Ampeg Isovent Cabs

[hayseed]

Any users? I may pick one up this week in a trade for a 1998 MIM Pbass i own.  I have never seen one up close before but i always wondered what those pointy-front Ampegs were all about. The 15 configuration is designed so crazy with the whole "push/pull" thing happening. Anyway if anybody uses one, let know what you think. Thanks

[Hemisaurus]

It's an isobarik folded horn, with 2 10"s mounted in the horn space.

See that big 18 EV cab of mine, it's kinda like that, except it's got a 15" driver mounted either side, mounted against each other and wired out of phase. Make sure they are wired out of phase or you are in trouble, when one pushes, the other pulls. In a horn, a speaker is acting more like a piston pushing air, than a transducer, isobarik is kind of like a V-Twin one piston assisting the other. Mounting speakers against each other like this improves a lot of their performance characteristics, and allows fairly mediocre drivers to perform exceptionally well.

Caveats

• Like I said the 2 15"s must be wired out of phase, when one goes in the other must go out, else they would be pushing and pulling against each other and tear each other apart
• The 15"s must be identical, they must have the same frequency responses etc. or else it won't work right and again you'll get them tearing each other apart. So just throwing in 2 similar 200W 15"s or whatever won't work, they must be the same make/model or otherwise made to be indentical

This cab performs best when run bi-amped, though you can use it's full-range mode, if I had one amp I would just hook it to the 15"s and forget about the 10"s it's the room filling, chest constricting, bass you want to hear.

Yeah it's a horn, I'm excited about it

[Hemisaurus]

Actually I take it back, it may not be a horn, it may be an isobarik bandpass, either way the same rules apply, I'm just not quite as excited

[grimniggzy]

never heard one but I saw an ad for one a little while ago.
def look like they bring the ruckus.

[Danny G]

Yes.

They are the most bang for the buck size-wise that you will find. And you can bi-amp them, which offers mre flexibility than a typical cab. Use the top 10's for small rooms, use just the bottom 15's if you need to use your guitar amp as a bass amp.

They rock, loved mine til I blew the speakers, then took it to a repair place which fucked it all up. So I still own mine, tho out of commission. Would love to get it back up and running when I have the cash.

Again. YES.