DIY? Electro-Voice 30w (x4)

[Peter Loeser]

My dad has had a pair of Electro-Voice 30" woofers tucked away for quite a few years collecting dust, and may be inheriting two more in the near future. We've talked a few times about doing something with them, just never got around to it. I know they're not going to out-perform modern smaller drivers for sub applications, but still thought it might be fun to build them into something. If for no other reason than 4 30" woofers would just be fun to look at.

Any ideas on what size enclosure I'd need to get any kind of decent performance out of these? I may have the space behind my screen. Looks like they're designed for a sealed enclosure. What about dual opposed? Data sheet attached.

 

[Sonnie Parker]

This is where we need someone like Mike Paulton who knows WinISD (or whatever folks are using these days).

 

[Tonto]

This article is a good read. If you have the time to cipher it! I see a lot of the terminology in both articles so it may be easier than we think.

http://forum.speakerplans.com/guide-to-winisd-pro-and-hornresp_topic1314.html

Since they are low powered drivers, you may like a folded horn type of cabinet. To get down to 15-20 Hz with good output in a standard cabinet, you are talking about 700 cubic feet if I'm reading correctly. I bet horn loading with a small amp would blow you over! Especially if you corner load them (which will let you cut down on size also).

And don't worry about warning us when you fire them up...we will hear them!

 

[chrapladm]

According to the PDF these drivers like large enclosures. Optimum being 50cuft. There are quite a few drivers out there that members stuff into tiny enclosures because of limited space and with EQ it works fine. The problem with that is you still will need a lot power to use that drivers usable excursion.

I dont see the T/S for this driver other wise I would simulate it for you with the suggested RMS power. It lists a 60watts rms figure with a 2.5" coil. So placing this driver in a small enclosure and feeding it a LOT of power to make use of usable excursion wont be wise for longevity. BUT devising a good plan is always best.

Going by the PDF simulation I would suggest no smaller than 12.5cuft. I myself would then use whatever amplifier and just be smart about pushing the driver to its limits.

So do you have T/S parameters for this driver?

If not I might be able to find them.

And regarding a horn suggestion, you would need a massive cabinet for this driver. Most likely it has a weak motor for its size so your going to be looking at something like 2000L at least and thats not going to get you into 15hz area either. Most horns out there that are designed for 15hz are using much smaller drivers with very strong motors. One 18 and its about 700L or a pair of 12's and its about the same size. A pair of very powerful 21's and that cabinet is 1600L and 20hz. So horns are probably out of the question unless you have a spare room for the enclosure. IB would be great for these but lets get T/S first and go from there.

 

[Peter Loeser]

Couple threads I found. The data seems to agree.

http://www.diysubwoofers.org/cgi-bin/talkrec.cgi?submit=lt&fid=f1&msg_num=32882

Fs = 16 Hz
Qes = .3
Qms = 2.61
Qts = .27
Vas = 210 sq ft
no = 5 percent
Vd = 84.3 sq in
Sd = 562 sq in
Xmax = .15 in
Pe (max) 60 watts
Zmax = 8 ohms
Re = 4 ohms


http://forums.audioholics.com/forum...0w-30inch-sub-woofer.46968/page-3#post-459101

Fs......=16hz
QES....=.3
Qms....=2.61
QT.....=.27
Vas....=210 ft3
Mo.....= 5% half space
Vp......=84.3 in3
Sp.....=562 in2
xmax....=.15in
Pe(max)...=60 watts
Zmax.....=8.0 ohms
Re......=4ohms

 

[tesseract]

This will be a very interesting build how ever it comes out, should it happen.

 

[Peter Loeser]

I had considered a tapered horn design but also assumed it would require prohibitively huge enclosures. If I end up wanting to integrate these into my HT, my best bet is behind my screen. My plan is for that space to be roughly 5-6ft from the front wall, about 9 ft tall and 14ft wide. My main LCR speakers will be back there, but nothing else really. Another option, down the road, I'd like to add a pole barn or something along those lines, which could hose a big 2-channel system. Maybe a good candidate for some big subs. My dad will also have a shop, so maybe be build them for his space. I don't anticipate being able to start anything soon, just wondered if the general conensus was about it being a worthwhile endeavor. I appreciate the feedback so far. Who knows, could be a fun project.

 

[Tonto]

Do you have attic space to hold the enclosure. That would free up space behind the screen. Box size is prohibitive other wise. I've seen some nice attic builds. I remember one guy that used a forklift to lift it, then slid it into the attic(took the siding off, then put it back up) over the theater room.

 

[tesseract]

These are very cool retro drivers, but can they do more than midbass duty? How low can these dig?

 

[NBPK402]

It is only rated for 60 watts...is that going to be enough for a bass bin or a sub?

 

[Peter Loeser]

The attic/2nd story will be finished as bedrooms and the HT is in the basement. No extra adjacent space in the basement either.

I don't think anyone is expecting these to match the performance of modern bass drivers. They're a bit of a novelty, so I thought it might be fun to put them to use. I'm leaning toward using these for a garage/outdoor space eventually, since I've been very pleased with my two XS30s for the home theater, and don't really feel a need to replace them.

 

[Tonto]

Looks pretty low with the huge cabinet. That's why I figured a horn design would be better.

 

[chrapladm]

If you had a baffle wall you could seal the wall and add these to the baffle. Not sure if that is enough space but probably very do able. Main thing is to not push these too much so you dont have to repair them.

While others may say they might not compare its what you have and I would use them if I had them.

 

[OJ Bartley]

Peter, these will definitely make a fun project. I'd guess that they will be better suited to midbass than ULF, but I bet you could make some pretty serious MBM's out of them if you have the room. Any pics of the drivers, or are they still stashed away?

 

[Peter Loeser]

No photos at the moment. I'm leaning toward using them in an eventual 2nd garage/shop or trying to integrate them into my patio system. I wonder if I could build enclosures that could be buried in a way that would protect the drivers? We plan to have a poured concrete patio but otherwise i'll have the yard space. That would give me room to use larger boxes. Just a thought. If the age of these drivers makes them more sensitive to moisture I'll likely just plan to use them in the shop.

 

[OJ Bartley]

I just had a vision... if you do manage to get your hands on a second pair of them, you could make a pretty sweet WMTMW speaker that would never fail to impress visually. Use a big 24" horn and a compression driver for the highs and you'd make the biggest offering from DIYSG look tiny by comparison!

Like these "little guys" but even bigger!

 

[Peter Loeser]

I like it! A pair of refrigerator sized speakers. That could definitely be fun!

 

[Silverprout]

Hello,
Send it to me... i will make you a great cabinet !