Reconing A Speaker

[tube power]

I'm going to take a crack at this.
I have a Sheffield 1230 that functions, but someone "repaired" the foam surround with a caulking gun and putty-knife. Absolutely aweful. Surprisingly the speaker sounds pretty good, no scraping when compressed.
But I don't trust it, of course.

I found this...

Legacy Sound Service : Peavey Sheffield 1230 "Turbo" - LSS Recone Kit for 12" - 8 Ohm [LSS-PV1230TRBO-8] - $31.00

But I'm not sure I need to do the whole thing.

Here it is...



Maybe I could just do the foam surround?

[Jazz P Bass]

Isn't it amazing what people will do?
And it works!
My concern would be getting the new surround to attach properly.
That's a lot of goop!

[52 Bill]

Does that speaker have a foam surround? It looks like a standard paper cone with edge doping.

[tube power]

It does.
I did some studying, it's an angle attach. I ordered the surround, a new dust cap
and a new gasket, in case I destroy it getting all this undone.

I'm taking the extra step of removing the cap to shim the coil while replacing the surround.
Some online stores don't mention that but I'm convinced it's crucial to a proper fix.
If the cone gets glued in even slightly off center the coil will rub on the magnet and burn up.

Total of $22 and probably an hour's work.

[J M Fahey]

Hi tubepower, congratulations on your guts.
Now on to the job:
1) You can't "just replace the edge" because that is a single-piece cardboard cone, as 52 Bill noticed.
2) You *may* use a cloth edge, and dope it by brushing with a mixture of white glue and water
The idea is to keep resonance and flexibility not to far from the original.
3) If you use a soft cloth edge or even werse a foam one, the speaker can't be used in an open baffle; maybe it can be used on a closed one (preferably not vented)
Good luck.

[tube power]

It had a foam surround, just like my other 1230.
I already replaced the surround, works great.

[J M Fahey]

Congratulations on your successful transplant.
Besides that, let me say that Sheffield1230's do not leave the factory with a foam edge, although, of course, they can acquire one later.
Peavey itself states:

Cone: Paper with treated paper edge

, which can be clearly seen in:

Maybe the other one had already been repaired before.

[tube power]

Yeah, that's what mine look like.
So i performed an improper repair!
So this speaker may self destruct?

[J M Fahey]

Problem is that its suspension is too soft (that's the idea behind using foam) and the cone may move "too much" on deep bass.
If it's in a sealed box, no big trouble, because the cone must compress or suck the aire trapped inside it, which effectively "brakes" it; but on a combo or open box, you may get into trouble.
¿Can you provide a picture of what you actually used?
Worst case, you are $31 away from a properly reconed one, no that big deal.
If, instead of foam, you had purchased a cloth edge, it can be made more rigid by choice of doping material.
In fact, EVM12L, JBLs and a couple other high end speakers (which aren't *really* guitar speakers but which can be used as such), do have cloth surrounds ... and suspensions relatively rigid.
But foam, belongs in your Hi Fi.
I do use foam on some of my 10" woofers, which I use on amplifiers for double bass, Reggae and Fusion bass players, but not for other "rockier" music.
PS: maybe someday you can buy a regular paper edge cone, cut just the surround with scissors and use that "ring" to replace the old one. I have done that before, with good results.

[Intergalactic Tourister]

Is foam edge a relatively new idea (1970s or 80s)? I have old Jensen "High Fidelity" speakers from the 1960s that are all paper- similar to guitar amp speakers. Also I notice on old hi-fi consoles they are paper as well.

Isn't there a difference between the raw wattage of instrument amplifiers and hi-fi amplifiers? And could the implementation of foam edge speakers have something to do with how instrument amps are becoming more digitalized and processed to be able to function properly with foam edges?

So if theres any truth to that, I don't know, but maybe thats why the speaker works well in your case. What amp are you using to test the speaker out with?

EDIT: Oops, old thread... sorry

[J M Fahey]

Ooops ! Many different questions !!

Is foam edge a relatively new idea (1970s or 80s)?

Yes. Don't know who actually invented them, but the idea of using heavy cones , very soft edges and suspensions, loooong voice coils, was popularized by AR and their "Acoustic Suspension" bookshelf Hi Fi speakers.

I have old Jensen "High Fidelity" speakers from the 1960s that are all paper- similar to guitar amp speakers. Also I notice on old hi-fi consoles they are paper as well.

True, the famous and iconic Celestion G12 speakers were invented as a 12W speaker for "Consoles", meaning an old (obviously tube) audio system with an integrated radio and a record player.
The very best also included a TV (you could buy one of them or a car, the price was similar)

Isn't there a difference between the raw wattage of instrument amplifiers and hi-fi amplifiers?

A watt is a watt, but instrument amplifiers expect to be overdriven, and Hi Fi amps expect to be used at 1/10 max power, to have 10 dB extra for music peaks.

And could the implementation of foam edge speakers have something to do with how instrument amps are becoming more digitalized and processed to be able to function properly with foam edges?

No, don't read too much into that.

So if theres any truth to that, I don't know, but maybe thats why the speaker works well in your case. What amp are you using to test the speaker out with?

As I said, I use them only in a very limited area: very deep bass, flat response, no need for very high acoustic pressure. (i.e. no metal, etc. but Jazz, Tango, etc.)
As an example:
Jazz/Tango:

Symphonic:

I'll take a picture of one of the foam edged speakers used there and post it.
A client specifically requested a 2x10" box, he fell in love with one he heard live, so I'll have to build a couple.
But remember: we are talking Bass only, never guitar, and moderate sound levels.

[tube power]

I've been using mine in a closed cabinet as suggested,
just a carpeted, pre-fabricated "kicker box" made for using a 12 inch sub behind the seat of a pickup truck.

I use it for band rehearsals with a Blackheart Handsome Devil 15 watt tube amp.
Sounds so good I'd actually use it if we played a very small room.

It's been going strong with no issues since a few days after I posted this. (8 months)
I do not crank the amp to ten, but I rarely do that live either with my gigging 2x12 cab.

[jrfrond]

Yeah, the old Acoustic Suspension system with bumped backplates and foam surrounds. Inefficient as all hell, and the result was what I call "Jukebox Low-End", a really boomy 100Hz type of sound that I just can't stand. To my ears anyway.

[Intergalactic Tourister]

Interesting, thanks very much.

Usually I notice many threads will end without any resolve. I appreciate the fact that this thread didn't end with tube power saying, "So this speaker may self destruct?"

I'm not as technically savvy as most on this forum hence all the questions... but I do experiment with the placement of speakers rather than using different speakers simply because of size and cost (or I can't afford them and not enough space).

I have another old pair of speakers I've had for years but know nothing about (no brand name?). I'll post a picture here if any one is curious to see them or offer any knowledge about them. I've used them for instruments- but they could be old hi-fi speakers. They have a unique design though.

Also, I have been reading an old book on the subject just as a curiosity... and it mentions how using, perhaps, a cabinet of about 12 to 16 6" speakers equates to about one large 15" speaker in terms of low frequency. The logic used is that the cubic volume of air being pushed by multiple 6" speakers will equal to that of one 15" speaker but the multiple 6" speaker will also provide the mid to upper freqs as well.

In other words, at low freqs the multiple 6" speakers act as one large speaker. I'm sure it's been done before but probably not with foam edged speakers. Maybe it could work for guitar this way... perhaps because the logic goes on to include that each 6" speaker will handle a very small portion of energy so that distortion is kept to a minimum. There is no speaker sub-forum here but I wonder about the pros and cons of this, as well, and the experiences of others.

Thanks

[J M Fahey]

I'm sure it's been done before but probably not with foam edged speakers.

It has been done in a very famous and unusual speaker, google "Bose 901" , they used nine 4" or 5" foam edged speakers in a weird direct/reflecting array.
They did sound *very* good, real flat and smooth.
There was also an all frontal shooting version for PA, at one time Frank Sinatra used them, quite an endorsement.
One unusual fact (among many others) was that the drivers were 1 ohm impedance, with all 8 or 9 connected in series for a standard 8 ohms total.