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Cbx2501987

Electro voice interface c ii — refoam

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Hi guys,

 

ive got a pair of the electro voice interface c series ii that are suffering from the degraded foam issue.

 

ive had a look online for foam replacement but don’t know whether to just get the foam surrounds or also the gaskets and other bits available in the kits. Any recommendations on how to proceed.?

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Can you provide a link to the kits in question? I’ve restored a few Electrovoice speakers in the past. 

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If your just doing the woofers just get the surround foam 

Screenshot_2019-08-10-13-15-19.png

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Posted (edited)
4 hours ago, Cbx2501987 said:

 

From what I recall, the original drivers don't have the thick cardboard gaskets. In any case, this part of the driver frames are covered by trim rings:

 

Rare-Electro-Voice-Interface-C-Series-Ii

 

 

 

The main challenge with EV speakers featuring the 1.5" 'superdome' tweeter is the acoustic lens foams. The OEM replacement lenses (70534 inner and 70604 outer foams) are now discontinued (I managed to buy the last two pairs several years ago)  and without the correct lens, the tweeter won't perform sonically as intended. The inner foam lense actually covers part of the tweeter, and simply applying damping to the outer portion of the tweeter does not suffice.

 

Page 3 of this doc explains what the foam lens does, and thus why the speaker doesn't sound quite right without it:

 

http://mypicsonline.net/archive/archives.telex.com/archives/EV/Speakers/EDS/Interface C EDS.pdf

 

 

Speaker Exchange in the US have an aftermarket kit, but they themselves note that the density of the internal ring is not as per the original design, and that they only work for damping and cosmetic purposes:

 

https://reconingspeakers.com/product/ev-replacement-electro-voice-tweeter-foam-lens-70534/

 

 

Some further pics of my old EVs showing the dual density foams and extent of tweeter foam overlap (i.e. you can see that the inner tweeter foam is glued to the ridge on the tweeter fascia and overlaps the dome), and some close-ups:

 

 

 

evsale4.JPG

evsale3.JPG

 

evA4_zps13922c91.jpg

 

image_zps37c8f89b.jpg
 
image_zpsd143f670.jpg
 
image_zps7a8976a6.jpg
 
image_zps1c9df4cb.jpg
Edited by pete_mac

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I wasn't aware you could get the "superdome" lens , I fabricated a five layer one myself . It does image properly and measure pretty well up to 15 kHz.  How much do the replica's cost ? 

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1 hour ago, DEANO23 said:

I wasn't aware you could get the "superdome" lens , I fabricated a five layer one myself . It does image properly and measure pretty well up to 15 kHz.  How much do the replica's cost ? 

 

Based upon their website, it looks like they are USD $8 per piece, with an inner and outer required for each speaker, so $32 plus shipping. 

 

To to be honest, it’s a real shame that the replicas don’t use the correct density of foam to achieve the same sonic outcomes as the EV engineers intended.  You can see the difference when comparing the photos of the replicas on their website vs the pics of the genuine items which I purchased above. 

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Based upon their website, it looks like they are USD $8 per piece, with an inner and outer required for each speaker, so $32 plus shipping. 
 
To to be honest, it’s a real shame that the replicas don’t use the correct density of foam to achieve the same sonic outcomes as the EV engineers intended.  You can see the difference when comparing the photos of the replicas on their website vs the pics of the genuine items which I purchased above. 
It is a shame I had a pair of E.V Status 50's with the superdomes where one surround was good the other falling apart , I sold them thinking you couldn't get the correct stuff . Anyway I'm happy with what I came up with they sound good and image well . I also upgraded the caps inside

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Just now, DEANO23 said:
14 minutes ago, pete_mac said:
 
Based upon their website, it looks like they are USD $8 per piece, with an inner and outer required for each speaker, so $32 plus shipping. 
 
To to be honest, it’s a real shame that the replicas don’t use the correct density of foam to achieve the same sonic outcomes as the EV engineers intended.  You can see the difference when comparing the photos of the replicas on their website vs the pics of the genuine items which I purchased above. 

It is a shame I had a pair of E.V Status 50's with the superdomes where one surround was good the other falling apart , I sold them thinking you couldn't get the correct stuff . Anyway I'm happy with what I came up with they sound good and image well . I also upgraded the caps inside

 

Cool - I also had a pair of the Interface 1 series II and they were great speakers. I’m not surprised that you like them! Good to hear you’ve done the caps too. 

 

Dad has a pair of Interface 2s or 3s with the passive radiator, and they are a good speaker too. That’s where my last set of original replacement tweeter foams went. 

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Posted (edited)

I got them for $100 which isn’t too bad considering. Is it safe to say they’re worth getting refoamed??,this model is supposed to have the external eq box but the seller didn’t know if it originally had one, the original owner passed away and im Assuming he was using a NAD 3300 to replicate some qualities of the eq box.

 

the dust cap is huge is it better to align with shins via cap removal or the battery method for this woofer?

 

deano I’m in Melbourne did you have any leftover of the foams you used to make your tweeter surrounds?

Edited by Cbx2501987

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20 minutes ago, Cbx2501987 said:

I got them for $100 which isn’t too bad considering. Is it safe to say they’re worth getting refoamed??,this model is supposed to have the external eq box but the seller didn’t know if it originally had one, the original owner passed away and im Assuming he was using a NAD 3300 to replicate some qualities of the eq box.

 

the dust cap is huge is it better to align with shins via cap removal or the battery method for this woofer?

 

deano I’m in Melbourne did you have any leftover of the foams you used to make your tweeter surrounds?

 

I'd suggest trying to find an EQ box in future - they have a low-pass filter as well as enhancing the bass response.

 

Here's a pic of the rear of my old unit - note the writing on the rear:

 

"THIS EQUALIZER ONLY FOR THE INTERFACE:A SERIES III, B SERIES III, OR C SERIES II SPEAKER SYSTEMS INDICATED ON FRONT PANEL

 

 

evA10_zps9daef1c9.jpg

 

The manual says:

 

"Interface B series III and Interface C Series II use the same equaliser. Therefore, in a system set up for Interface B Series III, Interface C series IIs may be added to the same amplifier and will receive the proper frequency contouring.

Not unexpectedly, the capabilities of other equalised Interface models are best realised by using the equaliser specifically designed for each system. The deviation from ideal depends on the particular model.

The Interface A Series III is not endangered by the Interface B Series III equaliser as long as very low bass (around 30hz) at the highest listening level is avoided. Frequency response from the 40-80hz range will be depressed about 3/4dB and approximately twice normal power will be fed to the woofer below about 32hz.

Interface D is not endangered by the Interface B Series III equaliser. However, response below about 28hz will be depressed about 3dB and response in the 40hz to 80hz range wil be emphasised by about 3/4dB."

 

 

Re: refoaming the surrounds, I've always done them by feel, with a quick check via a battery to ensure there is no rubbing. No need to shim the EV drivers IMHO.

 

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Posted (edited)
5 hours ago, Cbx2501987 said:
I got them for $100 which isn’t too bad considering. Is it safe to say they’re worth getting refoamed??,this model is supposed to have the external eq box but the seller didn’t know if it originally had one, the original owner passed away and im Assuming he was using a NAD 3300 to replicate some qualities of the eq box.
 
the dust cap is huge is it better to align with shins via cap removal or the battery method for this woofer?
 
deano I’m in Melbourne did you have any leftover of the foams you used to make your tweeter surrounds?

I actually made mine I'll have a look but I do know that it took four to five layers , mine are pictured with the blue surrounds . There are different diameters on those super tweeters so you need to measure the diameter of the tweeter then the whole surface diameter .
You won't believe this but I got mine free as long as I did restore them and post a picture to a girl whose grandfather had passed away . He owned them. I wasn't surprised they'd sound good , those woofers are really good . Yes I did mine by feel as well, it's important you put a low voltage input through them to align them . I wouldn't take the dust cover out , to me it would invite trouble replacing it. I'll look tomorrow if I have any surrounds

Edited by DEANO23

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I haven't, I could make some at a modest fee but as I said those superdomes have different diameters and you'd have to accurately measure them . P.m. and I'll give you a phone no and discuss it e.g. method etc

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1 hour ago, DEANO23 said:

I haven't, I could make some at a modest fee but as I said those superdomes have different diameters and you'd have to accurately measure them . P.m. and I'll give you a phone no and discuss it e.g. method etc

 

Hi mate, re: the above, are you sure? All of the EVs with the Superdome tweeter that I’ve owned have featured the exact same tweeter with no variation in diameter or sizing. This is consistent with EV making only one set of replacement OEM foam tweeter surrounds and acoustic lenses.

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I'll measure mine you measure yours and the one with the biggest wins, lol. Now if you give the measurements just with a tape measure will do . I might be and hope I'm wrong I would hate to measure and cut 10 circles with 10 insides and then find out they are the wrong size. I use a heavy cloth with is layered with a viscous kind of glue that doesn't harden . I can get a black with the same kind of pattern . 

I thought I'd read in their history page that there was two different sizes , I know the magnet on mine is no where as heavy as the the two I sold. 

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I will get that measurement soon, these are probably the heaviest speakers I’ve encountered, getting them into storage was a real pain- literally. 

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