mixing speakers

[Paul_C]

If you have (as I'm planning at the moment) two 8 ohm cabs, one a 1x12 250w, the other a 1x15 300w and you're running them from a single amp which is 500w @ 4ohms, will one cab dominate the other, or are they reasonably closely matched ?

I remember using a 300w EBS cab with a 400w Accugroove into the same amp, and it sounded like the EBS cab was the more obvious of the two, though that might just have been the characteristics if the two cabs, rather than their relative wattage capacity.

[bass_ferret]

There is no answer to that - it depends on the sensitivity and frequency response of each cab and also which cab gets stacked on top nearer your ears.

[Paul_C]

[quote name='bass_ferret' post='156960' date='Mar 13 2008, 07:47 PM']There is no answer to that - it depends on the sensitivity and frequency response of each cab and also which cab gets stacked on top nearer your ears.[/quote]

I did wonder if the stacking was part of the issue, the EBS being the one on top.

I shall suck it and see then !

The speakers I plan to use are almost identical in sensitivity - 99.9 and 99.2 and frequency range claimed is identical - 54Hz-3.7kHz

[Bill Fitzmaurice]

[quote name='Paul_C' post='156949' date='Mar 13 2008, 02:32 PM']If you have (as I'm planning at the moment) two 8 ohm cabs, one a 1x12 250w, the other a 1x15 300w and you're running them from a single amp which is 500w @ 4ohms, will one cab dominate the other, or are they reasonably closely matched ?[/quote]What's more to the point is whether their responses will complement or detract from each other. The majority of the time the latter is the case. One of the first things you learn in How to Design Loudspeakers 101 is never to mix different drivers or cabs covering the same bandwidth. Yes, I know, that's how it's always been done with bass cabs, but that doesn't make it any less wrong. My advise: don't do that.

Edited March 13, 2008 by Bill Fitzmaurice

[bass_ferret]

[quote name='Bill Fitzmaurice' post='157012' date='Mar 13 2008, 08:58 PM']What's more to the point is whether their responses will complement or detract from each other. The majority of the time the latter is the case. One of the first things you learn in How to Design Loudspeakers 101 is never to mix different drivers or cabs covering the same bandwidth. Yes, I know, that's how it's always been done with bass cabs, but that doesn't make it any less wrong. My advise: don't do that.[/quote]
I remember you keep saying that Bill but can never remember why. Remind me.

[Paul_C]

[quote name='Bill Fitzmaurice' post='157012' date='Mar 13 2008, 08:58 PM']What's more to the point is whether their responses will complement or detract from each other. The majority of the time the latter is the case. One of the first things you learn in How to Design Loudspeakers 101 is never to mix different drivers or cabs covering the same bandwidth. Yes, I know, that's how it's always been done with bass cabs, but that doesn't make it any less wrong. My advise: don't do that.[/quote]

Well the cabs in question are your OmniTop designs, with Eminence Deltalite IIs in.

I was hoping to make life easy for myself by having the option to use the 1x15 on its own in rehearsals or at smaller gigs, and both for gigs with drummers.

I have just signed up to your forum to ask there, but you're welcome to harangue me here instead

To help (hopefully) clarify my reasons, I'll copy a reply to another question elsewhere:


[quote]The amp - a Markbass LMKII, is 500W into 4ohms, 300W into 8ohms.

The speakers I plan to use, Eminence Deltalites, are 12" 8ohm 250W and 15" 8ohm 300W.

I don't like to use a cab of less wattage than the amp, so I wouldn't want to use the 12" on its own if only using one cab, but the 15" would be fine. Two 12s together would be ok, but then I'd have to use both all the time.

Two 1x15s is bigger than I'd like, I'm trying to keep things as compact as possible.

The OmniTops are simple to build (simpler than the Omni10s for sure).

Two cabs rather than one are easier to carry and easier to load if space is limited.[/quote]

Obviously if my plan is a foolish one, it'd be easier to know now, before I start spending money

[Bill Fitzmaurice]

[quote name='bass_ferret' post='157025' date='Mar 13 2008, 05:13 PM']I remember you keep saying that Bill but can never remember why. Remind me.[/quote]Because the responses of the two cabs are different, and the result is akin to adding oil and water. If you want to use a fifteen to get maximum low end that's fine, and if you want to run a smaller driver to get better mids and high that's fine too. But the smaller driver shouldn't be a twelve or ten, it should be an eight or a six, and a crossover should be employed so that only the lows go to the 15, and only the mids and highs to the smaller driver. That's how it's been done in high-fidelity, theatrical and PA applications since circa 1927. Perhaps the electric bass cab industry will wake up and smell the coffee by 2027. Perhaps not.

[Paul_C]

My Accugroove had a 12", a 6" and a couple of tweeters in it, so it does happen.

I shall have to decide to either make two 12s, or an OmniTop 2x12, or two 15s/OmniTop 2x15 by the looks of things.

The Omni12 Tallboy would have been nice, but it'd never fit in the car

[bass_ferret]

Your Accugroove had a crossover.