Mixed cabs, double dog dare me

[ThisBass]

Except when the designs themselves support doing so in verifiable, science and measurement based ways.

So true but, I can't remember "verifiability" had ever been a subject on generic "rainbow press" discussions

 

[ThisBass]

OP asked a question IF the "forbidden" mixing matters in his living room.
For solo playing in a living room he might chose the sound he likes best just to feel happy.
On stage he should take a sound just to stay well in the mix. Personally I prefere kinda somewhat different sound at home for "solo" versus playing with my band mates.

 

[BadExample]

OP asked a question IF the "forbidden" mixing matters in his living room.
For solo playing in a living room he might chose the sound he likes best just to feel happy.
On stage he should take a sound just to stay well in the mix. Personally I prefere kinda somewhat different sound at home for "solo" versus playing with my band mates.

"forbidden"? Please refer to the 11th commandment.

 

[ThisBass]

So, it's not really a mixing driver sizes thing; it's a mixing different cabs thing.

Right

The issue revolves around phase response at low frequencies,

Most of the time this of no concerne cause most often phase difference is way too small to cause issues

as well as excursion limts.

this issue may happen but, it also might happen that the more powered driver actually does less excusrsion then the less powered driver

You could have wildly different sized drivers (a110 cab and a 215, for example), and have them work fine together. On the other hand, you could have two different 112's, and have issues with cancellation at low frequencies, or blowing one driver due to mechanical overexcursion.

Regarding power handling I'm not sure that anybody ever tried to mix HiFi cabs with pro MI/Audio cabs.
And again phase cancellation is not a proper tool to explain sound issues except for mixing ported cabs with sealed cab at some content

There's no simple rule -

As I told

to accurately predict success or failure, you have to have some speaker design chops.

knowing one or two things about cab design

 

[Signalsdrone]

Different sizes and manufacturers. I even put the 10's on the bottom, THE HORROR!

 

[Linnin]

New Bass cab from Eich

View attachment 2774583 View attachment 2774584

Ah-Ha! The anti-mixed driver Gestapo must suck molasses.

 

[Linnin]

Different sizes and manufacturers. I even put the 10's on the bottom, THE HORROR!

That's the proper way to do it!

 

[ThisBass]

Growing old I forgot OP's question

 

[BadExample]

Growing old I forgot OP's question

I think it was something like, "What is the most common TB fight topic?"

 

[BadExample]

That's the proper way to do it!

Even with mid scooped Fender strings? Bwahaha joking friend

 

[fdeck]

Mixed driver sizes can in fact sound as good OR BETTER than identical sized drivers IF they are designed to work that way from the start, if they conform to the necessary math and physics models of the acoustic system.

I think people may be talking about two different things:

1. Multi-way systems, such as woofer / tweeter, or woofer / midrange / tweeter, where the drivers operate in different frequency spaces. Those systems typically have a crossover.

2. "Mixing drivers," where different sized drivers are operating in substantially the same frequency space.

The Mesa speakers that I looked up all seem to be in the former category.

 

[Old Garage-Bander]

I think one big confusion that comes along with mixing discussion derives from marketing department goals as well as endorsers aim to earn money. Whenever any marketing department advertises the mixing of 15s with 10s or any endorser is seen with a mixing rig then there is discussion on TB that the endorser might be payed money to play mixed stuff. The marketing department goals seem to be pretty obvious just to make best profit.
TB is full of this discussions. I think we do pretty much disservice science every time when we try to make endorsers as well as marketing departments responsible for the existing of mixed rigs within a cab family.

IMO/IME science wise it makes absolutely no sense just to frequently assume (discuss) they should have known way better because of "well known" issues coming along with mixing stuff.

Sometimes with those multiple cabs you see on a stage, not all of them are hooked up. Just promotional eye candy.

 

[agedhorse]

I think people may be talking about two different things:

1. Multi-way systems, such as woofer / tweeter, or woofer / midrange / tweeter, where the drivers operate in different frequency spaces. Those systems typically have a crossover.

2. "Mixing drivers," where different sized drivers are operating in substantially the same frequency space.

The Mesa speakers that I looked up all seem to be in the former category.

I was talking about the mixing of different sizes drivers (or cabinets with different sized drivers) operating over the same frequency range.

If designed properly, there is nothing wrong with it AND it may open up some performance options that may not be possible out of a single driver.

Kind of reminds me of the comments by old time upright players saying that solid body basses and amplification could NEVER work (during the tube only era), or later players saying that solid state amps would NEVER work, or class D amps would NEVER work, or NEO speakers would "NEVER" or that 5/6/7 string would NEVER work.

EVERY one of the above has in fact proved the "NEVERS" to be wrong.

 

[fdeck]

I was talking about the mixing of different sizes drivers (or cabinets with different sized drivers) operating over the same frequency range.

If designed properly, there is nothing wrong with it AND it may open up some performance options that may not be possible out of a single driver.

Kind of reminds me of the comments by old time upright players saying that solid body basses and amplification could NEVER work (during the tube only era), or later players saying that solid state amps would NEVER work, or class D amps would NEVER work, or NEO speakers would "NEVER" or that 5/6/7 string would NEVER work.

EVERY one of the above has in fact proved the "NEVERS" to be wrong.

Thanks for clarifying. And I agree with what you say about the "NEVERS." For one thing, those predictions are rarely based on solid science and math. Rare exceptions tend to be quite narrowly defined, for instance the trisection of the angle, or the insolubility of the quintic.

In the case of music gear, what "works" is subjective, and I think we actually have a very wide tolerance range. An old boss of mine once said: "Everything works a little."

On the other hand, I've been in situations where a design was going to be subjected to well defined performance tests, and I took one look and said: "This thing won't work, and can't work." In some cases it was because the proposed idea violated the laws of physics. In others, it was because I anticipated that the effort required to make it work would not materialize in the available time. In the latter case, it was partly a matter of ethics to help someone avoid months of wasted effort or making a promise to a customer that couldn't be met.

But letting someone try mixing cabinets doesn't rise to that level of risk. And if they feel that it sounds good, and doesn't blow up, then it works.

 

[agedhorse]

When the theory says it will work, the math model says it will work, the measurements of the physical model agrees with the math model, that's pretty good validation that the theory is solid.

This isn't about wild ass seat of the pants design.

 

[fdeck]

When the theory says it will work, the math model says it will work, the measurements of the physical model agrees with the math model, that's pretty good validation that the theory is solid.

This isn't about wild ass seat of the pants design.

Absolutely. I hope I wasn't suggesting otherwise. Your designs have certainly spoken for themselves, and will continue to do so.

 

[ThisBass]

I think any ported MI cab (series) design (should) begin with its essential characeristica of 4th order filter theory.
Butterworth alignment may sound too "dull" for MI application while Tchebbycheff alignment may sound too loosen due to noticeable riddle at step response.
Another consideration that also (should) be taken into account is the negative feedback loop of MI amplifiers. For MI amplifiers its not unusual to have "moderate" control to the driver just to improve "musical" feel of the device. No that's not a bug its a feature.
Cab filter coefficients alignment about the range of Linkwitz Riley alignment might provide a good ballpark to get a good (MI) balance of tightness and musical "smooth" feel for the bass player.

This considerations are totally free off from any driver size considerations. A given family of drivers may provide drivers of 10" and 12" and 15" diameter. For this (given) driver family Fs and mids response may be conversely proportinal to driver diameter. For same cab Filter Coefficients so it was possible to build 10" loaded and 12" loaded and 15" loaded cabs. Each cab would "perfectly" match to one of the others cause Filter alignment would match to any cab within this cab family. The 15" loaded cab would provide the best low end extension while the 10" loaded cabs would provide the best "punch" due to extended mids top range. While the 12" loaded cabs where considered as good allrounders.

As the cabs would (naturally) provide different low end extensions it was very "natural" to have some deviation for the phase response at the lowish frequency range. This devation was of no concerne, cause Filter coefficients for the different cabs would perfectly match.
The amplifer could perfectly "control" any combination of the different cabs cause step response of any cab would perfectly match to any of the other ones.

The sitiation for an amplifier was totally different for different cabs coming with different filter (coefficients) alignment.
The step response for quasi Butterworth alignment looks way dfferent from Tchebbycheff alignment.
So for two 15" loaded cabs with same cab tuning and very "similar" phase response it would happen that the back EMF of the two drivers do send totally different "informations" back to the amplifier about the "amount" of regulation (voltage) quantity.
The amplifier would have no more chance to control both drivers just the same way. To the contrary one of the drivers would miss some control while the second one was "damped" too mauch. Furthermore there was also uncontroled interaction between two drivers cause the amplifier could control only kinda "average" at best.

I do think may be smewhere in the very past someone might have noticed that cabs that do not match soundwise also do show some difference in phase response and, as its so easy to "understand" that some difference of phase response does cause "cancellation" just declared any kind of phase deviation as root of all evil.

 

[ThisBass]

Meant as supplement to the "science" considerations above.
Some folks may think that different cabs which are carefully designed to work well together may show "matching" phase response just to avoid issues. Any different cab with different f3 will naturally show different phase response at the lows. Its not possible to design different cabs that show different f3 for "matching" phase reponse. IF phase response was just the same for two cabs THEN also the cabs was just the same!

edit (something off topic),
we are used to discuss lots of phase stuff, then Xmax and the amount of moved air volume considerations and of course SPL at 1Watt but, we rarely to never discuss what kind of cab alignment (cab design filter coefficients) does sound best "musical" to our needs as bass players.

 

[agedhorse]

Meant as supplement to the "science" considerations above.
Some folks may think that different cabs which are carefully designed to work well together may show "matching" phase response just to avoid issues. Any different cab with different f3 will naturally show different phase response at the lows. Its not possible to design diffrent cabs that show diffrent f3 for "matching" phase reponse. IF phase response was just the same for two cabs THEN also the cabs was just the same!

edit (something off topic),
we are used to discuss lots of phase stuff, then Xmax and the amount of moved air volume considerations and of course SPL at 1Watt but, we rarely to never discuss what kind of cab alignment (cab design filter coefficients) does sound best "musical" to our needs as bass players.

I have been careful to qualify my comments by stating that the LF phase response characteristics are designed so that they work together without causing undue problems. They don't have to be "exactly the same", but they need to be close enough (sensitivity, q, slope and F3 combined in some part with group delay) to avoid the problems that plague some combinations that do not work well together. This is where the art and science begin to blur, as different combinations of the above parameters may also bring desirable flavors to some players depending on their goals.

 

[oZZma]

How can I say if there is a phase cancellation issue with a cabs pairing? Is that something you can hear clearly?