Mixing speaker sizes

[Wiggybass]

(@ Alex) Yup, for sure, but I can't remember the last time I had the opportunity to put my bass backline in 'free space' at a gig - I wish I could! In practice it's always up against a wall, or a curtain, or whatever, but there's always something behind it whereas there is always plenty of free space in front, which is why I think that rear-ported cabs, in practice, are more reactive to their environment.

I take all your well-made points about speaker parameters. I think the missing link here (and the fundamental difference between PA and backline) is that an instrument amp becomes part of the playing experience, is part of the 'feel' of it, plus the instrument and the amp contribute to the overall noise. In PA-world it's just not like that, for many reasons.

Just out of interest, what is the difference in low-end frequency response between your most and least 'bassy' cabs, regardless of driver diameter? Also, I'm very interested in your comments about dispersion here...

http://barefacedbass.com/technical-information/speaker-size-frequency-response.htm

...as it's not a concept that I've ever encountered in backline before. In PA-world (especially since the widespread adoption of line-source systems) it's still the major buzzword. Are you possibly referring to the frequency-specific acoustic coupling of adjacent drivers, [i]a-la[/i] line-source? Cheers!

[alexclaber]

Wiggy, that's why we only do front-ported speakers, means you can push them right back against the rear wall without a thought, plus you feel the slam of air movement when you're standing very close, which is nice.

Yes, the player interacts with their rig, which is very different to PA usage - and arguably another reason why dispersion matters a lot with backline (even though we're one of the few companies to be focusing on its importance). If you change your playing/EQ to get your tone where you're standing, you want that tone to be heard everywhere else. That change that's happened in the PA world, realising that dispersion matters is one we're trying to pioneer in the MI world (guitar too shortly!)

Our lengthy specs are here: http://barefacedbass.com/uploads/barefaced-cab-specs-jan2011.jpg

The unEQ'd -3dB points for the cabs I was referring to are 71Hz (1x12"), 63Hz (1x15") and 44Hz (1x12"). Obviously you can change the response with EQ but that's the starting point.

[Wiggybass]

Very sensible. I use a pair of Bergantino 1 x 12s which are rear-ported and they're fab but always need an EQ tweak depending on what's behind them.

I can't see any numbers for dispersion in the specs - I'm looking for horizontal x vertical in degrees, did I miss it? I'm intrigued to know how you control this, sad geek that I am!!

[xgsjx]

Working with PA, you'll probably have the luxury of having amps & EQs for each type of speaker (having different ones for subs, mids & so on).
The majority of the bassists on here use one amp to run either one or 2 cabs. Taking away anything else, if you're using 2 different cabs, then you're compromising either one or both as you try to EQ the best sound you can. If both cabs are the same, then they're both going to act fairly similar to any EQing that you need to do.

Sorry I didn't respond earlier, too busy at work after lunch today to post. I think Alex is better at explaining things than me anyway (well, I should hope he is ).

[Wiggybass]

[quote name='xgsjx' timestamp='1349291046' post='1824413']
Working with PA, you'll probably have the luxury of having amps & EQs for each type of speaker (having different ones for subs, mids & so on).
The majority of the bassists on here use one amp to run either one or 2 cabs. Taking away anything else, if you're using 2 different cabs, then you're compromising either one or both as you try to EQ the best sound you can. If both cabs are the same, then they're both going to act fairly similar to any EQing that you need to do.

Sorry I didn't respond earlier, too busy at work after lunch today to post. I think Alex is better at explaining things than me anyway (well, I should hope he is ).
[/quote] That's a perfectly valid point, however, if you have two different configurations of cab from the same maker then one would [i]hope[/i] (note emphasis!) that said manufacturer has tested all possible combinations...!

[peteb]

[color=#222222]I switched from using a SWR 4x10 and a 1x18 to using two matching 4x10s after reading something on here (from Alex I think), which I interpreted as speaker cabs with different size speakers will always be slightly out of phase with each other whereas matching cabs will always have the speakers working together i.e. moving together at the same speed.[/color]
[color=#222222][font="Times New Roman"][size="3"] [/size][/font][/color]
[color=#222222]This seemed to make sense to me and it did seem to sound better (or at least more efficient) but had I understood the reasoning for doing so correctly??[/color]

[Ian Savage]

I have Marshall 4x10 and 1x15 cabs, they sound killer, look amazing and cost me about sixty quid each. Made of win.

[xgsjx]

[quote name='Wiggybass' timestamp='1349294966' post='1824491']
That's a perfectly valid point, however, if you have two different configurations of cab from the same maker then one would [i]hope[/i] (note emphasis!) that said manufacturer has tested all possible combinations...!
[/quote]

I'd like to be able to assume that they would, but as a couple of folk on here have previously pointed out, when it comes to a lot of the larger companies, profit is the main goal & marketing takes priority over technical design. So the designers come up with something great, marketing then says "it needs to look better and what cheaper components can we use, so we can make more profit".

A case of what looks good for rock n roll.

[0175westwood29]

Not to stop ppl discussing this further but whats all the fuss? If you want to mismatch whats it matter. Also arent ppl who put a compact and a midget mismatching?

I know its not only about size after reading through a few threads on this but if having a mismatched rig works for you then i dnt see the big fuss

Andy

(im prepared to get slated for this comment btw)

[alexclaber]

The point I'm always trying to get across when discussing pairing mismatched cabs is related to their differing phase response. The best way to understand of this is to think about the pickups on a Jazz bass. Think of the neck pickup as being a cab with a more bassy sound and the bridge pickup as being another cab with a more trebly sound. The common assumption is that if you pair a bassy cab with a trebly cab you'll end up with a stack that does bass and treble well, whilst getting the mids from both - "best of both worlds".

But what actually happens when you both pickups on full on a Jazz bass (or any other bass with two pickups in parallel)? You don't get the bottom of the neck pickup plus the top of the bridge pickup and the mids being a mix of both. You get the bottom of the neck pickup, the top of the bridge pickup but much less midrange than from either pickup! Why is that happening? It's happening because there are phase differences between the two pickup's output and so instead of all the output summing fully, some of the output sums partially, some of the output cancels partially and some of the output cancels fully. This is a good thing with bass pickups because it gives us a very different third tonal option on a two pickup passive bass.

The same thing happens when stacking dissimilar cabs. Now on the one hand this isn't a problem if the end result is loud enough and sounds right. But on the other hand, the reason someone tends to buy a second cab is because they want to add something in terms of both tone and output to the tone of their existing cab and as the pickup situation illustrates, you won't get that tidy summing - you'll get partial cancellation so the resulting tone will be unpredictable and equally importantly the rig will be less efficient. There's also the matter of mismatched power handling and the cabs' response diverging further at high SPL when things become less linear, so the rig may perform worse and worse as you turn up - exactly when you don't want it to become less efficient!

We designed the Compact and Midget to work together - the two drivers have identical motors and the cab alignments are such that the phase response is very close through the lower frequencies (where it matters - at higher frequencies the path length messes with the phase response whether you have identical cabs or not).

[xgsjx]

You won't get slated for that. No one said mixing drivers doesn't work, it's just the results can be unpredictable whereas adding another of the same cab = more of the same.
Some manufacturers do take the time to design cabs that match up well (Barefaced being among that few), but a lot don't & just make what they think will sell.

Like you said though, if it works for you & you like it, then why not. It's good to know all the pros & cons though.

[xgsjx]

Now that is a good explanation IMO from Alex.
I'm just too slow at typing.

[0175westwood29]

[quote name='alexclaber' timestamp='1349337903' post='1824773']
The point I'm always trying to get across when discussing pairing mismatched cabs is related to their differing phase response. The best way to understand of this is to think about the pickups on a Jazz bass. Think of the neck pickup as being a cab with a more bassy sound and the bridge pickup as being another cab with a more trebly sound. The common assumption is that if you pair a bassy cab with a trebly cab you'll end up with a stack that does bass and treble well, whilst getting the mids from both - "best of both worlds".

But what actually happens when you both pickups on full on a Jazz bass (or any other bass with two pickups in parallel)? You don't get the bottom of the neck pickup plus the top of the bridge pickup and the mids being a mix of both. You get the bottom of the neck pickup, the top of the bridge pickup but much less midrange than from either pickup! Why is that happening? It's happening because there are phase differences between the two pickup's output and so instead of all the output summing fully, some of the output sums partially, some of the output cancels partially and some of the output cancels fully. This is a good thing with bass pickups because it gives us a very different third tonal option on a two pickup passive bass.

The same thing happens when stacking dissimilar cabs. Now on the one hand this isn't a problem if the end result is loud enough and sounds right. But on the other hand, the reason someone tends to buy a second cab is because they want to add something in terms of both tone and output to the tone of their existing cab and as the pickup situation illustrates, you won't get that tidy summing - you'll get partial cancellation so the resulting tone will be unpredictable and equally importantly the rig will be less efficient. There's also the matter of mismatched power handling and the cabs' response diverging further at high SPL when things become less linear, so the rig may perform worse and worse as you turn up - exactly when you don't want it to become less efficient!

We designed the Compact and Midget to work together - the two drivers have identical motors and the cab alignments are such that the phase response is very close through the lower frequencies (where it matters - at higher frequencies the path length messes with the phase response whether you have identical cabs or not).
[/quote]

Well explained, but i do think that some of this makes ppl believe that putting a 410 and 15 together is wrong which is bad, i trust the science but other ppl on here seem to take this science bit far to seriously when ppl ask for advice. As ppl on the forum say one thing but if you go to live show most bands will have a 410/15 setup. So ii can see where newbies get confused, i just think the first and most important bit of advice should be to listen and if you like what u hear then your ok.

Obviously make sure cab ratings are ok but thats easy to do.

Andy

[alexclaber]

In the vast majority of cases, two 4x10"s or two 1x15"s will work better than a 4x10"+1x15" stack. Bear in mind that when you go to big live shows the bass rig is almost incidental - there are big monitors, especially side fills, and a big front of house PA system. With all that acoustic output the 1x15" on the bottom of the stack is usually doing little more than acting as a stand to get the 4x10" up to a more audible height for the bassist.

By all means use a 4x10"+1x15" stack if that's what you own. If you own a 4x10" and want to add another cab, get an identical 4x10". If you own a 1x15" and want to add another cab, get an identical 1x15". If you don't like the tone of your cab, adding another different cab to change the tone of your rig is not a great solution.

[brensabre79]

I think a lot of this info is really useful, but while you're at the cutting edge there will always be large manufacturers a few years behind. The mixing cabs thing is a relatively new realisation to the mainstream I think, as well as other things, so it will take a few years to set in but manufacturers are always changing their product lines.

I used a 4x10 and a 1x15 together for a while, because at the time I got that rig, the 4x10 was a relatively new idea and the 1x15 was pretty standard. I never got the sound I wanted, in the end left the 1x15 at home. I was happy with my 4x10 until recently when I started using a 2x12. Now it seems almost every manufacturer is offering a 2x12, its the new 4x10! And this will change again in the future.

Certain manufacturers also trade off tradition (especially the valve amp making ones), and have configured their speakers to work like the classic rigs of old. You're always going to get this as long as people want to sound like Geddy Lee c.1973 or whoever.

The designers, want to design the cabinet, the marketeers want to make it look sexy, then the accountants come in and ruin both the good looks and smart design because they want to the thing to make a profit (what a crrraaazy idea huh?).

[Wiggybass]

[quote name='alexclaber' timestamp='1349337903' post='1824773']
The point I'm always trying to get across when discussing pairing mismatched cabs is related to their differing phase response. The best way to understand of this is to think about the pickups on a Jazz bass. Think of the neck pickup as being a cab with a more bassy sound and the bridge pickup as being another cab with a more trebly sound. The common assumption is that if you pair a bassy cab with a trebly cab you'll end up with a stack that does bass and treble well, whilst getting the mids from both - "best of both worlds".

But what actually happens when you both pickups on full on a Jazz bass (or any other bass with two pickups in parallel)? You don't get the bottom of the neck pickup plus the top of the bridge pickup and the mids being a mix of both. You get the bottom of the neck pickup, the top of the bridge pickup but much less midrange than from either pickup! Why is that happening? It's happening because there are phase differences between the two pickup's output and so instead of all the output summing fully, some of the output sums partially, some of the output cancels partially and some of the output cancels fully. This is a good thing with bass pickups because it gives us a very different third tonal option on a two pickup passive bass.

The same thing happens when stacking dissimilar cabs. Now on the one hand this isn't a problem if the end result is loud enough and sounds right. But on the other hand, the reason someone tends to buy a second cab is because they want to add something in terms of both tone and output to the tone of their existing cab and as the pickup situation illustrates, you won't get that tidy summing - you'll get partial cancellation so the resulting tone will be unpredictable and equally importantly the rig will be less efficient. There's also the matter of mismatched power handling and the cabs' response diverging further at high SPL when things become less linear, so the rig may perform worse and worse as you turn up - exactly when you don't want it to become less efficient!

We designed the Compact and Midget to work together - the two drivers have identical motors and the cab alignments are such that the phase response is very close through the lower frequencies (where it matters - at higher frequencies the path length messes with the phase response whether you have identical cabs or not).
[/quote] I wondered if you'd be brave enough to start exploring phase response on here ;<)! It's the most misunderstood and opaque area of sound to most people...good luck! In fairness that's an excellent explanation of what actually happens.

Being the pedant I am, I'll add the following additional data:

It's certainly true that the pickups on a twin-pickup instrument cannot be in-phase with each other at all frequencies (because they 'hear' the same string at different points along its length), and the classic sound of a Jazz bass relies on certain frequencies being partially cancelled, but technically they are not 'out of phase' either, because the description of any phase relationship can only describe one frequency at a time. For them to be 'out of phase', with each other i.e. separated by 180deg of phase, we'd have to identify the specific frequency which is affected by the physical distance between them. The half-wavelength of the frequency that corresponds to that distance will suffer the greatest cancellation (though it won't be total silence because of the harmonics and sympathetic resonances created by the structure of the bass. It would work if the bass produced a pure sine wave). [i]So, on a J-Bass we have two independent 'ears', 'hearing' a common source but from different locations.[/i]

This is different to two drivers being driven by the same channel of amplifer. Assuming they are electrically in-phase (i.e. with matching hot / cold wiring), then both drivers will move simultaneously forwards on receipt of positive voltage from the amp. [i]So, in this case, we have two acoustic sources being driven by one signal.[/i]

To the listener, standing in front of said cabs, any phase cancellation could be caused only by a difference in physical alignment in the vertical plane of the two drivers' acoustic centres, as you mention in your description of the Compact and Midget. Using a pair of identical cabs stacked straight would eliminate any phase cancellation because the drivers would be aligned in the vertical plane (which, of course, creates new issues for the same reasons - the frequency whose half-wavelength corresponds to the physical distance between the driver centres will now 'couple', providing in theory up to +6db extra output at that frequency, as happens with my Bergantinos).

Consequently, it's entirely possible that a 1 x 15 beneath a 4 x 10 (even if the front baffles are in vertical alignment) would suffer varying amounts of phase cancellation at specific frequencies, simply because 15" drivers are deeper front-to-back than 10s, thus creating a discrepancy between the acoustic sources of each cab. This might sound good btw. And it might not.

However, just to bring this back to earth a bit, we should also remember that:

1. Most backline amps are frequency-limited, i.e. they are fitted with high and low-pass filters to enhance their efficiency

2. Basses (in fact most instruments) produce a relatively limited range of frequencies, which makes life a lot easier for designers of backline

3. If you follow the rules of minimum impedance then you almost certainly won't damage your amp

4. If it sounds good to you, and nothing's blown up, then it IS good!

Anyway, back to dispersion - I'll understand if it's still a trade secret but I'd love to know more about your thoughts on this because, as I said, it's a new one to me in backline terms.

[Conan]

[quote name='Wiggybass' timestamp='1349346841' post='1824955']
4. If it sounds good to you, and nothing's blown up, then it IS good![/quote]

For most people, this is enough.

However, some of us like the science stuff. A few of us actually understand it (or some of it at least!). Some of us have even made our gear choices on the back of this science stuff. It works for us.

It gets very wearing to be told, in every thread about cabs, that "I used this for years and it sounded good to me". Good for you, but don't question the ears of those of us who have noticed a difference after listening to the advice of the experts.

Thank you all.

[Wiggybass]

[quote name='Conan' timestamp='1349354810' post='1825176']
For most people, this is enough.

However, some of us like the science stuff. A few of us actually understand it (or some of it at least!). Some of us have even made our gear choices on the back of this science stuff. It works for us.

It gets very wearing to be told, in every thread about cabs, that "I used this for years and it sounded good to me". Good for you, but don't question the ears of those of us who have noticed a difference after listening to the advice of the experts.

Thank you all.
[/quote] Well said sir!

[alexclaber]

More later but there's more to out of phase than being 180 degrees out of phase (equivalent to reverse polarity). Any amount of phase difference will affect summing!

[alexclaber]

Yes, re-reading your post Wiggy, you seem to have polarity and phase confused! Phase is continuously variable and all loudspeakers have varying phase response across their bandwidth because they are reactive electrical components (i.e. volts and amps do not move in simple synchrony).

[Big_Stu]

[Wiggybass]

[quote name='alexclaber' timestamp='1349357800' post='1825239']
Yes, re-reading your post Wiggy, you seem to have polarity and phase confused! Phase is continuously variable and all loudspeakers have varying phase response across their bandwidth because they are reactive electrical components (i.e. volts and amps do not move in simple synchrony).
[/quote] Polarity describes an exclusively electrical relationship. Phase offset (expressed in degrees) is usually used in audio to describe whether two signals are phase-synchronous ('in phase') or whether and by how much they are asynchronous ('out of phase'). Any device that produces more than one frequency will exhibit varying phase response because phase measurements are frequency-specific.

[Wiggybass]

[quote name='alexclaber' timestamp='1349357409' post='1825226'] More later but there's more to out of phase than being 180 degrees out of phase (equivalent to reverse polarity). Any amount of phase difference will affect summing! [/quote] Of course! Here's a good explanation which goes beyond sinusoidal phase comparisions:

http://www.sengpielaudio.com/calculator-timedelayphase.htm

Edited October 4, 2012 by Wiggybass

[stevie]

[quote name='peteb' timestamp='1349295813' post='1824504']
[color=#222222]I switched from using a SWR 4x10 and a 1x18 to using two matching 4x10s after reading something on here (from Alex I think), which I interpreted as speaker cabs with different size speakers will always be slightly out of phase with each other whereas matching cabs will always have the speakers working together i.e. moving together at the same speed.[/color]

[color=#222222]This seemed to make sense to me and it did seem to sound better (or at least more efficient) but had I understood the reasoning for doing so correctly??[/color]
[/quote]
I'm afraid not. The only reason to change your 18 would have been to increase power handling (although even this is a bit moot). Otherwise, a 1 x 18 will work with a 4 x10 as well as another 4 x 10 – in many cases better, in fact, because 18s don't normally have an extended HF response and are thus less likely to cancel the mids/highs coming from your 4 x 10.

[Mr. Foxen]

Also missed that impedance varies with frequency as well as phase, and fairly sure that can make fun with mismatched cabs too, picturing a ported cab with the big impedance peak at a frequency where the paired cab is not sensitive, resulting in more power going to the less sensitive cab at that frequency.