The Myth Lives On!! (Underpowering)

[ThisBass]

Originally Posted by two fingers

That's why I said ALMOST always. And the Walkabout and Streamer aren't exactly ONE tube now are they? But there are a great many amps with a single 12AX7 stuck in them for the purpose of calling it a "hybrid" only. I owned the Eden and a couple of SWR's and have a Shuttle 6.0 now. I also own the Walkabout and some old tube heads. I am also currently in school for electronics. While I don't know everything yet I am perfectly capable of using both a schematic and my ears to determine whether or not a tube is useful or marketing dribble. And quite often from a tone standpoint and an electronic one the tube does virtually nothing and was put there just so they could point it out in an ad. You could straight wire the socket (using no tube at all) and get almost same results.

But thanks for your input.

Sorry to derail.

One 12AX7 tube in a preamp can do a lot of tube sounding purpose, or even nothing.
It all depends on the schematic the tube is working in.

If the tube has "nothing to work" the sound is very equal/similar to the solid state.

There are some vintage tube amps out there with only one tube for the preamp stage.
There is no doubt about it that these preamps sound like tube preamps.

IMO tube sound quality of any tube preamp depends never on the amount of numbers of preamp tubes.

Some tube preamp sounding is muddy even with three preamp tubes (or even more of them).

It is the designers aim how much "tube sound" one tube shall give to the sound.
It can be a lot of it, but even nothing of it.

[KJung]

Originally Posted by Tractorr

It is not so egregious an offense that I wouldn't buy from GK.

I suppose more than anything I dread walking into a Guitarcenter and having one of their brain dead associates adamantly tell me that the GK has a digital power amplifier, because that is what it says in the marketing literature.

THAT would be a different discussion that I could give you a total +1 on

[Bob Lee (QSC)]

Originally Posted by KJung

Again, 'digital' as a short hand description for class D/SMPS amps, has been used for decades, and is pretty well understood as representing 'small and lightweight' (primarily in the power supply) versus 'bigger and heavier'.

The problem with using misplaced and inaccurate terminology, even if it involves a long-entrenched misnomer, is that many who try to dig deeper, to understand better, to learn--they're troubleshooting, or trying to be an informed buyer, or just wanting to use their gear optimally--often take the terminology at face value. And that ends up hampering their learning and understanding of the concepts. It leads them astray in their exploration.

Audio is already full of poorly chosen--and therefore poorly understood--terminology, phrases, etc., and it leads to a great deal of misunderstanding, misdiagnosis, bad system design, and added time and expense.

[Passinwind]

Originally Posted by Bob Lee (QSC)

Audio is already full of poorly chosen--and therefore poorly understood--terminology, phrases, etc., and it leads to a great deal of misunderstanding, misdiagnosis, bad system design, and added time and expense.

+ a million Bob.

[Tractorr]

Originally Posted by Bob Lee (QSC)

The problem with using misplaced and inaccurate terminology, even if it involves a long-entrenched misnomer, is that many who try to dig deeper, to understand better, to learn--they're troubleshooting, or trying to be an informed buyer, or just wanting to use their gear optimally--often take the terminology at face value. And that ends up hampering their learning and understanding of the concepts. It leads them astray in their exploration.

Audio is already full of poorly chosen--and therefore poorly understood--terminology, phrases, etc., and it leads to a great deal of misunderstanding, misdiagnosis, bad system design, and added time and expense.

Thank you Bob.

You have set me straight on some issues before and I think this is an important view.

Why perpetuate a confusing term?

Something from the earlier conversation that I should have made clear. I think that "digital" amp is not used to sound superior to an analog amp. I think digital is used to sound superior to Class D. To an uniformed consumer who has seen market hype about Class A designs (even though I know there are few if any Class A bass amps), Class D sounds like a step down.

[walterw]

Originally Posted by walterw

if the lower-rated amp gets the signal loud enough for the job without any clipping, then that amp is fine no matter how much lower it is.

the only "rule" i can see is "an amp rated just a little below the speaker (or higher) should not be driven into hard, continuous clip, because it will create too much power for too long, cooking the speaker."

Originally Posted by KJung

Your rule is not really correct. The 'rated power of a speaker' means nothing regarding this issue, and that is incorrect. The rated power of a speaker is based on the thermal limits of a driver. The only way to do harm regarding that spec is to apply too much absolute power, and the vast majority of cabs will let you know there is a problem by farting out or compressing LONG before you damage a woofer.

OK, you're talking about mechanical overexcursion, right? which usually means driving the speaker below the box tuning.

i was just thinking of the "thermal" part, that the danger is just when an amp clean-rated a little below gets pushed into hard clip, whereupon it puts out well above.

anyway, agreed, a player with half a brain should be able to notice the speakers not sounding good well before you get to this level of danger.

[aborgman]

Originally Posted by KJung

Again, the big question is 'so what'. Do you think, for some reason, some marketing genius is sitting in a dark back room saying 'yeah, if we call this 'digital' the kids will buy it.

Absolutely.

See: "Digital Ready" cassette tapes, cables, headphones, etc.

If you think it ISN'T marketing deciding to call it digital - who is?

If marketing is deciding to call it digital, but it isn't intended to increase sales - why would marketing do it?

[Tractorr]

Originally Posted by aborgman

Absolutely.

See: "Digital Ready" cassette tapes, cables, headphones, etc.

If you think it ISN'T marketing deciding to call it digital - who is?

If marketing is deciding to call it digital, but it isn't intended to increase sales - why would marketing do it?

They are not called digital cassettes though are they?

No, because that would then be a DAT which is a different technology.

The modifier "Ready" is what makes it marketing speak and not a misnomer.

[KJung]

Originally Posted by aborgman

Absolutely.

See: "Digital Ready" cassette tapes, cables, headphones, etc.

If you think it ISN'T marketing deciding to call it digital - who is?

If marketing is deciding to call it digital, but it isn't intended to increase sales - why would marketing do it?

Nice easy way to separate their 'heavy line' from their light line. Again, I have never seen anything from any bass amp company saying, 'buy this amp because digital is better'.

Silly, trivial issue.

I agree, 30 years ago when CD's came out, that was a very different thing and everyone was piling on. This has nothing in common with that 30 years later.

[KJung]

Originally Posted by Tractorr

They are not called digital cassettes though are they?

No, because that would then be a DAT which is a different technology.

The modifier "Ready" is what makes it marketing speak and not a misnomer.

In addition, back them, the typical schmo had no idea what the CD thing was all about. That was, in a way, a nice way to say 'all this old stuff will work with all this new stuff'.

[aborgman]

Originally Posted by KJung

Nice easy way to separate their 'heavy line' from their light line. Again, I have never seen anything from any bass amp company saying, 'but this amp because digital is better'.

Right - you see a bass amp company saying, "but this amp is better because it's lighter because it's digital"

Originally Posted by KJung

I agree, 30 years ago when CD's came out, that was a very different thing and everyone was piling on. This has nothing in common with that 30 years later.

Yes, it does.

The reasoning behind choosing to misuse the term (and it IS a misuse, and they KNOW it's a misuse) is/was an attempt to increase sales - both now and then.

[KJung]

Originally Posted by Bob Lee (QSC)

The problem with using misplaced and inaccurate terminology, even if it involves a long-entrenched misnomer, is that many who try to dig deeper, to understand better, to learn--they're troubleshooting, or trying to be an informed buyer, or just wanting to use their gear optimally--often take the terminology at face value. And that ends up hampering their learning and understanding of the concepts. It leads them astray in their exploration.

Audio is already full of poorly chosen--and therefore poorly understood--terminology, phrases, etc., and it leads to a great deal of misunderstanding, misdiagnosis, bad system design, and added time and expense.

While I agree, it is very easy to get 'non marking info' on most products, especially bass amps.

[KJung]

Originally Posted by aborgman

Right - you see a bass amp company saying, "but this amp is better because it's lighter because it's digital"




Yes, it does.

The reasoning behind choosing to misuse the term (and it IS a misuse, and they KNOW it's a misuse) is/was an attempt to increase sales - both now and then.

Completely, utterly disagree. So be it. Again, topic isn't even worth discussing. I'm out

The cool thing is, you can easily take care of this issue by voting with your wallet!

[Tractorr]

Originally Posted by KJung

While I agree, it is very easy to get 'non marking info' on most products, especially bass amps.

So in other words, "buyer beware."

This attitude is exactly why I don't like seeing GK do this. They are a stand up company that builds great gear. They don't need to use this language that has any chance of being misconstrued.

Class D, Lightweight, Micro are all acceptable. Why chose the one that has other connotations in the audio world?

They think it will sell more amps.

[CL400Peavey]

I work in a regulatory group, and we spend most of our days telling marketing what they cant say about a product. They actually dont care to know what is going to far. In their minds none of its a mis-use.

[ThisBass]

Originally Posted by walterw

OK, you're talking about mechanical overexcursion, right? which usually means driving the speaker below the box tuning.

i was just thinking of the "thermal" part, that the danger is just when an amp clean-rated a little below gets pushed into hard clip, whereupon it puts out well above.

anyway, agreed, a player with half a brain should be able to notice the speakers not sounding good well before you get to this level of danger.

That's only one of many assumptions that are poorly understood.

For most folks there is only a difference between:
it is audible clean,
it is audible hard clipped.

But starting from electrical clean operation that is electrical narrow to hard clipping, up to short time well audible hard clipping effects there is a very very wide range of additional power (power increment).

I have no idea where to boundary all the practical situations of real live.

But electrical clean power is very very very different (very less) to audible clean power.

Originally Posted by walterw

OK, you're talking about mechanical overexcursion, right? which usually means driving the speaker below the box tuning.

The frequency spectrum of a bass guitar is a very complex story.
Spectrum varies vers. time duration.
Attack sounds different to swinging note.
Not all of the produced frequencies are audible, some transients are subharmonics for a very short time duration.

In general it is not meaningful to translate all the rated amp power into speaker excursion below the F3 tuning of a cab.

But there are extreme situations possible, depending on the users choice of playing technique and sound settings, then it is possible to translate full power to subharmonics.

But every player is different, and that tells that it is NOT possible to do any predictions to all of us.

edit
post #7
Boss ODB-3 and farting speaker

[agedhorse]

IMO, this does not apply well to bass speaker systems. Free air is about as far as it gets from bass reflex and sealed speaker systems. Free air mechanical power response just has little relation to how a speaker performs and how much power it can handle in a practical cabinet. Also, a 2 hour survival test doesn't accurately reflect the typical bass speaker consumer's application. Most players expect more out of a bass speaker IME.

Originally Posted by ThisBass

AES2-1984 (r2003)

4.5 Power-Handling

4.5.1 Test Conditions and Equipment.
The lf driver shall be mounted in free air so that the direction of motion of the diaphragm is in a horizontal
plane and so that there is no appreciable air loading from adjacent structures. The driver shall be excited with a
band of pink noise extending one decade upward from the manufacturer’s stated lf limit of the device. The
noise shall be bandpass filtered at 12dB per octave with Butterworth filter reponse characteristics, and the peakto-
rms voltage ratio of the noise signal supplied to the lf driver shall be 2:1 (6 dB). Refer to Appendix C for
recommended method. The manufacturer shall state the upper and lower cutoff frequencies (– 3 dB) of the
noise signal.

NOTE: The committee adopted this free-air power-handling test only after many hours of intense deliberation.
We recognize that such a test will not always produce results that reflect the intended use of the loudspeaker.
However, the free-air test is more practical than an “infinite battle” (5VAS) test. It avoids the issue of which
enclosure to use and has the same net effect on diaphragm excursions on an infinite baffle. The free-air test
requires a dramatically smaller test facility, produces much lower sound-pressure levels, and is easily
duplicated, with simple test equipment and in the field. This test method allows similar loudspeakers from
different manufacturers to be compared on an equal basis.

4.5.2 Test Procedure.
The device under test shall be subjected to successively higher powers and allowed to reach thermal equilibrium
at each increment (approximately 2 h). Power shall be determined as the square of applied rms voltage, as
measured with a “true rms” voltmeter, divided by Zmin. The rated power of the device shall be that power the
device can withstand for 2 h without permanent change in acoustical, mechanical, or electrical characteristics
greater than 10%.

[ThisBass]

Originally Posted by agedhorse

IMO, this does not apply well to bass speaker systems. Free air is about as far as it gets from bass reflex and sealed speaker systems. Free air mechanical power response just has little relation to how a speaker performs and how much power it can handle in a practical cabinet. Also, a 2 hour survival test doesn't accurately reflect the typical bass speaker consumer's application. Most players expect more out of a bass speaker IME.

IMO that is a very valid point.

However it is often done so by many manufacturers.

A well known manufacturer states the following:
" Multiple units exceed published rating evaluated under EIA 426A noise source and test standard while in a free-air, nontemperature-controlled environment."


I remember on a 410 cab of famous German manufacturer rating the handling to 800 Watt RMS.
But some users noticed a obvious high cone excursions...


Some years ago I asked a custom cab designer how he rates the cab power handlings.

The answer was very simple:
"...if I rate too high I have got fear some users may destroy the drivers, ...if rate too low I have got fear the cab remains unmarketed.


Another prof designer I talked to stated the situation a bit different:
"...there should be two different specs stated by manufacturer, one rating for the lows, a second rating for low mids and above ..."


Never the less it's often seen that manufacturer translate the free air driver measurements 1:1 into power handling of cabs.

Sometimes it is indeed with some lower ratings then free air results, but most of the time these cab ratings are very similar to the driver ratings.


BTW the AES measurement results are nearly the same like other recommendations.
Or by the other hand I'd point out that +/- 50 Watt is nothing to talk home about for different drivers but familiar design construction.


IMO a lot of folks don't consider that it is not always a advantage to yield a very high "power handling".
(However my last cab design was done similar like fearfull designs ...)

But my next design will be a bit different, that means less driver Moving Mass and a higher fs and higher tuning for the cab as well.

IMO it is not possible to push all "advantages" in only one cab design ...

[Sid Fang]

Three pages, and no one has noticed that in the original quote they were probably talking about potential damage to the amp?

[bumperbass]

Originally Posted by Sid Fang

Three pages, and no one has noticed that in the original quote they were probably talking about potential damage to the amp?

Are we reading the same paragraph? The only path I see off of the original OP's post was talking about class D as 'digital'.