Low-Cost PMC-inspired TL Monitor with DC130A and DC28F

Hello X,

That is some strategic damping placement in the rear most section.
Is that derived from Akabak or measurement and is the length of damping along the line that long because of the taper ratio used?

I built 3 boxes, one is a "test and tune".

Getting there slowly.

I have attached 2 pics of my progress.
18mm Ply.
Crossover will be external.
Rear terminus.
Line length is 47.50 inches with damping along first 33 inches
PXL_20230319_194751716.jpg
PXL_20230319_194943160.jpg
.
The Blue foam is from Amazon, nothing special, vendor who could deliver to my timetable had Red or Blue, I prefer Blue.
Melamine foam in position as per sim by WAE in post #270
Acousta-Stuf to be inserted in beginning of line when I get to that stage.

Thanks again for all your contributions to DIYAUDIO.
 
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Founder of XSA-Labs
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So, is position c.) the magical spot?? and what is the science behind that. Of-course this is just the modeling software, but that's what we have until we build and measure.
I try to place driver anywhere from 1/5th to 1/3rd distance from closed end. Those are the best according to simulation for smooth response with least reflection from exit terminus. There are cases where 1/2 works too.

Ideally it is 1/3rd.
 
Greetings X,

Both boxes sealed. Those are the pics in the post above.
One crosssover completed and working on the other. I tested both boxes on Saturday with the one crossover and so far so good.
I used a Nuforce DDA 120 and CD into the converter of the DDA 120 (convenient). It makes sound and sounds okay but the Nuforce is not exactly particularly good sounding in my opinion so no "review" yet.
I will say the bass is certainly TL like and not like a reflex box.
You may notice the 0.1mH inductor is not the recommended one but it was what P.E. had available.
Also note the repaired 12.5R resistor which I dropped but luckily the conductor was not broken. Cyanoacrylate glue to the rescue.
Enclosures were about 5 feet from the front wall and about the same from the side walls in a ~700 ft3 room.
Bass output was quite strong (in mono!) even with the Nuforce which I have found to have underwhelming bass so the enclosure works well.
This was just a test to see if the enclosures worked (no leaks) and verify the crossover.
Hopefully will get so more testing done along with the other crossover this weekend.

I would tell you they have output at 20Hz but I still cannot believe it.
I put a 20Hz tone through them while testing for the cutoff and the woofer was dancing away and I don't mean straining to hear it either. Yes its going to be heavily distorted but I have few drivers even significantly larger in size that have any output at all at even 35Hz.
The bad...... These need a lot of power, I would say 50W at a minimum required.

Watch this space
 
Founder of XSA-Labs
Joined 2012
Paid Member
Nice work Andrewbee! I see now your fold went out the back for the vent.

I would not have expected anything much at 20Hz. But glad you got some nice bass. They are indeed only about 82.5dB sensitive so 35W to 50W amp is needed.

You can play with the stuffing to get the quality of the bass to suit you. More will be tighter and more cohesive sounding but less in amplitude and not as deep in frequency.

My pre-production TL’s should be arriving by DHL in a few days. I’m looking forward to hearing them.
 
Hello X,

That is some strategic damping placement in the rear most section.
Is that derived from Akabak or measurement and is the length of damping along the line that long because of the taper ratio used?

I built 3 boxes, one is a "test and tune".

Getting there slowly.

I have attached 2 pics of my progress.
18mm Ply.
Crossover will be external.
Rear terminus.
Line length is 47.50 inches with damping along first 33 inches View attachment 1155540 View attachment 1155541 .
The Blue foam is from Amazon, nothing special, vendor who could deliver to my timetable had Red or Blue, I prefer Blue.
Melamine foam in position as per sim by WAE in post #270
Acousta-Stuf to be inserted in beginning of line when I get to that stage.

Thanks again for all your contributions to DIYAUDIO.
Nice build!
Can you please update the thickness of the blue form?
 
With the help and support from Mr. XR971, I completed my First TL speaker.
Listening to TL first time in my life...
Thanks, @xrk971, for this lovely design and for answering all queries during the build.
Thanks to @jmascreen and other members for the reference photos.
I have used locally available 5.25" driver specs similar to DC130. This will be two-way active.

Nice bass; I am trying to find the optimal level of stuffing; the cabinet is not closed yet.
 

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