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Author Topic: Subwoofer amps - what are we REALLY hearing?  (Read 31063 times)

John Roberts {JR}

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Re: Subwoofer amps - what are we REALLY hearing?
« Reply #10 on: February 05, 2008, 02:05:55 pm »

Alexander B Larsson wrote on Tue, 05 February 2008 12:46

Thanks for all the replies!

Don't you find it frustrating that we in this case not can quantify what we hear? And that amps that on paper are indistinguishable still do not sound the same, even within their linear operation (as in no clipping/current limiting).
Or do we fool ourselves - how big are the differences?

A few years ago I had the opportunity to pick up either of two Labgruppen amps for my bass guitar rig. One Lab 1000 or one Lab 1300. They are VERY close in spec, with most of the design the same, except the power supply. (The 1000 is a conventional and the 1300 is switched.) The price was the same, making the 1300 a bargain, as it is normally more expensive. However, there was no doubt the two bottom octaves where better with the Lab 1000.

And I have to carry the 20 or so extra pounds every time I move the thing...

/Alexander


It is disappointing that many unscientific and subjective observations confuse the understanding.  

I submit that in fact any difference you hear between amplifiers is non-linear behavior.  Clipping, current limiting, etc are far more common than people estimate. Even frequency response errors are nonlinear.

Clip limiters will also have a characteristic sound signature.

I don't deny that there are differences between amplifier in practice, but it's not all that mysterious. If the specs don't explain the differences you hear, you are looking at the wrong specs, or some other than controlled bench test situation.

JR




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John Roberts {JR}

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Re: Subwoofer amps - what are we REALLY hearing?
« Reply #11 on: February 05, 2008, 02:24:53 pm »

Ryan Lantzy wrote on Tue, 05 February 2008 12:27



I hate to even acknowledge this with a reply... but here goes.

FOR THE LAST TIME, THE DAMPING FACTOR OF AN AMP CAN DO NOTHING TO IMPROVE THE DAMAGE THE COPPER IN BETWEEN DOES TO THE DAMPING FACTOR!

It's VERY simple math.  Look into it.


In the interest of accuracy. I am familiar with a technology at Peavey that was intended to deliver arbitrarily high numerical damping factors (>3000:1). This circuit actually had the capability to deliver a "negative output impedance" so in fact this could actually compensate for copper (voltage not power) losses in speaker wire.

This technology was abandoned because it was a just a specifications number game and didn't deliver a real benefit to customers.  

So I agree with the thrust of your rant, but I would word it a little differently. "Damping factor is IMO not audibly significant in modern solid state amplifiers".

JR
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Elliot Thompson

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Sound Is Subjective
« Reply #12 on: February 05, 2008, 02:49:17 pm »

Alexander B Larsson wrote on Tue, 05 February 2008 16:11



Considering our ear's limited sensitivity to detect distorsion in the bass range, what IS it that we hear?



/Alexander



What "We hear" is subjective based on what we are looking for.

Top cabinets play a heavy factor which is always overlooked. This is why, even at a Sub woofer Shootout you cannot get a full understanding of the subs performance. Sure, it sounds good on the system being used. However, will it sound that way on your amps sitting below your top cabinets.

We also need to keep in mind what you and I hear can be totally different based on what we are focusing on, when we listen to the whole ensemble. Some just want the room to fill up with bass. Some want more punchy bass. Some want more extended bass. Some want to hear a particular frequency they've grown accustomed to from their own rig using xyz amplifier.

All amps offer their own characteristic when loaded with a particular sub cabinet. This is based on my experience owning Crest, Crown, QSC,  Peavey and a few other amplifier brands. How we decipher that sound in addition to whether it sounds pleasing or not is solely up to us to decide. For again, we are not listening to only the sub woofer – amp combo. We are listening to the complete system with the sub woofer – amp combo.

What I'm basically saying is trust your ears, understand what you are looking for and, rent (Or borrow) a few brands. Conduct your own listening test and, choose what sounds best to you.

Best Regards,
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Garry Anderson

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Re: Sound Is Subjective
« Reply #13 on: February 05, 2008, 03:44:56 pm »

"Real torodial transformers..... !"

Lets go back to the 'good-ol-days' of quasi-complimentry NPN output stages, massive EI transformers and 300W at 1% distortion.
Nothing has sounded the same since those days.
I'm sure these manufacturers only develop new technologies to make us buy new amps.... Laughing
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Richard Rajchel

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Re: Sound Is Subjective
« Reply #14 on: February 05, 2008, 04:11:16 pm »

These arguments are so ridiculous it's not even funny anymore. Arguing which amp sounds better and why is like arguing what shade of blue the sky is at 6pm just after a rain storm. It's so subjective, that there is no answer. More power? Sure, you think it should be louder, but the fact that our ears hear different frequencies at different "loudness" levels even if the measured SPL is the same confuses things even more. 130 dB at 80Hz will make a pile of rumble and may or may not sound loud, but 130 dB at 8000Hz will make most people run for their lives in pain. There is certainly a log rhythmic increase of cost for improvement in sound quality. The difference between a $700 Mackie mixer and a $1500 Soundcraft or A&H mixer might be quite noticeable to many people. The difference in sound quality between a $15000 Midas and a $100,000 mixer not 1 in 1000 people would be able to tell which is which in a blind audio test. Once you get to a certain point there's probably a .00001 % of the worlds population that can even tell the difference. The differences in amplifiers is probably much much less than that even....simply because there's only so much to an amplifier. A mixer is much more complicated and more components can have an effect on the sound. I would bet $1000 that if you took 100 engineers and setup an A/B blind comparison between a low end QSC amp and a Crown iTech and matched the voltage output of them both that the results would be 99% random. Sound is as subjective as beauty, or color, or political opinions. Someone will think it sounds incredible, and someone else might leave the show because the sound is so bad it's giving them a headache.

Name brand equipment is for people who have to fill riders, and to compare another subjective thing like customer service and reliability. The only people who know how reliable products actually are is the manufacturer that keeps track of repairs, and I'm guessing they don't share that information readily. I can find someone who's had 10 Behringer amps for the last 6 years running 5 nights a week without one failure, or someone with a Midas board that has to go in for repair at least 3-5 times a year.

Find tools that you are comfortable with and work the way you expect them to or are used to. You'll get the best sound you can that way. If you use an EQ with a constant Q of 1.5 and change to another brand that has something different and different circuitry it will react differently to what you are used to inputing for correcting that snare drum ring, or nasaly vocal tone, etc...

One last thing about "punchy" bass. What the heck does that mean in reality? Most people, including a lot of engineers think to get a great kick drum sound you need subs that go to 20Hz flat(OK I'm exaggerating a little), but that "kick in the chest" feeling is usually in the 60-80Hz range, and in all actuallity the first harmonic of 120-160Hz is where most of that feel comes from. you can EQ the crap out of a kick to get it to feel where ever you want I suppose, and kick drums obviously get tuned different and can be as big as a house or smaller than most floor toms, but this dream that you need to go super low to feel the kick in a live sound application is just flat out a lie. Compressed recordings are a completely different animal, so if you're a DJ don't listen to me...heh.
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Scott Smith

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Re: Sound Is Subjective
« Reply #15 on: February 05, 2008, 04:11:43 pm »

In no way did I intend to start a DF discussion.  Is the mention of "slew rates" a thing of the past as well?  
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Bennett Prescott

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Re: Sound Is Subjective
« Reply #16 on: February 05, 2008, 04:43:25 pm »

Scott Smith wrote on Tue, 05 February 2008 16:11

Is the mention of "slew rates" a thing of the past as well?

Yes. No modern amp should have any issue with slew rate limiting within the audible bandwidth.
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Chuck Fry

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Re: Sound Is Subjective
« Reply #17 on: February 05, 2008, 05:05:28 pm »

Bennett Prescott wrote on Tue, 05 February 2008 13:43

Scott Smith wrote on Tue, 05 February 2008 16:11

Is the mention of "slew rates" a thing of the past as well?

Yes. No modern amp should have any issue with slew rate limiting within the audible bandwidth.


And especially not when driving subs!  Rolling Eyes
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Greg Cameron

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Re: Sound Is Subjective
« Reply #18 on: February 05, 2008, 05:13:04 pm »

Richard Rajchel wrote on Tue, 05 February 2008 13:11

Arguing which amp sounds better and why is like arguing what shade of blue the sky is at 6pm just after a rain storm. It's so subjective, that there is no answer.


Yes and no. As has been stated many times here, not all amps behave the same when operated towards their limits. Different amp designs of similar power ratings will yield some performance difference with different boxes. There are differences and sometimes they're more then slightly noticeable.

Richard Rajchel wrote on Tue, 05 February 2008 13:11

The differences in amplifiers is probably much much less than that even....simply because there's only so much to an amplifier. A mixer is much more complicated and more components can have an effect on the sound. I would bet $1000 that if you took 100 engineers and setup an A/B blind comparison between a low end QSC amp and a Crown iTech and matched the voltage output of them both that the results would be 99% random. S


That's debatable. Sure, amps will probably sound the same - until they're pushed. And let's face it, most amps are pushed till they're nearly clipping at some point. Some will behave better then others. That's not subjective.

Richard Rajchel wrote on Tue, 05 February 2008 13:11

Name brand equipment is for people who have to fill riders, and to compare another subjective thing like customer service and reliability. The only people who know how reliable products actually are is the manufacturer that keeps track of repairs, and I'm guessing they don't share that information readily. I can find someone who's had 10 Behringer amps for the last 6 years running 5 nights a week without one failure, or someone with a Midas board that has to go in for repair at least 3-5 times a year.


While reliability is one factor in spec'ing gear, there are other tangible reason to go with using top shelf gear. If your statement was true, then a Behringer rig would perform up there at a fraction of the cost of L'Acoustics rig with a Midas board. Ain't gonna happen. Not so long ago, Behringer was consider shit for reliability and sound, so bargain basement is often not such a bargain.

Richard Rajchel wrote on Tue, 05 February 2008 13:11


One last thing about "punchy" bass. What the heck does that mean in reality? Most people, including a lot of engineers think to get a great kick drum sound you need subs that go to 20Hz flat(OK I'm exaggerating a little), but that "kick in the chest" feeling is usually in the 60-80Hz range, and in all actuallity the first harmonic of 120-160Hz is where most of that feel comes from. you can EQ the crap out of a kick to get it to feel where ever you want I suppose, and kick drums obviously get tuned different and can be as big as a house or smaller than most floor toms, but this dream that you need to go super low to feel the kick in a live sound application is just flat out a lie. Compressed recordings are a completely different animal, so if you're a DJ don't listen to me...heh.


If you've have an opportunity to mix on a rig that is truly capable of reproducing infrasonics below 30 Hz, you would see that there can be a significant impact on the quality of the performance compared to a similar rig which can't do much below even 40Hz. That's no lie...

Greg

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Garry Anderson

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Re: Sound Is Subjective
« Reply #19 on: February 05, 2008, 05:13:47 pm »

Thanks Richard for your informed reply, I've been trying to convince people along these lines without any result. Even offering explanations of why there are audible results have fallen on "deaf ears".

The only conclusion I have made from these discussions is that most people who frequent these ones are fixed in their ideas and don't won't to be admit to being mistaken or un-informed.
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