A7 Cabinet Resonances?

**Tom Brennan** · March 14th, 2006, 02:10 AM

"It may be your opinion, but you won't find a speaker cabinet designer who agrees with this statement."
--------------------------------------------------------------------------------

Maybe not today but I think speaker design was different in the 1940s, things were trial and error and if a good result was obtained they were happy.

A friend analyzed Bozak CGs many years ago and came to the conclusion that the box was deliberately designed to vibrate and help give that lush Bozak sound. Now ole Rudy Bozak knew what he was about, if the box vibrated he knew.

**Steve Mac** · March 15th, 2006, 06:08 AM

Originally posted by Tom Brennan:
Maybe not today but I think speaker design was different in the 1940s, things were trial and error and if a good result was obtained they were happy.

Well, not meaning to stir anything up and remember this is all good fun... but there were some pretty intelligient engineers back then who were all over it. I still think the 1952 Jensen Imperial Horn is the best sounding sub woofer I have ever heard...regardless of age or time.
Check out these pics:
Ikeda
Kobayash
Roggiero
Takashir
Yoshikat

Notice they used quite a lot of concrete back a good 50 years ago. But really...I just wanted to share some pics that really get me motivated when I haven't built something in a while.

A friend analyzed Bozak CGs many years ago and came to the conclusion that the box was deliberately designed to vibrate and help give that lush Bozak sound. Now ole Rudy Bozak knew what he was about, if the box vibrated he knew.

Lush? forums

Bozak s-u-c-k-s forums

OK just kidding...but if he did this then he's a hack or has a K-Mart MBA in something. Did he end up working for Bose? He obviously was uninterested in accuracy.

**Steve Mac** · March 15th, 2006, 06:15 AM

Originally posted by ngccglp:
Hi Steve,

You may be right, I always suspect its the 4 wooden strips that accept the screws of the back panel. But don't know how to solve it without making it worse. Think I'll just apply white glue all round when I have the time.

Thanks.

I've got an old 1952 Leslie cabinet with a rotating drum that had a glue joint crack...and OMG...I went nuts trying to find it. I hope you have an easier time. Good luck! forums

**jnorv** · March 15th, 2006, 09:00 PM

I had the same problem with the strips on one of my 828's. I screwed them back into place with # 10 hex head sheet metal screws on about 6 inch centers. It did not lower the WAF significantly.

Jim N

**Tom Brennan** · March 16th, 2006, 02:09 AM

"OK just kidding...but if he did this then he's a hack or has a K-Mart MBA in something. Did he end up working for Bose? He obviously was uninterested in accuracy."

You should learn a little about Rudy Bozak before you run your jibs, a little respect is in order. The man was a fine engineer who started designing speakers in the 1930s including systems with 27" woofers for the 1939 Worlds Fair. He made some of the finest direct radiating drivers and systems of his time, some would say ever.

His systems were built around carefully made 12" woofers with variable density wool cones, an aluminum midrange cone with a rubber damping compound and 2" aluminum tweeters with a damping compound and rubber "bumpers" behind the cone to control ringing. His Concert Grand used 4 of the woofers, dual midranges and a line array of 8 tweeters. A pair just sold for over $2500 on ebay.

All in all a very serious speaker designer. Somebody worthy of respect, not smart-aleck comments about K-Mart MBAs.

**Steve Mac** · March 16th, 2006, 05:06 AM

I don't though have respect for people who do not read posts carefully to determine when someone is "just kidding" and having their own opinion, expressing it and being chastised/disrespected by someone who uses and recommends spray can foam for speaker cabinets.

I hit the add reply before carefully reading my own post...see how easy it is? It was tomdee who recommended foam not you.

I will re-write this part now:
I don't though have respect for people who do not read posts carefully to determine when someone is "just kidding" and having their own opinion, expressing it and being chastised/disrespected. I was simply trying to help someone with a vibration in a speaker.

**Tom Brennan** · March 16th, 2006, 05:56 AM

Mac---Now you're being disingenous; you slam a guy then plead just kidding.

I have news for you, if you want people to understand you're kidding you first need to be funny.

**Steve Mac** · March 16th, 2006, 03:17 PM

Originally posted by Tom Brennan:
Mac---Now you're being disingenous; you slam a guy then plead just kidding.

I have news for you, if you want people to understand you're kidding you first need to be funny.

Well there's no sense in trying to keep things light here.

Look, you want to fight, fine I got no problem there. First on the subject of humor. Why are you engaging when you have none? OK, Tom now listen because this is funny..."Why don't you take a can of that expanding foam and fill up the voids and cracks in your head"

**Tom Brennan** · March 16th, 2006, 03:38 PM

Mac---Pure insult fails as wit. Like I said, if you want to be understood as being funny first be funny. And comparing Rudy Bozak to Bose and saying he had a K-Mart degree falls more into pure insult than wit.

By the way, 605As have fabric surrounds.

**Steve Mac** · March 16th, 2006, 04:48 PM

Originally posted by Tom Brennan:
"OK just kidding...but if he did this then he's a hack or has a K-Mart MBA in something. Did he end up working for Bose? He obviously was uninterested in accuracy."

You should learn a little about Rudy Bozak before you run your jibs, a little respect is in order. The man was a fine engineer who started designing speakers in the 1930s including systems with 27" woofers for the 1939 Worlds Fair. He made some of the finest direct radiating drivers and systems of his time, some would say ever.

His systems were built around carefully made 12" woofers with variable density wool cones, an aluminum midrange cone with a rubber damping compound and 2" aluminum tweeters with a damping compound and rubber "bumpers" behind the cone to control ringing. His Concert Grand used 4 of the woofers, dual midranges and a line array of 8 tweeters. A pair just sold for over $2500 on ebay.

All in all a very serious speaker designer. Somebody worthy of respect, not smart-aleck comments about K-Mart MBAs.

Smart aleck? naw...
Bozak? I know all about him, I've studied these
cats for years and have tremendous respect for them all. And unlike you, I bet he had a sense of humor.

I don't though have respect for people who do not read posts carefully to determine when someone is "just kidding" and having their own opinion, expressing it and being chastised/disrespected by someone who uses and recommends spray can foam for speaker cabinets.

Also, remember your contradiction:
You have just talked up a speaker designer from the 30s but earlier in a post, which I did not agree with...you said and I will now quote a second time:

Originally posted by Tom Brennan:
Maybe not today but I think speaker design was different in the 1940s, things were trial and error and if a good result was obtained they were happy.

So, truth be known, I was really the one sticking up for Rudy Bozak and all of the fine engineers of yesteryear and it was you sir who was not kidding when you were dismissing the capabilities of a tremendous period of brilliant audio engineering research and developement.

Good luck wriggling out of this...

Thread: A7 Cabinet Resonances?

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