why do amp specs never show what is lowest note they can perform?

[ThisBass]

On the other hand, the 50mm drivers in my headphones produce 40 Hz just fine.

ported or sealed headphone?
I'm kidding, sorry couldn't resist.

 

[Downunderwonder]

Does anyone really care that doesn't do PA for large theaters and arenas?

8 pages of caring, and counting.

 

[JimmyM]

8 pages of caring, and counting.

8 pages of one or two people caring and counting, with the rest pointing out exactly why more companies don't do it.

 

[DukeLeJeune]

The original question had to do with amp [or cab?] specs showing the lowest note they can perform. That's actually what I've tried to indicate in my somewhat unorthodox way of presenting specs - I quote how far down the cab is at the first overtone of whatever its lowest useful note is. So if low-B is the target, then I say how far down the cab is at 62 Hz (the first overtone of low-B). But I really don't know whether that's more useful than quoting the -3 dB, -6 dB, and/or -10 dB figures. Maybe I should post those too, so people can make a more apples-to-apples comparison with other manufacturers who use those figures.

One principle to keep in mind is, there is a trade-off relationship between low end extension, efficiency, and box size. So if you have two approximately equal-sized and otherwise generally similar cabs from different manufacturers, and one has much higher efficiency and much deeper extension "on paper", consider the possibility that the difference arises more from marketing than from engineering.

Real-world power handling (both thermal and mechanical, or excursion-limited) is probably more likely to be a place where significant differences exist between otherwise outwardly similar cabs, and the characteristics that contribute to high real-world power handling often show up as a higher real-world price. So the cheap cab rated at 2,000 watts may well have less real-world power handling and SPL capability than the more expensive cab that's rated at "only" 400 watts.

Since not everyone measures with the same yardsticks, imo you can make valid comparisons based on specs within a given manufacturer's product line, but making comparisons between different manufacturers can be less reliable.

None of this really tells you how a cab sounds, which would actually take a great deal of data plus a few lessons in psychoacoustics, and even that wouldn't tell you as much as hearing the cab. A great deal of the effort a cab designer puts into his work may not be reflected in the specs.

 

[RedJag]

OP Has to come clean. She's trying to reproduce the brown note.

 

[DigitalMan]

OP Has to come clean. He's trying to reproduce the brown note.

OP - he?

 

[RedJag]

OP - he?

lol -5 points for reading comprehension

 

[agedhorse]

8 pages of one or two people caring and counting, with the rest pointing out exactly why more companies don't do it.

Yes, I care a lot from the pro audio perspective, but that's as an engineer who has to determine with at least some accuracy the performance of the PA versus what is being requested and needed. In order to provide an additional ~3dB of SPL, almost double the PA is required, so this stuff is important if you want to make any money.

But, most folks (even many PA folks) don't care nor do they want to expend the considerable effort to care and I understand this too.

 

[Linnin]

A great deal of the effort a cab designer puts into his work may not be reflected in the specs.

Hello?! Do I hear reality calling?

 

[DigitalMan]

Yes, I care a lot from the pro audio perspective, but that's as an engineer who has to determine with at least some accuracy the performance of the PA versus what is being requested and needed. In order to provide an additional ~3dB of SPL, almost double the PA is required, so this stuff is important if you want to make any money.

But, most folks (even many PA folks) don't care nor do they want to expend the considerable effort to care and I understand this too.

I see a lot of large, expensive, and highly technical solutions that are ultimately "engineered" by the purchase order.

 

[BadExample]

they think they want them to, but really they don't, then when they don't they think they do and are fully satisfied.

I had to go out back, smoke myself a J, come back and reread that. Makes perfect sense now brotha

I am referring to single speaker amps. Arrangements are a whole other subject.

Amps don't have speakers.

Guys! Where are our manners?? I’ll go first: @StringGirl welcome to TalkBass. It’s nice to have a lady join our hackneyed ranks! Please consider filling out your profile as the information is helpful in our efforts to help you.

Knock it off Sir Paul, she's already involved with some dude named Roland.

But most just want to screw around, eat, gossip and party.

Amen!

But in an era of crazy and often groundless litigation, most companies have learned that the less you say about anything, the better off you are.

WARNING: Do not use as a ladder. May cause hearing damage. Contains asbestos, know to cause cancer by someone in California. Do not burn, then concentrate and inhale fumes. Do not eat.

These days I try very hard to limit myself to algebra, trig and the concepts of integrals/derivatives.

I'm becoming more and more inclined to only use my brain to turn wood into sawdust and metal into chips, unless I'm getting paid to think. Even then, I try to limit it to one task per day.

Andy, BTW: I think I was at my current job just a few weeks when I was told I can't call my lab users "lab rats." Luckily, before the conversation ended, a lab rat came into the room to ask questions or get help. So, I asked her, "How many lab rats are in your group?" She looked up wiggling fingers and thinking for a moment and came back with, "Five, plus a dish washer."

OP: Look at my forum name and disregard my comments. I am just the obligatory forum heckler.

 

[-Asdfgh-]

One principle to keep in mind is, there is a trade-off relationship between low end extension, efficiency, and box size. So if you have two approximately equal-sized and otherwise generally similar cabs from different manufacturers, and one has much higher efficiency and much deeper extension "on paper", consider the possibility that the difference arises more from marketing than from engineering.

I was looking at some speaker cabinet specs and was curious about the maximum SPL quoted as doing the standard calculation forward from the raw speaker sensitivity and RMS power handling resulted in a much lower figure (up to 6dB) which I could see being made up for by port output. I also see active PA speakers with maximum SPL quoted that is much higher than the passive equivalent which uses the same enclosure and speakers. So I'm presuming marketing.

 

[Munjibunga]

... Maybe I should post those too, so people can make a more apples-to-apples comparison with other manufacturers who use those figures. ...

Now, which kind of apples? Yours may be Golden Delicious while others may be Granny Smith or Fuji.

 

[ReedyBass]

I think this thread may be running out of steam. It's already -10dB in posting level at P9. We've lost interest in the fundamental and we're onto the second harmonic.

 

[alaskaleftybass]

I had to go out back, smoke myself a J, come back and reread that. Makes perfect sense now brotha



Amps don't have speakers.



Knock it off Sir Paul, she's already involved with some dude named Roland.



Amen!



WARNING: Do not use as a ladder. May cause hearing damage. Contains asbestos, know to cause cancer by someone in California. Do not burn, then concentrate and inhale fumes. Do not eat.



I'm becoming more and more inclined to only use my brain to turn wood into sawdust and metal into chips, unless I'm getting paid to think. Even then, I try to limit it to one task per day.

Andy, BTW: I think I was at my current job just a few weeks when I was told I can't call my lab users "lab rats." Luckily, before the conversation ended, a lab rat came into the room to ask questions or get help. So, I asked her, "How many lab rats are in your group?" She looked up wiggling fingers and thinking for a moment and came back with, "Five, plus a dish washer."

OP: Look at my forum name and disregard my comments. I am just the obligatory forum heckler.

Hey @BadExample how's it going? Woke up this morning and couldn't find my teeth.

I've looked everywhere. Guess it's oatmeal for me!

 

[alaskaleftybass]

"even that wouldn't tell you as much as hearing the cab."

 

[DukeLeJeune]

I was looking at some speaker cabinet specs and was curious about the maximum SPL quoted as doing the standard calculation forward from the raw speaker sensitivity and RMS power handling resulted in a much lower figure (up to 6dB) which I could see being made up for by port output. I also see active PA speakers with maximum SPL quoted that is much higher than the passive equivalent which uses the same enclosure and speakers. So I'm presuming marketing.

The theoretical 6 dB advantage of a sealed box over a vented box (assuming the same woofers) happens only at the box tuning frequency. The boost extends north of the tuning frequency somewhat, but it does not extend up into the midband.

If you have noticed that vented boxes are generally more efficient than comparable sealed boxes, the primary reason is, woofers whose parameters work well in a vented box tend to have higher efficiency than woofers whose parameters work well in a sealed box.

"Max SPL" figures can have quite a bit marketing/optimism in them! They are probably based on "peak power", which is usually twice "music program power", which in turn is usually twice "RMS or AES" power (the latter standing for Audio Engineering Society), and that could be where the 6 dB discrepancy comes from. And optimistic max SPL figures typically ignore the effects of thermal compression, which is another topic.

Another possible source of SPL optimism is, a peak somewhere in the frequency response. For instance, I make a bass cab that has a deliberate +6 dB peak (which can be smoothed out via a switch). If I had a really well-paid marketing department, it might have been a 104 dB cab instead of a 98 dB cab. Alas, I do not have a well-paid marketing department.

 

[BadExample]

Hey @BadExample how's it going? Woke up this morning and couldn't find my teeth.

I've looked everywhere. Guess it's oatmeal for me!

View attachment 1078317

Not so bad now, sir. Just over a horrid Type A Flue that is not covered by the regular flue shots. Regular shot covers three strains. You have to be an endangered species to get the forth covered, and it's out there now. Doc makes his staff mask and gown up for anyone with as much as a cold.

Now, which kind of apples? Yours may be Golden Delicious while others may be Granny Smith or Fuji.

That's not even counting the lovely, juicy, crunchy, sweat, GMO out of season apples and grapples. Peavey white papers lead me to believe that at best the specs will help you decide on which amp is best within one company. I do like to see a good set of specs myself, for whatever reason.

Alas, I do not have a well-paid marketing department.

You'll have to learn to lie on your own, Duke. Guilt fades with time... You can also do the very fine print thing, like 1MWRMS*

*@0.5Hz, max. 0.001nSec, once per lifetime of the speaker, which we've already done for you.

 

[Al Kraft]

There's a rason they require doctiors ro

I see a lot of large, expensive, and highly technical solutions that are ultimately "engineered" by the purchase order.

+1...and that's frequently not a good thing IME. Specifying desired performance in the intended operating environment allows an opportunity for innovation and clever solutions that may be more cost effective. Many people tend to confuse "their requirements" for "equipment specifications"...it's a subtle, but very significant difference.

 

[alaskaleftybass]

You'll have to learn to lie on your own, Duke. Guilt fades with time... You can also do the very fine print thing, like 1MWRMS*