Schroeder Cabinets ... smart design = very compact ! (regular and lights)

[alexclaber]

I've been thinking about this for a while now and concluded that dB@1W1m is a rather unrepresentative measurement.

If one were to carry out a frequency analysis of a cab, sweeping from 20-20,000Hz, measuring the voltage across and current drawn by the cab, and constantly adjusting the gain on the power amp to keep the resulting power drawn at 1W, one would end up with a true plot of dB@1W1m but which would have no relevance to the real world sound of the cab.

The only way to measure the response of a cab is to deliver it with a constant voltage sweep from 20-20,000Hz, as a power amp set with a certain gain is a fixed voltage amplifer (and will merely amplify the current to match the impedance presented by the cab).

However, that won't take account of the fact that at certain frequencies, the cab will demand more power due to the impedance varying across the frequency spectrum. For instance at the tuning frequency of the cab, the impedance peak will massively reduce the power drawn, hence the efficiency in dB@1W1m will be much much greater whilst the efficiency in [email protected] will be more realistic.

In an ideal world I'd like to see plots of:

1. Sensitivity in [email protected] against frequency (to give an indication of the cab's sound)
2. Sensitivity in dB@1W1m (to give an idea of the demands on amp to achieve this response)
3. (Lessening importance) peak power (i.e. excursion) vs frequency
4. Maximum continuous spl vs frequency (a combination of power handling, sensitivity/watt and peak excursion (@ v low frequencies))

But I suspect our boutique builders have better things to do with their time and money!

Alex

 

[Nightbass]

This isn't a trick. It's actually a more honest way of rating speaker sensitivity. Using an output voltage instead of power levels things out so you can make legitimate comparisons between cabs with different impedances and it's more analagous to the real world. Say, if you were comparing cabs, one at 8 Ohms, one at 4. You'd typically keep the amp settings the same, right? But, in order to have the same amount of 'power' dissipated you'd need to turn the amp up for the 8 Ohm box. So assuming the amp settings remain the same, if the sensitivity of the cabs is based on 1W/1m, that could cause a bit of a problem. If both boxes had identical 1W/1m senitivities, with the amp at the same settings the 4Ohm box would be 3dB louder than the 8 Ohm one, by virtue of it receiving more power.
So what you'd hear wouldn't match the specs.
This is another instance where the 'industry standard' isn't necessarily the best way to do it.

More manufacturers should do this.

It took me a while but I finally see what you are saying. If you compare a bunch of Bergy cabs, both 4 and 8 ohm versions, without changing your amp, those 2.83V specs will agree with what your ears tell you. So without having to worry about impedances, you can tell on paper that the 322 is going to be louder than the 210, without having to take power into consideration.

That's great, esp. if you're only comparing Bergs with Bergs, but since everyone else is using 1 watt, you do have to take impedance into consideration.

I sent an email to Jim B. asking about this, and will let you know what he says. Perhaps there is method in this madness.

On a side note, I personally do not see a big deal between a 4 or 8 ohm cab. That 3dB difference is barely noticeable. After trying out dozens of cabs, I no longer care if they are 4 or 8 ohms. I simply make sure my power amp is big enough to deliver enough power to whatever the load is. Even if I'm using a head, I don't really care about that 3dB that I'd get from a 4 ohm cab. And in the case of 1x12's and 1x15's, you
don't have that option anyway. If you're not loud enough with your 8 ohm cab, you need a bigger amp, or add another speaker!

The bottom line, though, is that we do need all manufacturers to consistently use the industry standards for measurements, and to start providing complete (not partial) specifications.

Cheers,
Nightbass

 

[klorence]

found this little chart online.

(Invalid Link Removed)


nightbass -

you make a very nice summary of all that's been discussed - well put!

i just wanted to say, 3db is not that much volume difference (i believe 1db represents the smallest "perceivable" change in volume), but it does become a factor when you consider your power amp requirement doubles to raise your percieved volume by that amount.

there are so many issues and factors involved, it becomes mind-numbing after awhile. bottom line - choose the cab with impedance that takes full advantage of your amp and is loud enough for your situation and sounds the best to you!

 

[ddayseb]

Hey all,

I am, to be totally honest, an instrumental and tonal novice compared to a lot of folks, but I do live about 1/2 an hour from Jorg, and I've been really curious about his cabinets since he told me he was planning to make them a few months ago. I'm going to try to get over to his demo studio either today or tomorrow (this weekend at the worst!), so at least one more concrete experience with the 410 and 21012 will be thrown in here within the next few days. For those interested, I'll be testing the cabs with my L-2500 and ABM 500, and I'll compare it to my EBS 311 and Ashdown 410 (and maybe some of Jorg's own stuff if he wants so we can get a broader scope on the differences between the 3 boxes).

Best,
Seb

 

[Mark Reccord]

found this little chart online.

(Invalid Link Removed)


nightbass -

you make a very nice summary of all that's been discussed - well put!

i just wanted to say, 3db is not that much volume difference (i believe 1db represents the smallest "perceivable" change in volume), but it does become a factor when you consider your power amp requirement doubles to raise your percieved volume by that amount.

there are so many issues and factors involved, it becomes mind-numbing after awhile. bottom line - choose the cab with impedance that takes full advantage of your amp and is loud enough for your situation and sounds the best to you!

That's a good graphic but they're a bit out of whack on the 'perceived volume' thing. It's generally agreed in the industry that 10dB represents doubling/halving of perceived volume, not 6 dB.

 

[klorence]

i sit corrected.

 

[Nick man]

This isn't a trick. It's actually a more honest way of rating speaker sensitivity. Using an output voltage instead of power levels things out so you can make legitimate comparisons between cabs with different impedances and it's more analagous to the real world. Say, if you were comparing cabs, one at 8 Ohms, one at 4. You'd typically keep the amp settings the same, right? But, in order to have the same amount of 'power' dissipated you'd need to turn the amp up for the 8 Ohm box. So assuming the amp settings remain the same, if the sensitivity of the cabs is based on 1W/1m, that could cause a bit of a problem. If both boxes had identical 1W/1m senitivities, with the amp at the same settings the 4Ohm box would be 3dB louder than the 8 Ohm one, by virtue of it receiving more power.
So what you'd hear wouldn't match the specs.
This is another instance where the 'industry standard' isn't necessarily the best way to do it.

More manufacturers should do this.

Who honestly would say its a fair comparison to test a 4 ohm version of one cab and the 8 ohm version of another?

As long as a fair comparison is done (two cabs of same impedance) the specs should befine to go off of.

The point is that Bergantino cabs (SWR uses similar techniques last i checked) look better to someone who isnt aware of all this science we're talking about here. The general public should be given easy to compare stats that are similar across the board.

1w/1m has become the standard so I think it should be used.

 

[Petebass]

Say, if you were comparing cabs, one at 8 Ohms, one at 4. You'd typically keep the amp settings the same, right? But, in order to have the same amount of 'power' dissipated you'd need to turn the amp up for the 8 Ohm box. .

Mark I see what you're saying but I don't fully agree. By testing the 4 ohm cab, you would have adjusted the amp output until it was putting out 1 watt. Switching to an 8 ohm cab and leaving the settings the same would mean the amp is now pushing less than 1 watt. So you'd have to turn the amp up regardless of which method you use.

 

[Mark Reccord]

Mark I see what you're saying but I don't fully agree. By testing the 4 ohm cab, you would have adjusted the amp output until it was putting out 1 watt. Switching to an 8 ohm cab and leaving the settings the same would mean the amp is now pushing less than 1 watt. So you'd have to turn the amp up regardless of which method you use.

Well, yes and no and maybe..... If you wanted a true comparison of how the speakers behave with everything else held constant, you wouldn't turn the amp up.
Using the amp's output voltage gives a more accurate version of what's actually going on because it holds everything constant except the speaker. This is why Berg and companies like Meyer Sound use that convention. It's certainly not dishonest.

Again, the 1W/1m thing is the standard, but it doesn't really tell the whole story, especially when you consider the impedance of a speaker is frequency-dependent. Say a nominally 4 Ohm speaker is tested for sensitivity at 1k, where the impedance might be 2.5 Ohms (for example... I'm not basing this on any particular driver). The 1W rating at that frequency is going to require less voltage at the amp's outputs than it would at (say) 100Hz where the impedance might be 6 Ohms. Of course this opens up the whole can of worms about manufacturers quoting sensitivity numbers at single frequencies selected to put a positive spin on the product......

That said, I don't consider specs all that important when looking at cabinets and I certainly wouldn't buy a 4 Ohm cab simply because it would allow my amp to produce more power .... Well if we're talking about my amp, it wouldn't give me more power, but I digress....

 

[Petebass]

Well, yes and no and maybe..... If you wanted a true comparison of how the speakers behave with everything else held constant, you wouldn't turn the amp up.

......but if you don't turn up the amp, it's not 1 Watt anymore, so you creating your own basic flaw in the 1w/1m testing process aren't you?

But i agree with the impedance thing, except that a 4 ohm speaker won't be 2.5 ohms at 1k. Is shouldn't drop below 4 which is kinda the whole point of the 4 ohm "Nominal" impedance rating.

Another flaw of the 1w system s that they use 1k regardless of the size and type of the driver. Take for example a 15" car sub woofer. It may not have anything to say at 1k given the speakers natural inductance, resulting in a very low sensitivity rating. Or it may have a nasty resonance at that frequency giving it an artificially high one. Either way the speaker wasn't designed to be reproducing 1k in normal use, so why test it at that frequency?

So the industry standard system isn't perfect. But rather than using several different testing methods and creating confusion, aren't we all better off sticking with one system educating ourselves to the limitations?

 

[Rezdog]

Greetings from the North,
I'm amazed by all the tech specs and testing methods being bantered about. Gentlemens..., specs & stats may be black and white but the truth is in the grey. It all comes down to what YOU hear. Numbers and logic can be used as a guide,but they certainly don't give you all the answers. Trust in your own humanoid ears. After all, you are musicians.
Rezdog

 

[Ericman197]

Greetings from the North,
I'm amazed by all the tech specs and testing methods being bantered about. Gentlemens..., specs & stats may be black and white but the truth is in the grey. It all comes down to what YOU hear. Numbers and logic can be used as a guide,but they certainly don't give you all the answers. Trust in your own humanoid ears. After all, you are musicians.
Rezdog

You too say gentlemens? Excellent.

 

[Petebass]

You too say gentlemens? Excellent.

I though he was talking to my dad for a second there

 

[Nick man]

Greetings from the North,
I'm amazed by all the tech specs and testing methods being bantered about. Gentlemens..., specs & stats may be black and white but the truth is in the grey. It all comes down to what YOU hear. Numbers and logic can be used as a guide,but they certainly don't give you all the answers. Trust in your own humanoid ears. After all, you are musicians.
Rezdog

Excellent suggestion except for one thing...

3 of the guys asking for stats wont see one of these till they buy one.

An Australian, Canadian and a Floridian arent going to get to hear one and decide, so we do the next best thing.

 

[oddio]

......but if you don't turn up the amp, it's not 1 Watt anymore

Interesting debate Pete and Mark... and if one was listening to that 1w/1m let's not forget the effect of the Fletcher-Munson curve. Those are the levels where the effect would be more pronounced, correct? It seems that you would need to compensate as Pete suggests if there is any listening involved.

Edit: Not to oversimplify, but isn't this one of the reasons why the whole 1w/1m practice became standard? Unfortunately any measurements taken at 1KHz produce numbers that aren't really meaningful to the bassplaying community. Perhaps we need to draft our own standards?

 

[Mark Reccord]

......but if you don't turn up the amp, it's not 1 Watt anymore, so you creating your own basic flaw in the 1w/1m testing process aren't you?

But i agree with the impedance thing, except that a 4 ohm speaker won't be 2.5 ohms at 1k. Is shouldn't drop below 4 which is kinda the whole point of the 4 ohm "Nominal" impedance rating.

Quickly:

But if you have to turn up to get 1W with an 8 Ohm box, you wouldn't have the same output voltage out of the amp. Which means the amp isn't operating the same for each cab. Using the voltage measurement avoids this. At any rate, both systems have advantages and drawbacks. Personally, I like the voltage one.

Ever looked at impedance curves for drivers? Lots of them do go plenty below their nominal impedance. The 'nominal' thing is sort of an average.

 

[Nick man]

Well if you have frequency response graphs and an efficiency rating with a stated frequency (1kHz or otherwise) you should be able to make a better judgement of efficiency across the board.

It also helps to compare the overall tone of different cabs.

 

[ddayseb]

So, I finally went down to Jorg's house yesterday and tried out the 21012 and the 410. In short, I think they're flapping great and I'll be posting my two cabs up for sale shortly to fund a 21012.
As to my opinion of these cabs, I'd stress that I am a youngin and a novice, and that I have not played a lot of the high end cabs out there to which people are comparing these cabs. Nonetheless, it's my experience that Jorg's cabs are:

A) Built like vaults. This is the first thing I noticed. It was apparent upon inspection that these things are built so burly that they will not even bother sneering at whatever road thrashing you may try to subject them to. They are also a good bit smaller than the website pictures had lead me to imagine them, making their circa 75 lbs. (74 for the 21012 and 78 for the 410) a bit more workable for the able backed, and easily carted and trunked for the rest of us. Neodymium speakers would (-will? Ah dunno-) be ludicrously great.

B) Sonically very consistent, clean, punchy, articulate, flexible, and allowing of the tone of my other equipment. Even though both cabs I tried had distinct personalities, the 21012 with a more open, deeper, slightly darker sound, and the 410 with more of a focused, Ampeg-y growl, both cabs could do whatever I wanted them to with EQ tweaking; it appears to just be a question of where you want your starting point to be. My amp and bass are growly and aggressive as heck already, so I went for the 21012 to leave more room for diffrent sounds. The real seller for me was that it sounded near perfect with my Ashdown's EQ and voicing circuits cut. Because of my limited experience, I can't speak to the Schroeders' loudness in an industry-wide context, but both the cabs I tried were substantively louder than my Ashdown 410 (granted, it runs at 8 ohms vs. Jorg's 4). I actually never even brought my EBS inside because it was apparent upon first listening that Jorg's boxes were just as clean, while being louder, more coherent (i.e. it didn't feel like chunks of the sound were cut out to make it sound like something besides a physical instrument was being played), fuller, more flexible, and without the harshness and brittleness that made me move on from the EBS in the first place.

C) Totally even and consistent all the way down to B (actually the 21012 will keep going down to A, which we didn't try with the 410). I know nothing of the sonic physics of which many people here speak, but I perceived absolutely no change in performance all the way down to the big four one.

D) Like other people have said, oddly still clear and articulate from almost any angle besides directly behind it, and from substantive distance. Even EQ-ed to be dubby and inflated, the sound never got muddy, even as Jorg played 16th notes while I walked around the outside of his studio. The swamp monster that is outdoor gigs dissipates into the dirt! (A bit dramatic, I know. Sorry. English major and all.)

Phew. So there you have it. I like them a lot, if you can't tell. Go try them out if you want; people are right to say that Jorg's super nice and a straight shooter.

seb

 

[Ericman197]

So, I finally went down to Jorg's house yesterday and tried out the 21012 and the 410. In short, I think they're flapping great and I'll be posting my two cabs up for sale shortly to fund a 21012.
As to my opinion of these cabs, I'd stress that I am a youngin and a novice, and that I have not played a lot of the high end cabs out there to which people are comparing these cabs. Nonetheless, it's my experience that Jorg's cabs are:

A) Built like vaults. This is the first thing I noticed. It was apparent upon inspection that these things are built so burly that they will not even bother sneering at whatever road thrashing you may try to subject them to. They are also a good bit smaller than the website pictures had lead me to imagine them, making their circa 75 lbs. (74 for the 21012 and 78 for the 410) a bit more workable for the able backed, and easily carted and trunked for the rest of us. Neodymium speakers would (-will? Ah dunno-) be ludicrously great.

B) Sonically very consistent, clean, punchy, articulate, flexible, and allowing of the tone of my other equipment. Even though both cabs I tried had distinct personalities, the 21012 with a more open, deeper, slightly darker sound, and the 410 with more of a focused, Ampeg-y growl, both cabs could do whatever I wanted them to with EQ tweaking; it appears to just be a question of where you want your starting point to be. My amp and bass are growly and aggressive as heck already, so I went for the 21012 to leave more room for diffrent sounds. The real seller for me was that it sounded near perfect with my Ashdown's EQ and voicing circuits cut. Because of my limited experience, I can't speak to the Schroeders' loudness in an industry-wide context, but both the cabs I tried were substantively louder than my Ashdown 410 (granted, it runs at 8 ohms vs. Jorg's 4). I actually never even brought my EBS inside because it was apparent upon first listening that Jorg's boxes were just as clean, while being louder, more coherent (i.e. it didn't feel like chunks of the sound were cut out to make it sound like something besides a physical instrument was being played), fuller, more flexible, and without the harshness and brittleness that made me move on from the EBS in the first place.

C) Totally even and consistent all the way down to B (actually the 21012 will keep going down to A, which we didn't try with the 410). I know nothing of the sonic physics of which many people here speak, but I perceived absolutely no change in performance all the way down to the big four one.

D) Like other people have said, oddly still clear and articulate from almost any angle besides directly behind it, and from substantive distance. Even EQ-ed to be dubby and inflated, the sound never got muddy, even as Jorg played 16th notes while I walked around the outside of his studio. The swamp monster that is outdoor gigs dissipates into the dirt! (A bit dramatic, I know. Sorry. English major and all.)

Phew. So there you have it. I like them a lot, if you can't tell. Go try them out if you want; people are right to say that Jorg's super nice and a straight shooter.

seb

Do you know what he has in stock right now? I've been told that the cabs I wanted ( 2 8 ohm 1210's ) wouldn't be able to be built until around September. I have a burning desire to own one of these cabs, and I'll go for the 410 or 21012 if I have to. I'd rather have small and light cabs, but I can handle 70'ish pounders.

 

[Petebass]

Quickly:

Ever looked at impedance curves for drivers? Lots of them do go plenty below their nominal impedance. The 'nominal' thing is sort of an average.

I've got some in front of me now. Seems you're right, it can go lower but by no more than 75% or so, and very rarely lower than Re.

But if you have to turn up to get 1W with an 8 Ohm box, you wouldn't have the same output voltage out of the amp. Which means the amp isn't operating the same for each cab.

But if the wattage drops when we connect the 8 ohm speaker, didn't the voltage drop at the same time? In which case, aren't we by turning it up simply bringing the voltage back to where it was when we had the 4 ohm speaker attached. The way I see it is the amp isn't operating the same unless you adjust the output, and that problem is common to both methods?