Transparent Baffle

[bzdang]

I have been thinking about how to make a wider front baffle for a slender MLTL to improve the baffle step situation without distressing the wife with a huge-looking box. What about making a transparent faceplate out of acrylic or lexan sheet, or tempered glass, attached to the front of the cabinet, which performs similar function to the wings sometimes seen on TQWT cabinets?
Has anyone done this? Will this help acoustically?
Planet10, what do you think?

The box in the picture is 9 x 9 x 48 inches fyi.

[Paradise_Ice]

It looks good on paper, but i dont know if you could live with it in real life, or if it would be a worth while improvment.

I think a mock baffle from wood is a good idea to see if it makes a sound quality difference?

If you think its worth after that? good for it?

If you have kids in your house then i would advise against glass for obvious reasons.

[MITMechE]

Not exactly the same idea, but I saw some speakers at BestBuy that had a lexan or acrylic baffle and was very nice looking.

Tried to find a link for ya, but I couldn't find one. I can't remember the brand.

[Hybrid fourdoor]

There is someone on here who did this exact thing with glass I think, may have been plexi or Lexan. It was a full range unit.

I'm sure they will post or someone will know who I'm speaking of.

I think this is the thread, but the pictures don't seem to work.

[bzdang]

Hi all, this add-on panel will attach across the front baffle of a complete and working MLTL cabinet. Functionally like adding a sheet of plywood to the front of Bob's Peerless Pipe to make it wider and lower the baffle step frequency. I think that by using clear acrylic sheet, it might improve the performance of the system without looking huge.
Thanks for your suggestion to mock it up, I'll do it with 3/8 inch plywood when I have built the first test box.
Anyone curious enough to add a plywood test panel to an existing speaker and report results back to us?

btw - ask for cast acrylic sheet, not extruded, for your projects, the cast acrylic is much nicer to cut and machine, doesn't froth up and melt onto the tools as much.

[jleaman]

Looks like a cool idea.. what thickness of plexi are you going to use in the end
? pleie flexes so yeah. thin is not to good..

[Zaph]

Originally posted by bzdang
I have been thinking about how to make a wider front baffle for a slender MLTL to improve the baffle step situation without distressing the wife with a huge-looking box. What about making a transparent faceplate out of acrylic or lexan sheet, or tempered glass, attached to the front of the cabinet, which performs similar function to the wings sometimes seen on TQWT cabinets?
Has anyone done this? Will this help acoustically?
Planet10, what do you think?

The box in the picture is 9 x 9 x 48 inches fyi.

Quick question. What exactly do you expect to gain by making the baffle step corner frequency lower? It's just going to increase the size of the coil in your crossover that does baffle step duty. And generally, narrow cabinets image better because of less time smear. The ideal speaker has no baffle and is just a point source in space.

And a quick opinion. For something like that to work it's best, it would have to be curved back. Straight, flat baffles with no depth result in a seriously ragged frequency response. The reason why isn't exactly obvious, and can't be modeled in theBaffle Diffraction Simulator because that assumes your speaker cabinet has unlimited depth. But for a flat baffle with no depth, the transition from 2 pi space to 4 pi space happens over a shorter frequency range because all of the sound wave is released immediately upon hitting the edge. The frequency range is longer in a traditional box, because some of the sound waves travel down the side of the enclosure after hitting the front edge.

Curved wings work better however because the sound wave is released gradually as it goes around the corner. What it gives you then is a smoother 4 pi transition that has less upper frequency ripple in the response. A traditional baffle step network can then do a more controlled compensation without dips in the 1khz to 5khz range.

Just an opinion, and maybe not even right.

John

[bzdang]

I was thinking in the range of 5/16" [8mm] to 1/2" [12.7mm]. Hope it's not too expensive or the WAF goes out the window.
Here's a slightly better rendering....

[bzdang]

Thanks for your post, I'm learning as I go.
I've been exploring the possibility of pushing the corner low enough to take advantage of a designed-in hump in the bass response and thus avoid electronic BSC. Don't know enough about this yet.
No coils involved, I'm using DSP active crossover from kxproject.
But if I can do a good enough passive crossover then I can cut them loose from the dsp computer crossover and move them upstairs to the livingroom. BTW, having kxproject dsp drivers is like a poor mans omnidrive for messing with crossovers, timedelay and eq .
Hadn't been thinking about ragged response though, I wonder if I can bend up some curved wings.
Thanks for the discussion and the link. I think that I'll be looking for more info on diffraction before I proceed.
Here's an image of something ugly that may have less diffraction issues....

[Hybrid fourdoor]

Slightly off topic, but for the JPG above, is that straight output from your modeling program or did you manipulate afterwards in Photoshop or something?

Reason I ask, is because your shadows look really good, like the fade is consistant.

Wait, nevermind, I just looked at some of my own renderings and they look the same. At my house (on Win2K) whenever I look at renderings like that is dithers the shadows, so that there are gradiated lines, but here at work (WinXP) the shading is consistant and smooth.

I guess its something in the way XP and 2000 handles pictures. I only got the problem in JPG and a little in PNG's. Bitmaps were always OK. I'd say maybe its the color settings (24bit at home), but I didn't have any problems after rendering in 3dsMAX, only afterwards when I would process under Photoshop or Microsoft Photo Editor using anything higher than 2:1 compression (which would yield 100K+ pictures )