Yet again, another 604 MLTL...

I finally got my MLTL boxes up and running yesterday. They arent quite as heavy as I had imagined they would be, but they are not lightweight either! They are 25mm BB ply, with double thick tops and bottoms. Walnut veneered. I had this wood sitting in my shed for the last 3 years, and I had a wood shop teacher at a local school help me do these.

I had to rewire the xo's so that I had some more length on the leads to the driver from the xo, since it is external to the box. I also soldered in a cheap variable wiper resistor in to tune the shelving for the woofer. I am sure that kills some of the sound quality, but it is temporary.

As a couple of you know, I had to take a punt on the stuffing since you cant get OC 703 panels here in NZ, and the equivalent Quiteline panels are $200 each. So, I got a twin winter duvet inner and a couple of pillows from the Warehouse, and used them.

In general, the sound quality is very nice. It certainly is different (better) having the drivers at ear level vs shin level as they were in the OBs. The upper mids are definitely better - more detailed/articulated. Snare brushes are coming through with a lot more clarity and expression now. It is just that the bass is a bit recessed - thin and dry - perversely the OBs had deeper bass!

Tonight I will toss a thick piece of ply under each speaker to see if that tightens things up a bit from the port firing directly into the heavy carpet. I knew they might be over damped like this - but it easier to open them up and cut down the stuffing than try and patch more in. In a couple of days I will take out the pillows off the top and use a single layer of the duvet, and cut the double hanging layer so that it ends just below the driver height. That should reduce the dampening material by > ~1/2. And then we can see how it goes...

Very, very, nice!!! Thank's for posting these photo's. Please keep us posted on the results of your experiments!!
Cheers
Frank M

Yep I think when you get the pillows out you'll sound better. Have fun. :)

If I'm not mistaken, you have not built an MLTL, but a bass reflex. MTML aka labrynth, has a waveguide of sorts that lets the LF develope inside the cabinet much differently than a bass reflex. Do a web search for details, as I'm having trouble copying the link to this page. Open the one titled keith snook Wireless World

Nice looking project.

I believe it is just for the sake of the picture and that you've already accounted for it of course:

-ensure the duvet is not covering the port opening
-is the duvet hanging like a curtain inside, right up against the driver? It should be ~affixed to 3 of 6 sides, not including the baffle and port sides.