Weird experience with a Coda II and 2x10

bad_andy · #1 01-08-2009, 01:31 PM

I have a Coda series II amp that was separated into a head and a cabinet by the previous owner Contra-style. The head's been switched between large cabinets on loud gigs and the original Acoustic Image cabinet for practice and small work. So far, so good.

In the last week, I've been borrowing a used Carvin 2x10 Redeye to see how it would sound mated with my Avatar 2x12 for electric bass work. (Quick review: two thumbs up!) Here's where it gets weird: I tried pairing the AC cabinet with the 2x10 to see if I could get the best of both and the volume output is strangely mismatched.

I'm using one each on the two Speakon outputs in the back of the head and the 2x10 gets loud quickly (Master volume at 12 o'clok rolling the channel volume up to 8, 9, 10, 11 o'clock) and the AC cabinet doesn't really pick up much volume until the 2x10 is cranking. I tried a direct A/B comparison with the units plugged in individually at the same gain settings in the amp and it's the same. At 9:00/12:00, the 2x10 is loud enough for an open mic set and the AC is on but fairly quiet. At 12:00/12:00, the 2x10 is really barking but the AC just seems loud enough for practice.

I'm not expecting the AC to have the same bass presence as a full sized cabinet but why would there be such a disparity in volume when the same amp is driving the same wattage at the same load?

bolo · #2 01-08-2009, 01:53 PM

I'm not a techie, but I am gonna guess that's because the Carvin speaker is much more efficient than the AI.

adbass · #3 01-08-2009, 02:32 PM

Cabs with lower impedence will sound louder.

You may also have the cabs out of phase.

tornadobass · #4 01-08-2009, 03:20 PM

They're both 4 ohm cabs, but the Carvin 210 is a fairly efficient cab (I used to do small/medium blues gigs with just one) with a lot of midrange presence. The AI cab, in contrast, is low efficiency with a flat response that neither has a lot of volume nor a lot of presence (I had one of these, too).

The mismatched result you found is entirely expected based on either specs or experience.

In a similar result, I paired a Contra cab with a Wizzy 12 and couldn't really hear the AI. In a different comparison that makes the same point, I compared my GK MB150's internal speaker with the Wizzy cab and got much more volume and high frequencies from the Wizzy.

bolo · #5 01-08-2009, 04:22 PM

Maybe I was right then. Thanks tornader.

If I may, that's not to say inefficiency in a speaker is "bad", like it is with ... a co-worker. I liked the sound of the old Contra I had a lot.

tornadobass · #6 01-08-2009, 04:27 PM

Quote:

Originally Posted by bolo

If I may, that's not to say inefficiency in a speaker is "bad", like it is with ... a co-worker. I liked the sound of the old Contra I had a lot.

A friend once told me that efficiency was inversely related to accurate sound reproduction. That is, inefficient speakers tend to sound more true than more efficient ones. That would seem to be the case between the AI and Carvin cabs.

Where inefficiency becomes bad is when it's the limiting factor in getting the needed volume before the amp begins to distort...or in the example here, where you want to use two cabs for a bigger sound but one is so much quieter that the combination of speakers doesn't accomplish the task that was hoped for.

bad_andy · #7 01-09-2009, 11:52 AM

Thanks, guys. That does make a lot of sense. I'll stick to one at a time for smaller work for now. The AC cab does sound wonderful by itself, I just have to turn it up further to get the warm thump. If I have to crank it past 2-3:00 to be heard above the drums, I'll break out the 2x10 and roll the gain back a bit. Good to have choices.