Interesting new fullranger from CPC (UK)

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I've got a couple of their 5 1/4" full-rangers, though it took me an age to find out what they are (thanks guys!) as I bought them in an unlabelled box from a local electronics supply shop. They're not bad at all for the low, low price -the magnet's massive. I use them for testing amplifiers etc, on the basis that if they go bang, my wallet hasn't wilted. They reside in a pair of traditional (vile design, but it doesn't matter) Voigt Pipe cabinets in the garage, made entirely of polystyrene. Sound is surprisingly decent. In fact, it's pretty good! And at that price, you can't really go wrong, can you?
Best
Scott
 
This looks remarkably like the driver sold under the Radio Shack label as the 40-1271c. I picked up a n-name pair of these in viking cabinets for about $8.
If they are the same, they have a QTS of about 2.01 (yes 2.01) and on anything other than open baffle they boom.
However, no real bass to speak of. They are more mid/tweets. They could sound ok though with a helper woofer (not subwoofer).

I put mine on small OB's, and they are just OK. HF extension seemed rather good, but they had no body whatsoever. (I don't think larger baffles would help much).

Tom
 
Amen. It was actually our mutual friend above who put me on to this via his most excellent website -a Russ Andrews notion of rapid energy release preventing time-smear or some such problem due to resonance build-up in the panels. Now, I can't say I'm enarmoured of all of Russ's wilder flights of fantasy, but I have to admitt that this one works well. The trad. Voigt Pipe will never be a spectacular cab. -that point cripples it (though in passing, the FE206E looks like a passable match in Martin's MathCad sheets -better than the 207E), but with these polystyrene panels, the results are more impressive than I would ever have believed until I tried it. Pity more commercial speakers don't do it, but movement requires a certain, shall we say, delicacy.
Best
Scott
 
>The only commercial design that I know of was the one using a single Jordan driver and no crossover. I would love to have heard those although I know they lacked bass!

Hi Nuuk

I've heard these and they sounded very clean. Limited in the bass (but then they were using the JX92 in only 3 or 4 litres, so it would roll off below 100Hz anyway). I prefered them to the same driver in a traditional MDF box, which sounded slow and woolly by comparison.

Wharfedale produced some designs in the 80s which used polystyrene skinned with formica. Never took off, as far as I know.

I've also heard RA's implementation of his idea using Torlyte. Again, very clean sound at high volumes and disconcertingly light when you moved the boxes around. A pair of my enclosures use his chipboard and insulation board construction method.

There is a silver foil-covered building insulation board which is available up to 3" thick which looks like it would not be difficult to work with. (This could be the subject of a whole new thread.)

Colin
 
A pair of my enclosures use his chipboard and insulation board construction method.

As do my current IPL A2 enclosures! ;)

There is a silver foil-covered building insulation board which is available up to 3" thick which looks like it would not be difficult to work with. (This could be the subject of a whole new thread.)

And you can buy foam of different density too! It is made primarily for the mock-up industry, eg for making a model of a product for display purposes, or making a design like a car, just to see what it looks like.

Somebody kindly sent me some samples of this stuff and it is a lot more robust than the building type that we have used so far. You can even screw into it! It's more expensive though and I am still looking for an outlet where you do not have to order in bulk quantities (unless we can convert everybody and do a group buy)! :att'n:
 
Colin said:
>There is a silver foil-covered building insulation board which is available up to 3" thick which looks like it would not be difficult to work with. (This could be the subject of a whole new thread.)

Colin

Perhaps you missed the "my Fostex FE108 Sigma Project" thread. It's probably back five or six pages by now. I thoroughly reveal my ignorance, but there are lots of pictures. I've already built five prototypes out of that very same foam (1/2 inch, though). In my last prototype, I used a piece of 4 inch PVC pipe for the compression chamber. I just wish I could get someone else to listen to these. I'm not sure I can trust my judgment, given the "it's my baby" syndrome.

Doug
 
Taperwood said:


Perhaps you missed the "my Fostex FE108 Sigma Project" thread. It's probably back five or six pages by now. I thoroughly reveal my ignorance, but there are lots of pictures. I've already built five prototypes out of that very same foam (1/2 inch, though). In my last prototype, I used a piece of 4 inch PVC pipe for the compression chamber. I just wish I could get someone else to listen to these. I'm not sure I can trust my judgment, given the "it's my baby" syndrome.

Doug

Question: do you like the sound?
If your answer is yes, who cares what other people think? We all like different things anyway. That's the hard-nosed reply. But then again... I know the feeling. It's nice to have other views too. When I stuffed my Tannoy Golds into an 8 foot Voigt pipe (before I knew any better), I loved the sound right up until I measured it. Then, just to clinch things, a friend asked very sweetly why she couldn't hear several voices she'd heard before on the recording though a cheap pair of Wharfdales.
For what it's worth though, I still reckon, if it's the X-baffles you built (?) you're onto something good with those.
Cheers
Scott
 
Oh yeah, Scott, I love the sound, but as you pointed out, it was a friend who clinched it for you that something was not quite right. My wife is no help. She listens for five seconds when I AB for her, says "that one," and walks out of the room. Anyway...

Yes, I'm still futzing around with the X-baffles. Prototype #3 is still my best effort, but #5 reveals more clarity in the mid-range at the expense of bass extension, losing quite a bit below 100hz.

And I apologize for completely hijacking this thread.

Doug
 
Nuuk said:


As do my current IPL A2 enclosures! ;)



And you can buy foam of different density too! It is made primarily for the mock-up industry, eg for making a model of a product for display purposes, or making a design like a car, just to see what it looks like.

Somebody kindly sent me some samples of this stuff and it is a lot more robust than the building type that we have used so far. You can even screw into it! It's more expensive though and I am still looking for an outlet where you do not have to order in bulk quantities (unless we can convert everybody and do a group buy)! :att'n:

The other day I saw some material that was 1/4in ply faced (both sides) with about an inch of pink polystrene foam in between, it even had intermittent glued? 1/16 inch wood running from the front ply to the rear ply segmenting the foam into cells. I have no Idea what it is used for...a sample was at the UT Austin materials lab. It looked expensive.... I lusted appropriately.

Sean


Sean
 
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