Crooked subwoofer?

[ericanderson]

Re: Honesty requires I say


> . . . that I am not sure. I remember looking
> at some such catalogs as a 17 YO college
> freshman, but whether it was Allied Radio or
> something else, I don't know. It contained
> Lafayette electronics and, among other
> things, Utah speakers.

> Dan
how about Heathkit dynaco? anybody remember those cataloges?

[marlboro]

NOpe...You're not old then


Lafayette came after Allied Radio.

My uncle was a UMASS electrical engineer who built his own speaker systems in the 1940's and 50's. He left a $15K job in industry(GE) in 1955 to take a $2K job at UMass as a professor of Electrical Egineering.

When we went up there, he had these catalogues lying around, and around 1957-1958, I would page eagerly through them for the parts and the kits.

Marlboro

[bogie]

Re: Actually...


I'm sorta intrigued by what a Q15 in a high Q sealed box looks like when you turn it into a very long, very large port...

[Wolf]

I was 14! *NM*

[AJ]

Re: Wholly Molley is you guys Auld!


Uhh... I was 2.

[bill]

Re: Honesty requires I say


> . . . that I am not sure. I remember looking
> at some such catalogs as a 17 YO college
> freshman, but whether it was Allied Radio or
> something else, I don't know. It contained
> Lafayette electronics and, among other
> things, Utah speakers.

> Dan

OK, I was 41 in 1992. I remember waiting with bated breath for the Allied, Lafayette and Heath catalogs when I was a kid (in the 60s). My first kit was a Knight-Kit Ocean Hopper superregenerative receiver. I think I got it when I was 13 or 14.

I didn't have the money for a decent stereo in those days, and if I'd had one, my mother wouldn't have permitted me to play it at anything approaching teenage sound levels. That had to wait until I got to college.

So no, Dan, you're not old.

Best regards,
Bill

[Pete Schumacher]

COME ON GUYS!!!!


That's just a coiled up version of the patented BOSE wave cannon subwoofer.

[marlboro]

yeah...you're old.... *NM*

[marlboro]

Geez! I have kids older than you! *NM*

[daylbrinkman]

Re: COME ON GUYS!!!!


> That's just a coiled up version of the
> patented BOSE wave cannon subwoofer.

Exactly. But do you think the design is close enough to reality to bother trying to build it?

[waynew]

Re: COME ON GUYS!!!!


A tang band 4" sub and some Schedule 40 PVC in 4" variety would be the easist way to find out. 6" pvc gets pretty spendy. Have at it and tell us all how it works. Personally, I get a kick out of doing those kinds of things. Sometimes its just a lot of fun to expirement.

[marlboro]

If you really want to do it....


Go to this website:

<A HREF="http://www.t-linespeakers.org/">http://www.t-linespeakers.org/</A>

There are some interesting designs there, but I don't think any of them are actually subwoofers, unless your definition of sub woofer is quite different than mine.

Marlboro

[Dirk]

Re: If you really want to do it....

Provided Link: http://t-linespeakers.org/projects/steve/index.html


> Go to this website:

> <A HREF="http://www.t-linespeakers.org/">http://www.t-linespeakers.org/</A> There are
> some interesting designs there, but I don't
> think any of them are actually subwoofers,
> unless your definition of sub woofer is
> quite different than mine.

> Marlboro

I'm pretty sure this guy qualifies as a sub:

[kene]

Re: That's all fine and good, but...


> That all rings of "transmission
> line" to me. They're just treating both
> the front & back wave.

If the longer tube is in fact being used like a transmission line I would suspect a not-completely-bunk application here would be to try and emulate the operation of a 4th-order bandpass enclosure, or a 6th-order if the longer tube is left unobstructed (and then no longer a transmission line).

It could be a fun project to do in a quirky kind of way, but in practice I'm given to suspect that the appealing points of transmission lines versus band-passes would serve to undermine each other. I always thought the idea of transmission lines was to eliminate backwave interference with the driver to reduce transient smearing, but you're going to lose all that as soon as you pass the front wave through the bandpass filter anyway.

I suppose if you REALLY wanted to do a 4th-order bandpass and were REALLY stuck with just one specific driver and you REALLY REALLY REALLY wanted to get that last Hz and 0.1dB, then using a transmission line wouldn't elevate where the driver/rear chamber would achieve resonance as much as any given sealed arrangement, so you could tune the filter chamber to have less loss in efficiency. Speculatively that makes sense, and from a screwing-around standpoint you could see if you can get a 4" in an enclosure with a response that peaks at 25Hz or something (and a whole 61dB 1W/1m output instead of 60 or 60.5).

[hand123]

And here is the article I've saved since 1992. I had hopes of building this one day until I saw this thread today and learned about Lirpa fools. I've been a fool for a long long time.