Subwoofer for vintage speakers?

6V6dude

Member
2014-09-09 11:07 am
I have Goodmans tweeters and Wharfedalle 10 super speakers in nice old 50's big boxes. Sound is fantastic but I'm lacking sub bass, maybe from 40Hz down. The stuff you mostly feel, not hear much. I think it could be due to my room acoustic/size. So I want to build a subwoofer but all I find is box ideas for thumping techno music which is what I don't want. I need it for Jazz, vintage rock etc. I've got some Alnico 12" speakers I could use but no idea what type of enclosure would do it right.
Any ideas or links would be appreciated.
 
How do the surrounds look on those Wharfedalle 10 super speakers? I've had 2 pairs, and all the surrounds were porous / open / dried out. Fixing that with some goo might be enough for you, see the link (I used diluted rubber glue on my surrounds).

Wharfedale Super 8

"coating the surround gave an immediate increase of 5-6 dB in response"

Years ago, I tried running my super 10s with Alnico 12" (also Wharfedale*), but gave up on them / moved on to more modern units. Particularly for sub use, new stuff is usually better. I doubt many vintage 12" are optimised for <40Hz.

Where are you?
Do you have any measuring gear?
What's your budget?
How will you cross over?
Size limit?
Tools / cabinetry skills?

*old Wharfedale stuff is pretty widely available in Australia, I think due to
a) being a British colony
b) the debt & various restrictions Britain had been forced to accept in WWII

...so all the 50's - 70s's gear floating around is from the UK, rather than the USA or Europe.
 

6V6dude

Member
2014-09-09 11:07 am
Probably best you see my post here http://www.diyaudio.com/forums/full-range/287870-goodmans-trebax-wiring.html#post4636763
That'll show you what I have. These are rear vent boxes (have slots cut out at rear across the middle).
The surrounds on the Super 10's are clean. Never been coated, I'm not sure if coating would do much specially when the boxes aren't sealed.
I might do xover, I have nice old Hokutone xover that I think would work nicelly on sub but not sure if I really need sub as such. I think I just need acoustically make the bass more pronounced (louder) because and now I'm sure it's due to a room size and is full of furniture too. I tried them in very large room, no carpet and the bass was about right there. Not thumping, just more like in a concert, big and open but still tight.
 

Those 10" are familiar.

The surrounds on the Super 10's are clean. Never been coated

Mine were clean too, but that doesn't strictly mean they were never coated. They may have had a waxy / oily treatment that dried up over the decades.

I'm not sure if coating would do much specially when the boxes aren't sealed.

How translucent is the surround when you hold them to the light? Can you feel warm air when you blow through the cloth?

If so, I think it will make a difference. The rear radiation of the speakers has a long path via the slot before it can cancel the radiation from the front of the speaker. It only has a short path if it can cut through the surround.
 
Why? It's what it is in today's parlance same as Harry Olson's 1950 high aspect ratio 'ported' cab is normally referred to as a MLTL nowadays: http://ayumi.cava.jp/library/olson.pdf

GM

I was implying the name should not have changed from the original. That Olson is not the same type of enclosure as that Jensen TL. The Olson looks like a simple BR enclosure. The Jensen looks like a series tuned BP6 or tapped pipe enclosure.
 

6V6dude

Member
2014-09-09 11:07 am
Those 10" are familiar.

How translucent is the surround when you hold them to the light? Can you feel warm air when you blow through the cloth?

Can't blow through them because I've all ready install them. It's basically a clean fabric, I can see slightly through so I imagine they would let some air through but if enough to effect anything I'm not sure. They made them this way likely for a reason just like they put the foam around the center tweeter cone. I imagine that's there to stop oscillations at certain frequencies. If you lookup Google images you can find few of exactly the same types, also with clean surround.
When I get a little time I'll experiment with blocking the rear vents and see what happens. Maybe projecting only forward would do better in my room. They do sound perfect when I stand about 1 meter from them but further I go, the bass and fullness of the sound starts dropping off rapidly.
I'm just thinking that because I have big Advents in a same spot and they sound just fine. But yeah the Advents are sealed box so I guess they don't depend on acoustics so much like vented speakers.
 
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