Why is mixing cab sizes a bad idea?

[el murdoque]

Respectfully, you are kidding here right? The rest of your post makes good sense to me and seems to agree with my own experience.

Not really.
I just want to get the following point across:
When you mix full range drivers, every single driver will get every frequency and give it's best to do them all.
When you find a 15 inch driver that has a great sound in the lows but is muddy in the higher registers and you find a cab loaded with two tens that cough in a harsh way in the lows, but have a beautiful articulation in the higher registers you simply can not throw these together and pick the advantages.
You need to lowpass the 15 and highpass the tens and make sure the middle does not get way louder than the rest and/or there's no gap between the cabs. Otherwise you will get the tens to cough at the same time your 15 does the warm lows and you get the beautiful articulation of the tens muddied up by the 15.

 

[Chickenwheels]

Not really.
I just want to get the following point across:
When you mix full range drivers, every single driver will get every frequency and give it's best to do them all.
When you find a 15 inch driver that has a great sound in the lows but is muddy in the higher registers and you find a cab loaded with two tens that cough in a harsh way in the lows, but have a beautiful articulation in the higher registers you simply can not throw these together and pick the advantages.
You need to lowpass the 15 and highpass the tens and make sure the middle does not get way louder than the rest and/or there's no gap between the cabs. Otherwise you will get the tens to cough at the same time your 15 does the warm lows and you get the beautiful articulation of the tens muddied up by the 15.

You’d hope you weren’t “finding” these qualities in cabs/speakers, but rather selecting?
I’ve found EVM loaded TL606s sound more beautifully articulate than my old Ampeg or SWR 210 or 410 cabs. A good single driver cab seems more that way to me. Multiple driver cabs just seem to do “louder” better. Just my experience.
There’s no one rule it seems!

 

[Al Kraft]

Not really.
I just want to get the following point across:
When you mix full range drivers, every single driver will get every frequency and give it's best to do them all.
When you find a 15 inch driver that has a great sound in the lows but is muddy in the higher registers and you find a cab loaded with two tens that cough in a harsh way in the lows, but have a beautiful articulation in the higher registers you simply can not throw these together and pick the advantages.
You need to lowpass the 15 and highpass the tens and make sure the middle does not get way louder than the rest and/or there's no gap between the cabs. Otherwise you will get the tens to cough at the same time your 15 does the warm lows and you get the beautiful articulation of the tens muddied up by the 15.

Thanks for taking time to clarify - this seems more consistent with the rest of what you wrote in your earlier post. IME there is no question that when you use multiple full-range cabs, their particular strengths and weaknesses don't automatically blend in a way that solves all problems. There is a good reason multiple driver cabs have crossovers...it ensures that each element producing sound is fed an appropriate signal for its capabilities/characteristics.

 

[agedhorse]

There are choices a designer can make in speaker design that can eliminate many of the negative aspects of combining multiple speakers, even if they aren't identical in size. In fact, done well the results can be better than using identical drivers.

 

[el murdoque]

You’d hope you weren’t “finding” these qualities in cabs/speakers, but rather selecting?
I’ve found EVM loaded TL606s sound more beautifully articulate than my old Ampeg or SWR 210 or 410 cabs. A good single driver cab seems more that way to me. Multiple driver cabs just seem to do “louder” better. Just my experience.
There’s no one rule it seems!

There's one rule: When you add identical cabs, you get more volume and a 'bigger' sound, but more of the same.

When you add speakers that are mismatched, anything can happen. From great to terrible.

Thanks for taking time to clarify - this seems more consistent with the rest of what you wrote in your earlier post. IME there is no question that when you use multiple full-range cabs, their particular strengths and weaknesses don't automatically blend in a way that solves all problems. There is a good reason multiple driver cabs have crossovers...it ensures that each element producing sound is fed an appropriate signal for its capabilities/characteristics.

I was painting a dark picture, using an extreme scenario.
I did so because I often observe that people are under the impression that multiple cabinets (fed from the same outlet) will sit down at a table and discuss their strategies to work as a team.

There are choices a designer can make in speaker design that can eliminate many of the negative aspects of combining multiple speakers, even if they aren't identical in size. In fact, done well the results can be better than using identical drivers.

Hifi and FOH systems have been built like this since forever.....and IMO these are a bit to blame for the old belief that the classical 115+410 stack works so well because the 15 provides the lows while the 10s provide the punch.

 

[chris_b]

There's one rule: When you add identical cabs, you get more volume and a 'bigger' sound, but more of the same.
When you add speakers that are mismatched, anything can happen. From great to terrible.

IME there isn't "one rule". This isn't a black and white situation. Advice to others has to reflect that.

I've owned extremely good sounding rigs containing mixed speakers from Ampeg (210/115), Mesa (210/115) and Bergantino (112/210). You can get run over by a car but that doesn't/shouldn't stop anyone from crossing the road or walking down to the shops. Absolutely be aware of the negatives but don't let them rule your life. Make your judgements based on the positive things.

 

[JonnnyC]

It's probably for a more even sort of sound. Less overlap between speaker sizes and bleed etc etc.

I use a 212 speaker set up. Would probably add a second 212 if I needed it, having said that I'm half convinced most reasons not to mix are 'ideal world' things. The amount of times Ive see a 210 and 115 stack .

At the end of the day, of you like the thought/sound of a mix. Why not?

 

[el murdoque]

IME there isn't "one rule". This isn't a black and white situation. Advice to others has to reflect that.

Yes there is.
As long as you add identical speakers you will get a louder result while the sound stays the same.
You have a head and cab and you want a bit more volume? The surefire way is to get one more of that same cab.

When you start mixing drivers you can yield great results, terrible ones and everything in between.


Being too poor to afford the good stuff while still needing to be quite loud was a situation I've spent several years of my life in. I've played a myriad of combinations of drivers from 8" to 18". With a 2 ohms stable head, I did often run 3 or 4 cabs. My situation "invited" me to try combinations of cabinets that were
a) in the room
b) not currently used by someone else and
c) fair game for me to hook up to my amp

I did play a LOT of stuff that did not work well together. Phase issues, frequencies that were freakishly loud or underrepresented, muddy lows, mids and/or highs, one cab yelling at the threshold of blowing up and another barely putting out sound (4 ohms and 16 ohms don't mix well).
On some occasions the results got better (=louder) when I removed a cabinet (like the obvious 410+410+115 where the removal of the 115 led to a lot more volume).
I've also played a few combinations that looked unlikely to work well at first glance but turned out glorious after some experimenting.

 

[agedhorse]

2 identical cabinets when combined do more than just get louder. The KF extension increases, and the polar pattern changes. There will also be some comb filtering present.

This is true regardless of identical or not identical as the math that governs this does not have anything to do with the size of the speaker.