General Question about impedence

[Gatts]

hello, first post.

im looking into building a 1x15 bass cab to go along with my 2x10 and Ampeg SVT3, im leaning toward the TL606 i think its called.

My problem is that my 2x10 has a 4 ohm impedence, which means hooking up another 4 ohm, or even 8 ohm is going to leave the impedence at 2 or 2.66 which are both going to ruin my amplifier. even if i get the second cabinet at 16 ohms, the two together will make 3.4 or something like that which is still too low.

My question: is there some way i can hook the speakers up in a different way to make a minimum of 4 ohms total with the three speakers? I might consider taking the bottom off my 2x10 and fuzing it with the 1x15 that i'll build inorder to make one "cabinet" instead of having two.

Thanks a lot, if this has been answered, a link to the thread would be awesome

[Chuck H]

Open up your 2X10 and rewire it for 16 ohms (assuming it's two 8 ohm speakers). Or better yet, wire up a 4/16 ohm switch and mount it on the cabinet.

Then build your 1X15 at 8 ohms for a total ohm load of 5.3 with both cabs plugged in. This way you can still use either cab seperately too.

Or build a crossover so you can build the 1X15 at 4 ohms and leave the 2X10 at 4 ohms. You will maximize watts this way and improve speaker performance.

Chuck

[cbarrow7625]

I agree with Chuck. Also, don't open up the 2 x 10 and fuse it with the 1 x 15 to make one cabinet. Each driver(s) will be happier in their own enclosure with like speakers (i.e., the 2 x 10 is fine). The box volume and porting parameters of the 10's and 15 are not likely to be similar, therefore they require different enclosures for the best performance.

[Gatts]

Originally Posted by Chuck H

Open up your 2X10 and rewire it for 16 ohms (assuming it's two 8 ohm speakers). Or better yet, wire up a 4/16 ohm switch and mount it on the cabinet.

Then build your 1X15 at 8 ohms for a total ohm load of 5.3 with both cabs plugged in. This way you can still use either cab seperately too.

Or build a crossover so you can build the 1X15 at 4 ohms and leave the 2X10 at 4 ohms. You will maximize watts this way and improve speaker performance.

Chuck

I think i'll be doing the first option, rewiring the two 8 ohm 10" speakers in series to make 16 ohms and then getting an 8 ohm 15" speaker to get 5.3 ohms.

Awesome responce Chuck thanks a lot

[Chuck H]

Cool. Glad I could help. There are some other considerations...

With the 2x10 at 16 ohms and the 15 at 8 ohms you will be putting most of your watts into the 15. If this seems OK then there's no other problem with this arrangement.

If you really want to hear the 10's balanced with the 15 you have four options I can think of.

1) buy two more 10's at 4 or 16 ohms and wire the 2x10 for 8 ohms.

2) build a crossover and use a 4 ohm 15, as mentioned earlier.

3) buy another complete 2X10 cabinet, wire it for 16 ohms also and run it parallel to the other 2X10 cabinet with a Y splitter. So you'd have 1X15 and 4X10's

4) use a 16 ohm 15 for a total ohm load of 8. This won't give you as many watts as a 4 ohm (or 5.3 ohm) load though.

Just FYI

Chuck

[pontiacpete]

Chuck,
would you mind explaining to me or pointing me to place that explains how a crossover is built?
pete

[Chuck H]

Originally Posted by pontiacpete

would you mind explaining to me or pointing me to place that explains how a crossover is built? pete

Actually... Yes.

No offence intended, but this is definitely one of those subjects that can be be found with a few Google searches. I know because I have done it myself. Asking me to spoon feed the info to you assumes that your time is more valuable than mine.

I couldn't possibly remember all (or any of) the sites I've seen on the subject. Many relate to car audio, but who cares. Watts are watts.

A crossover is simply a device that employs inductors and capacitors to direct certain frequencies to certain speakers. The fact that you post here is indicative that you could probably figure it out from there. Good search text would be:

"crossover design" (in quotes as shown)
crossover inductor capacitor
crossover schematic (both with and without quotes)
crossover calculator (this is a good one once you've learned some basics)

Good luck and have fun.

Chuck

[pontiacpete]

You're right Chuck, I should have just looked it up on my own first, before posting that question. Sorry to have bother you.

Regards
pete