented enclosures. Probably what you need to ask yourself is "will the music I listen to at the volume I listen in my room require 50 watts below 33 Hz?" The TAD TL-1101h is a very sensitive woofer at 97dB/W at 1m. Unless you have a very large room and/or like your music really loud you'll probably never run more than 1 watt or 2!
I'm guessing here now but I think that if you are concerned about excursion below 33 Hz you need to tune the cabinet even lower. The great thing about Martin's worksheets is it costs nothing but time to experiment!
Re your concern about Xmax and power handling - this is a problem with all vented enclosures. Probably what you need to ask yourself is "will the music I listen to at the volume I listen in my room require 50 watts below 33 Hz?" The TAD TL-1101h is a very sensitive woofer at 97dB/W at 1m. Unless you have a very large room and/or like your music really loud you'll probably never run more than 1 watt or 2!
I'm guessing here now but I think that if you are concerned about excursion below 33 Hz you need to tune the cabinet even lower. The great thing about Martin's worksheets is it costs nothing but time to experiment!
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