902-8A or 902-8T for VOTT project..??

[GM]

You're welcome!

I'd say so, for sure I do, but it's as much a personal preference as what is technically 'best' for a given app, so each has to find their own way to audio nirvana.............

GM

[atilsley]

Thanks.

As I mentioned earlier, I enjoy a large, rich bass....hence me looking at a bigger Altec design.

I recently built a new bass cabinet for the US rep of GOTO, Ming Su. I only heard the cabinet with my Tannoy HPD 15-inch driver, but it sounded great. (See pic of one MDF cabinet in construction, plus the 3D computer image I prepared, with inspiration from the Jensen Imperial - lying on its side.) Interestingly, Ming recommends the 416 15-inch driver for those folk who can't afford the very expensive GOTO unit....

I'm after that full/rich sound in the Altec...with a response from about 30Hz flat. Am I on the right track with the 828 cabinet?

What are you using?

Andrew

[theebadone]

Ooo, 30 hz. is gonna be tough in the A-7, unless you plan on running a sub. You might wanna check out the 9846 model also. I like the Altec woofers because of their ability to give you the nice tight, controlled bottom end that they give, so if they don't go much below 50hz. its no big deal. The 411-8A might be the woofer that will serve you best, but it was only offered in a sealed enclosure, but capable of 18hz. Very nice driver, and still available from G.P.A.

[Mustang Marvin]

Maybe this is a little off subject but, is MDF preferable over plywood (Baltic or Russian Birch). Is it just personal preference or is there another reason. I understand MDF is more ridged and dense. I know some DIYers would only use the Birch plywood.

Since experience is the best teacher I would like to hear from those that have built cabinets. I know a very good cabinet maker and he has built speaker cabinets and recommends MDF. The MDF is what I'm leaning toward, but I always enjoy the suggestions and comments from the guys on this forum.
Thanks

[MikeInNH]

The idea behind using MDF is that MDF doesn't add color to the sound. Solid wood and plywood may vibrate when the music is playing...thus adding sound (which is undesirable). MDF will NOT vibrate when the music is played, so it won't add any music. When playing at very loud levels it doesn't matter what you use because any vibration from the cabinets won't be heard.

[Panomaniac]

And the counter argument is....

Even MDF vibrates. And when it does, it sounds bad. Even if low in level. Real, good, void free BB ply is the stuff to use. If and when it vibrates, at least it won't sound bad.

[GM]

And since it's higher in frequency/Q, it takes much less to quell them to below the system's noise floor.

GM

[GM]

The idea behind using MDF is that MDF doesn't add color to the sound.

MDF will NOT vibrate when the music is played, so it won't add any music.

When playing at very loud levels it doesn't matter what you use because any vibration from the cabinets won't be heard.

True, worse though is that it removes something from the sound due to its low MOE and high mass that makes for a wide, low Q *resonant* BW, so unless the cab's intended pass-band is completely below the cab's construction Fs it will vibrate to the music for much longer periods than higher MOE materials such as BB ply. For those that want to have their 'cake and eat it too', building with at least 1.125" thick MDF gets you 19 mm BB ply's extreme rigidity and the MDF's massive density to quell any 'ringing' in the 20-20 kHz BW with the trade-off of course being ~like concrete in weight.

Yeah, 'loud' will drown it out and why manufacturers could get away with such low SQ construction in the so called 'good ol' days' of low power, but the high acoustic power available today requires very rigid, leak free construction for long term good performance much to the 'bean counter's' chagrin.

Anyway, this subject has been 'beat to death' many times on other forums with both theory and real world measurements, so 'color' me done and anyone wanting to delve into all the caveats of box material choices can Google it, though here's a 'teaser' (the rest of his website is a 'must read' also IMO): Loudspeaker construction

GM

[Audio_by_Goodwill]

I understand MDF is more ridged and dense.

It is not more rigid, it is less rigid, but it is cheaper and has a more uniform density.

[mikebond]

And the counter argument is....

Even MDF vibrates. And when it does, it sounds bad. Even if low in level. Real, good, void free BB ply is the stuff to use. If and when it vibrates, at least it won't sound bad.

I can confirm it from my own expirience - MDF is BAD! Use BB plywood only!
BTW, if you need deep bass and fantastic low mids - look at my own design:
http://www.hostboard.com/forums/alte...w-project.html
Mike