Speakers (Altec 604?) inside built-in cabinets?

Thanks for the additional info. I was searching online for some examples of what you're describing with the felt and only found one at this link and shown in the image below. That's fairly easy to implement on a small bookshelf speaker like that, but will be much harder on my large grilles.

I'm sure I could figure something out. Foam would probably more practical for my application, but there may also be a fairly large gap between the baffles and the grilles that would be harder to fill. I think the minimum gap I could achieve would be 3/4", but I was also thnking about placing the baffles on an angle to create some toe-in. I got this idea from the vintage speakers shown below, but this which would create a much larger gap. Now that I think about it, I would imagine this might also increase the possibility of vibrating grilles, but I'm not sure. So I'll have to keep that in mind.
932cf5_10f3b81b4a20445880ef60af61a891c4~mv2.jpeg


Screen Shot 2024-10-08 at 1.23.41 PM.png
Screen Shot 2024-10-08 at 1.23.50 PM.png
 
So... I've been slowly picking away at this project and I'm pretty happy with it so far. I tried installing the baffles on an angle to create some toe-in, but I found I lost a lot of bass for some reason. So I scrapped that idea, and went back to the original setup with the baffles parallel to the back wall and it sounds better.

Over the last few months I've also restored a Scott LK-72-B integrated amp and it sounds great with the Altecs.

I feel pretty confident that I will be happy with the audio qualities, so I'm moving forward with the cosmetic details like the frames that will hold the grill cloth.

A couple posts back I shared a prototype frame with an arched top and today I made a simpler rectangular one. I'm going to live with them for awhile, but I'm curious if anyone here has a preference?

My feeling now is the arched top adds a little extra style, but it will also be a bit more difficult to construct. So I'm weighing those factors as well.

The frames will be painted the same colour as the cabinets and I will be using Guilford of Maine acoustic cloth as seen below.

I will also be looking at some of the ideas mentioned previously to dampen the frames, but I haven't noticed any problems so far, even with the prototype frame sitting loosely in the cabinet opening.

Cheers,

Andy

IMG_1094.jpeg
IMG_1087.jpeg
IMG_1090.jpeg
 
Last edited:
Thanks for the additional info. I was searching online for some examples of what you're describing with the felt and only found one at this link and shown in the image below. That's fairly easy to implement on a small bookshelf speaker like that, but will be much harder on my large grilles.
Before the bean counters took over, they used pegboard as the grill cloth back plate to create a grill 'sandwich' and as you say, foam could be used to fill the gap.
 
  • Like
Reactions: streetcore
Excellent work!

I remember a very old book written by someone at Altec showing cabinet drawings and photos of actual installations. I particularly remember a photo of Altecs built into a brick wall on either side of a big fireplace. talk about non-resonate cabinets!

Keep us posted as you progess.

Best, Fred
 
Yeah, the man that literally 'wrote the book' on W.E./Lansing/Altec cinema horn designs chose IB for HIFI, so while I've thoroughly enjoined many different horn systems, got to admit that the false wall IBs I did for others using co/tri-ax speakers did provide a more 'HIFI' performance, especially for up to late '50s AM/FM/vinyl mono apps and to this day still prefer well done mono over early stereo even with stereo speakers I grew up with.
 
  • Like
Reactions: GM and EarlK
Before the bean counters took over, they used pegboard as the grill cloth back plate to create a grill 'sandwich' and as you say, foam could be used to fill the gap.
Thanks for the suggestion about the pegboard. I've been thinking of various ways to attached the Guilford of Maine acoustic fabric over such a large area and I'm worried about stretching it evenly to avoid sags, wrinkles, etc. Attaching it to some pegboard first might help avoid some of those problems. So I'll be giving that some more thought when I get to that stage.

After talking to a friend about the rectangular vs arched frames, I decided to go with rectangular. They tie-in better with the lines in the built-ins and, as my friend said, it's a more timeless look. I initially thought I would make a test frame out of mdf and then make the final frames out of oak, but they're going to be painted anyway, so I'm going to stick with the mdf and see how it looks when painted. It's more stable and less likely to warp or have problems from temperature and humidity changes too.

IMG_1108.JPG
IMG_1109.JPG
IMG_1110.JPG