MLTL design review request - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 16th November 2006, 12:36 AM   #1
bzdang is offline bzdang  Canada
diyAudio Member
 
bzdang's Avatar
 
Join Date: Apr 2004
Location: Pickering, Ontario
Default MLTL design review request

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.
Attached Images
File Type: jpg mltl1.jpg (20.1 KB, 433 views)
__________________
Benford's law of controversy - Passion is inversely proportional to the amount of real information available.
  Reply With Quote
Old 16th November 2006, 12:40 AM   #2
bzdang is offline bzdang  Canada
diyAudio Member
 
bzdang's Avatar
 
Join Date: Apr 2004
Location: Pickering, Ontario
A cad screenshot
Attached Images
File Type: jpg screenshot4.jpg (19.0 KB, 491 views)
__________________
Benford's law of controversy - Passion is inversely proportional to the amount of real information available.
  Reply With Quote
Old 16th November 2006, 01:12 AM   #3
diyAudio Member
 
Join Date: May 2004
Location: San Francisco
Send a message via AIM to joe carrow
Quick comment- from what I've read and what I understand of it, the top end of this enclosure will experience the highest pressures. You would probably be well served by enclosing that horn in a sub-enclosure, in order to prevent flexing due to bass.
  Reply With Quote
Old 16th November 2006, 05:05 PM   #4
bzdang is offline bzdang  Canada
diyAudio Member
 
bzdang's Avatar
 
Join Date: Apr 2004
Location: Pickering, Ontario
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?
Attached Images
File Type: jpg screenshot7.jpg (22.5 KB, 359 views)
__________________
Benford's law of controversy - Passion is inversely proportional to the amount of real information available.
  Reply With Quote
Old 24th March 2008, 08:04 PM   #5
diyAudio Member
 
Kim Bay Smidt's Avatar
 
Join Date: Nov 2004
Location: Aarhus, Denmark
Default 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.
Attached Images
File Type: png w20rc38-08 mltl.png (7.2 KB, 272 views)
__________________
...there's is a difference between knowing the path and walking the path...
  Reply With Quote
Old 24th March 2008, 10:42 PM   #6
ttan98 is offline ttan98  Australia
diyAudio Member
 
Join Date: Apr 2006
Location: Melb
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.
  Reply With Quote
Old 25th March 2008, 04:56 AM   #7
holdent is offline holdent  Canada
diyAudio Member
 
Join Date: Nov 2005
Location: Ontario
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.
  Reply With Quote
Old 25th March 2008, 05:25 AM   #8
holdent is offline holdent  Canada
diyAudio Member
 
Join Date: Nov 2005
Location: Ontario
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!
  Reply With Quote
Old 25th March 2008, 04:46 PM   #9
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Quote:
Ö.Unless you have a very large room and/or like your music really loud you'll probably never run more than 1 watt or 2Ö.
Agree, This driver isnít suitable for ported designs unless the volume used is lower than about 2 cu ft and the driver amp in use is equipped with a HP filter protecting the lower end of the pass band.

See the pictures 1(2)-2(2)

b

1(2)
Attached Images
File Type: gif tad tl-1101h-mltl.gif (37.7 KB, 178 views)
  Reply With Quote
Old 25th March 2008, 04:49 PM   #10
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
2(2)
Attached Images
File Type: gif tad tl-1101h-closed.gif (50.4 KB, 104 views)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wilson Watt Puppy Clone Design - Design Review Please soundengine355 Multi-Way 8 15th August 2008 03:07 PM
TL or MLTL design for PHY-HP? JrM Full Range 4 31st May 2006 10:33 PM
JX92S MLTL Alignment Sanity Check Request rdf Full Range 9 29th May 2006 02:44 AM
Mltl Design With Scanspeak kkchunghk Multi-Way 3 23rd January 2006 04:50 PM


New To Site? Need Help?

All times are GMT. The time now is 04:39 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2