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Old 23rd April 2013, 03:16 PM   #151
IG81 is offline IG81  Canada
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Quote:
Originally Posted by xrk971 View Post
I am looking at the BG20 and it looks rather attractive in WinISD with low reaching bass into the 30 Hz range. I am considering making a AMLTL with it. Does anyone have listening impressions of this driver for its mid and high frequencies? Seems very cost effective for a 92 dB 8 inch class FR driver.
The resulting enclosure may end-up being quite large looking at Qts and Vas. Reflex simulation seems to agree with this as well.

IG
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Old 23rd April 2013, 03:29 PM   #152
xrk971 is online now xrk971  United States
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IG,
There is no doubt this thing will be large looking, but how does it sound? I am now really interested in bipole configurations seeing how successful it was with the W3-881si that Ryan just built. I know, a bipole with BG20 will be a huge speaker...

Here is my initial AMLTL design for a bipole BG20 AMLTL:

163 liter volume tuned for 37 Hz - very smooth bass shelf.
12 in wide x 17 in deep x 48 in tall (not much bigger than a WIBAQ)
qnty 2 x 3.75 in dia x 4.65 in long ports near bottom.

Usual driver located at 1/3 down or 16 inches from top, stuffing top 32 in at up to 1 lb/cu ft.


WinISD says this will have 95 dB efficiency at 1 watt 1 meter. With bipole, no BSC is needed. If this driver can truly hit 17 kHz, that would be enough for me as I can't hear anything higher.

Last edited by xrk971; 23rd April 2013 at 03:31 PM.
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Old 23rd April 2013, 06:44 PM   #153
IG81 is offline IG81  Canada
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Quote:
Originally Posted by xrk971 View Post
IG,
There is no doubt this thing will be large looking, but how does it sound? I am now really interested in bipole configurations seeing how successful it was with the W3-881si that Ryan just built. I know, a bipole with BG20 will be a huge speaker...

Here is my initial AMLTL design for a bipole BG20 AMLTL:

163 liter volume tuned for 37 Hz - very smooth bass shelf.
12 in wide x 17 in deep x 48 in tall (not much bigger than a WIBAQ)
qnty 2 x 3.75 in dia x 4.65 in long ports near bottom.

Usual driver located at 1/3 down or 16 inches from top, stuffing top 32 in at up to 1 lb/cu ft.

WinISD says this will have 95 dB efficiency at 1 watt 1 meter. With bipole, no BSC is needed. If this driver can truly hit 17 kHz, that would be enough for me as I can't hear anything higher.
163L is pretty much the default WinISD reflex box, for a single driver; two of them in the same volume looks OK, not too much of a midbass hump yet, but not ideal for a small room IMO. Should be pretty punchy since the MLTL won't have a midbass through to fill in addition to the hump with two drivers. Better if that's not coincident with a room mode though.

BG20 might be good in the yet-to-be-built Karlsonator: http://img141.imageshack.us/img141/124/karlsonator.png

I have a pair of Peerless 8" nomex-cone drivers that I'm shooting ideas for, scrapped most of them except MLTL so far. I'll see where that takes me.

IG

Last edited by IG81; 23rd April 2013 at 06:49 PM.
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Old 23rd April 2013, 08:05 PM   #154
xrk971 is online now xrk971  United States
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IG,
If I were to make the BG20 bipole MLTL they will go in the big recreation room 20 ft x 30 ft. I am wanting to give this a try with that thick isocyanurate sheathing insulation foam. Should keep it light weight. I can imagine if it were made if 3/4 in ply it would be a bear to move. Do you think 3/4 in thick foam can work if braced sufficiently?
Those peerless drivers you mention sound interesting, what model number is that?

The Karlsonator would be fun to try in thick foam with the BG20.
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Old 23rd April 2013, 09:52 PM   #155
IG81 is offline IG81  Canada
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Quote:
Originally Posted by xrk971 View Post
IG,
If I were to make the BG20 bipole MLTL they will go in the big recreation room 20 ft x 30 ft. I am wanting to give this a try with that thick isocyanurate sheathing insulation foam. Should keep it light weight. I can imagine if it were made if 3/4 in ply it would be a bear to move. Do you think 3/4 in thick foam can work if braced sufficiently?
Those peerless drivers you mention sound interesting, what model number is that?

The Karlsonator would be fun to try in thick foam with the BG20.
3/4 might be decent if braced to show indication of bass performance, but might be lots of work to do so.

The Peerless drivers are the 830869.

IG
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Old 24th April 2013, 02:34 AM   #156
ryani is offline ryani  United States
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X How many glue sticks will that take together? ? ? haha. Can't wait to see it.
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Old 24th April 2013, 02:44 AM   #157
xrk971 is online now xrk971  United States
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Ryan,
That's funny... I never even thought about using hot melt on this Construction adhesive from a big caulk gun was what I am thinking. Hot melt can probably be used to tack pieces together and then seal with the caulk gun. Not sure if I want to buy $110 in drivers I have no experience with. I haven't gotten any feedback from folks whether or not these BG20's have sufficient high frequency quality. Are you continuing to enjoy your bipole MLTL's? What's the best sounding albums on these speakers?
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Old 24th April 2013, 02:26 PM   #158
xrk971 is online now xrk971  United States
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Default Compact Wall-Mount MLTL Design

I am working on my latest design for a compact Vifa TC9FD wall-mount speaker designed using the AMLTL method. One of the requirements was that it be relatively flat. I decided to start with the TABAQ as a design basis and then modify it from there to suit the cabinet size and materials I have on hand. The TABAQ nominal design calls for a 20 square in CSA (4 in x 5 in typ) and a 30.7 in long line length with a 4 in x 0.75 in (2.5 square inch CSA) x 3.75 in long vent, of course with usual driver mounted at 1/3 from closed end and stuffing in first 2/3rds.
I have some wood-grain masonite (chip board) panel on hand that is 11.25 in wide so I made 2 baffles 17 in tall with top-centrally mounted driver so that the speaker can be used for either left or right channel. Being 17 in tall with a single fold, the line length is 34 in instead of 30.7 in. I decided to stick with the 20 sq in CSA and with 3/16 in foam core walls, the TL width is 5.33 in which specifies a 3.75 in depth. Using these dimensions for a 11.13 liter box tuned to 61 Hz, I end up with a circular 2.0 in dia x 4.18 in long vent. I have decided to put the vent downward firing.
The baffle is 1/4 in thick masonite and is the first time I have made a speaker baffle out of something other than foam core. The walls, back, and dividers will still be foam core.
Attached Images
File Type: jpg Folded-Vifa-AMLTL-01.JPG (124.1 KB, 1787 views)

Last edited by xrk971; 24th April 2013 at 02:33 PM.
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Old 26th April 2013, 01:20 PM   #159
ryani is offline ryani  United States
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Well X i think I found a start to a MLTL with a 6.5" Maybe 2 of the 4ohm in a bipole MLTL. This thread has good start. 60 inch line. I'll try and draw a box up tonight and I will let you critique if you graciously would.

I know I know in the long run it will have to turn into a 2way with a bit of tweeter help.

TL for silver flute 6.5"?
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Old 26th April 2013, 02:48 PM   #160
GM is offline GM  United States
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Quote:
Originally Posted by xrk971 View Post
Using these dimensions for a 11.13 liter box tuned to 61 Hz, I end up with a circular 2.0 in dia x 4.18 in long vent. I have decided to put the vent downward firing.
Hmm, in theory, the vent terminus needs to be > 3*r from a parallel surface, so it will be interesting to see what it winds up being tuned at, especially since the cab's construction is somewhat lossy. Then again, tuning is so far below Fs, it may be a moot point.

GM
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