EVM-12L IR's - Apologies to Red Wirez

[joegold]

http://www.redwirez.com/ir/MesaHalfbackBotEV12L-SM57-Cap-0in.zip

I don't have anything like a K12 here today to check that with, but based on what I'm hearing through my NS10s that sounds *much more* in the ballpark to me.

Actually, I've just gone back and A/B'd some of the SpeakerBox EVM-12L w/SM57 IRs and they're not as far off as what I'm used to as I was alluding to.
When I first got this set of IRs I was really hoping that the TC30 IRs would nail the sound and was quite disappointed when I heard them.

I also think that I probably heard some undesirable stuff when I was checking the SM57 IRs out with the QSC monitors that I can't hear now through my NS10s. But they're definitely not as off-the-mark as I was alluding to.
Sorry 'bout that.

 

[joegold]

Also...
When you guys say "0in", do you have the mic right up on (but not physically touching) the cap?
Or does "0in" mean more like where a grille would be?

I guess what I really want to know here is what the corresponding RW distance measurement would be for a mic placed right on a grille cloth (but not touching it) where the grille sits about 1/4" away from the speaker surround?

I'm guessing it's the 1in or the 2in IRs. Y/N?

If I'm right, then I'm wondering what engineer would ever mic a speaker right at 0in, i.e. right up on the dust cap (or the cone or whatever)?
And it also makes me wonder how using the TC30 at 0in only can hope to capture anything useful about any of these cabinets?

If "0in" means at the grille then just ignore the above.

 

[redwire]

http://www.redwirez.com/ir/MesaHalfbackBotEV12L-SM57-Cap-0in.zip

I don't have anything like a K12 here today to check that with, but based on what I'm hearing through my NS10s that sounds *much more* in the ballpark to me.
Whether it means anything or not, the freq resp as seen in the Axe-IRConverter bears this out.

I'll be very interested in hearing what the TC30 IRs of this cab/driver sound like.
Please take samples from a few more mic positions as well.

Also...
When you guys say "0 in", do you have the mic right up on (but not physically touching) the cap?
Or does "0 in" mean more like where a grille would be?

Just had a "eureka" moment. I hope this will put the "controversy" to rest.

For us, 0" means on the grill or parallel to the baffle for cabs without grill cloth. The point was to mic it like you would in the studio. So, the IRs would sound "right" to people who use these cabs in the studio. So, the 0" measurement isn't actually 0" from the speaker cap and will differ depending on the cab.

Which brings up a critical point. On the Speakerbox cab, the 0" position is probably a little over 3/4" from the dust cap, while the Halfback is closer to 2". I think that may be the biggest contributor to why they don't sound like expected. We should document this better. That we can fix. And we can set the starting point differently on the Speakerbox cab, if it is warranted.

Here's a frequency plot comparing the Speakerbox EVM12L Classic and the Black Shadow EV12L we just did. The nulls in the upper mids even out the further away you pull the mic, which makes sense. They're still some differences. These two positions are not exact analogs, though. The exact same distance lies somewhere in between 1" and 2". There will also be differences attributed to the cab (one is close-backed and the other is open-backed) and to the fact that the speakers are from two different manufacturing eras. The Black Shadow has been well-broken in, while the EVM12L has seen less use, which is probably another factor.

Anyway, when viewed from this perspective, I think everything starts to make more sense.

Yellow is the Speakerbox EVM12L Classic at 2" with an SM57
Orange is the MesaHalfback EV12L at 0" with an SM57

 

[UnsungHeroGuitars]

This puts me in mind of how a PA which has been referenced and tweaked to produce a perfectly flat response doesn't necessarily sound that nice...

 

[Jay Mitchell]

This puts me in mind of how a PA which has been referenced and tweaked to produce a perfectly flat response doesn't necessarily sound that nice...

The fact that the "response" of a sound system as displayed on an RTA screen looks flat is not an indication that the response that matters (direct field) is flat. For that matter, almost nobody here has either the necessary equipment or expertise to accurately measure the "response" of a sound system. To make matters worse, many sound systems - even very expensive ones - are so intrinsically ill-behaved that they cannot possibly be equalized to have "flat response."

All else being equal, the direct field (i.e., no room reflections included) amplitude vs. frequency response of a truly neutral sound system will be flat, with the possible exception of frequencies below ~400 Hz. By itself, flat response in a few listening positions is not sufficient to ensure that a sound system is neutral, but without flat response, the system cannot possibly be neutral. In a neutral system, the sound quality is only a function of the signal that is applied to the input(s). IOW, the sound system contributes no sonic coloration. As a matter of practical reality, the goal of sonic neutrality in a sound reinforcement system is, at best, approximately achieved, and then for only a portion of the audience.

 

[Trem]

really hoping for a bix box 4x12 closed back version of this speaker!

 

[joegold]

http://www.redwirez.com/ir/MesaHalfbackBotEV12L-SM57-Cap-0in.zip

I don't have anything like a K12 here today to check that with, but based on what I'm hearing through my NS10s that sounds *much more* in the ballpark to me.
Whether it means anything or not, the freq resp as seen in the Axe-IRConverter bears this out.

I'll be very interested in hearing what the TC30 IRs of this cab/driver sound like.
Please take samples from a few more mic positions as well.

Also...
When you guys say "0 in", do you have the mic right up on (but not physically touching) the cap?
Or does "0 in" mean more like where a grille would be?

Just had a "eureka" moment. I hope this will put the "controversy" to rest.

For us, 0" means on the grill or parallel to the baffle for cabs without grill cloth. The point was to mic it like you would in the studio. So, the IRs would sound "right" to people who use these cabs in the studio. So, the 0" measurement isn't actually 0" from the speaker cap and will differ depending on the cab.

Which brings up a critical point. On the Speakerbox cab, the 0" position is probably a little over 3/4" from the dust cap, while the Halfback is closer to 2". I think that may be the biggest contributor to why they don't sound like expected. We should document this better. That we can fix. And we can set the starting point differently on the Speakerbox cab, if it is warranted.

Here's a frequency plot comparing the Speakerbox EVM12L Classic and the Black Shadow EV12L we just did. The nulls in the upper mids even out the further away you pull the mic, which makes sense. They're still some differences. These two positions are not exact analogs, though. The exact same distance lies somewhere in between 1" and 2". There will also be differences attributed to the cab (one is close-backed and the other is open-backed) and to the fact that the speakers are from two different manufacturing eras. The Black Shadow has been well-broken in, while the EVM12L has seen less use, which is probably another factor.

Anyway, when viewed from this perspective, I think everything starts to make more sense.

Yellow is the Speakerbox EVM12L Classic at 2" with an SM57
Orange is the MesaHalfback EV12L at 0" with an SM57

That's good stuff to know. Thanks.
Makes me wish that you'd done some Speakerbox TC30 IRs at some distances other than 0in.

 

[Brian G]

All else being equal, the direct field (i.e., no room reflections included) amplitude vs. frequency response of a truly neutral sound system will be flat, with the possible exception of frequencies below ~400 Hz. By itself, flat response in a few listening positions is not sufficient to ensure that a sound system is neutral, but without flat response, the system cannot possibly be neutral. In a neutral system, the sound quality is only a function of the signal that is applied to the input(s). IOW, the sound system contributes no sonic coloration. As a matter of practical reality, the goal of sonic neutrality in a sound reinforcement system is, at best, approximately achieved, and then for only a portion of the audience.

[/quote]

This is irrefutable. But the degree of neutrality you refer to in the last sentence is, relatively speaking, somewhat better than most of the monitoring solutions discussed on this forum, and certainly sufficient for players who seek predictable and well-behaved results from the Axe.

IMO, there is too much time spent discussing the search for the mythical, "ideal" monitor, rather than identifying the best of what is available, and then, if necessary, using the EQ tools available in the Axe to optimize it further.

If you select a monitor (or two), locate it / them appropriately in a room that is suitable acoustically, and then apply reasonable EQ as merited, you have a closed system with predictable behavior. But the moment you transport that monitor or monitors to a different acoustical environment, all bets are off. It's now an open system.

But if you start with the most neutral monitoring system that you can afford / achieve, at least you have a fighting chance.

Rant off. :twisted:

 

[Jay Mitchell]

But the degree of neutrality you refer to in the last sentence is, relatively speaking, somewhat better than most of the monitoring solutions discussed on this forum, and certainly sufficient for players who seek predictable and well-behaved results from the Axe.

It's always worked very well for me. My post was in response to the assertion that "flat response" is not necessarily the ideal. It is the ideal, but you really do have to understand which response needs to be flat.

IMO, there is too much time spent discussing the search for the mythical, "ideal" monitor, rather than identifying the best of what is available, and then, if necessary, using the EQ tools available in the Axe to optimize it further.

Agreed. I've stated many times that there is no magic bullet here. The best a monitor can do is to make your Axe-Fx presets sound exactly like they sound. That is no guarantee that you will like how they sound.

But if you start with the most neutral monitoring system that you can afford / achieve, at least you have a fighting chance.

That's always been my position.

 

[Smilzo]

... "flat response" ... is the ideal, but you really do have to understand which response needs to be flat.

Can you clarify? Very interesting point!

 

[Jay Mitchell]

Can you clarify?

On occasion I give instructional presentations on the subject that can run to several hours in length. In one of these presentations, I can begin to clarify the issues involved, but there is no possibility of doing so here. In an acoustic environment, there are three broad categories of sound: direct, early-reflected, and late-reflected. There are finer distinctions to be made, but these broad ones are a good starting point for understanding. The human ear-brain processes these three types of sound in profoundly different ways. Most measurement techniques (and most people who try to make and interpret measurements) fail to make the necessary distinctions, treating all three categories essentially the same. This can and does lead to all sorts of superstitious conclusions about response that have nothing to do with reality.

 

[Smilzo]

In an acoustic environment, there are three broad categories of sound: direct, early-reflected, and late-reflected. [...] Most measurement techniques (...) fail to make the necessary distinctions, ... and does lead to all sorts of superstitious conclusions about response that have nothing to do with reality.

Now I got it. Not the solution, but at least I got the problem!

I read some of your articles. Keep on rocking, Jay!

 

[vAmp]

... "flat response" ... is the ideal, but you really do have to understand which response needs to be flat.

Can you clarify? Very interesting point!

There is only one real response, and that is that Jay is often flatout right :mrgreen: