Audible difference in class D 4,2,or 1 ohm load?

[helotaxi 5,000+ posts]

Setting 2 amps within 0.1 dB is easy enough with a simple DMM.

 

[VWBobby 10+ year member]

I suppose you could just match their output voltage (AC) with a test tone.... I was thinking more along the lines of trying to match their gains with an o-scope while playing music instead of test tones. Music will show the dampening effect, frequency range, etc better than a few test tones. More dynamic range with faster transitions.

 

[RAM_Designs 5,000+ posts]

I'll have to disagree on that point because one's ears are the absolute WORST quantifier when it comes to detecting differences in sound. Why? Because they are attached to a brain that is easily influenced by psychoacoustic factors. Furthermore, auditory memory is virtually nonexistent in most individuals.
I'll take my uncalibrated Behringer ECM 8000 or my calibrated Dayton EMM-6 over one's ears when it comes to measuring sound!

But if you don't like the sound it's pointless.

 

[VWBobby 10+ year member]

^^ very true. You can't tell me that some Boss/Legacy or other cheap amp that will clip at more than 50-60% output is going to sound good when its pushed at 80%. Usually when you start pushing the cheap amps is when the sound either gets "squashed" and sounds really punchy at the various frequencies or it sounds 'hollow' and not full like a quality amp with a strong power supply/capacitor bank. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Wingman0121 10+ year member]

You might run into "almost" useless changes to slew rate and damping factor in which 99% of the people won't be able to tell the difference.

Am I right that slew rate and damping factor only starts to matter when you're running like 5 pairs of full-range cabinets full blast like in pro audio?

 

[gunz4me2 10+ year member]

Damping factor really starts to matter when your runs of speaker cable are excessive lengths, as often seen in pro audio applications. My longest run of speaker cable was 100 feet when I had a DJ setup, and I routinely rocked the 50 foot setup. Regardless, a high damping factor was often touted as a useful feature to deal with the back EMF generated by the subwoofer over longer cable lengths. Unfortunately, damping factor has been over utilized as a misleading marketing tool when it comes to 12 volt amplifiers.

In a properly designed amplifier, slew rate is yet another useless spec.

 

[ciaonzo 5,000+ posts]

I agree, slew rate is largely unimportant to most listeners. It's not until you begin using drivers that can offer coinciding rise and decay times that you will be able to appreciate any difference at all. Extremely low mass, low inductance drivers with little to no energy storage and a flat impedance, mounted in enclosures that also do not store energy, will begin to reveal the differences in slew rate as well as different types and amounts of THD. Add in high efficiency and you can even begin to appreciate the difference in various amplifiers' noise floors. Some drivers even offer faster rise times than the very best of amplifiers (the Manger device with it's 13 uS rise time comes to mind) and you will certainly begin to hear differences in amplifiers with those. But most drivers used in the automobile simply don't offer the resolution necessary for splitting these kinds of hairs so it's not an issue. Take a look at the waterfall and impedance plots for some of these drivers and you can see why most suffer from phase distortion that smear detail.

 

[RAM_Designs 5,000+ posts]

I agree, slew rate is largely unimportant to most listeners. It's not until you begin using drivers that can offer coinciding rise and decay times that you will be able to appreciate any difference at all. Extremely low mass, low inductance drivers with little to no energy storage and a flat impedance, mounted in enclosures that also do not store energy, will begin to reveal the differences in slew rate as well as different types and amounts of THD. Add in high efficiency and you can even begin to appreciate the difference in various amplifiers' noise floors. Some drivers even offer faster rise times than the very best of amplifiers (the Manger device with it's 13 uS rise time comes to mind) and you will certainly begin to hear differences in amplifiers with those. But most drivers used in the automobile simply don't offer the resolution necessary for splitting these kinds of hairs so it's not an issue. Take a look at the waterfall and impedance plots for some of these drivers and you can see why most suffer from phase distortion that smear detail.

I love your posts, and as a result, love you. //content.invisioncic.com/y282845/emoticons/cuddle.gif.bd1b29c179c0482f8313dbd790b74c94.gif

Is that ok?

 

[RAM_Designs 5,000+ posts]

Unfortunately, damping factor has been over utilized as a misleading marketing tool when it comes to 12 volt amplifiers.

Agreed.

 

[ciaonzo 5,000+ posts]

I love your posts, and as a result, love you. //content.invisioncic.com/y282845/emoticons/cuddle.gif.bd1b29c179c0482f8313dbd790b74c94.gif
Is that ok?

My crotch just got all tingly so I'm gonna go with yeah.
















































































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