• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Can Audibility Differences Be Noticeable When Using A Broken Amp or A Poorly Measuring Amp for Subwoofer Duties

Trdat

Addicted to Fun and Learning
Forum Donor
Joined
Sep 6, 2019
Messages
967
Likes
396
Location
Yerevan "Sydney Born"
I added this in Psychoacoustics as I thought it is a audibility question rather than an engineering issue. Amir and others often mention that a not so good measuring amp can be "okay" for subwoofer duties. And I have always been curious if say a broken amp such as the

Sound Town ST-UPDM4C​

or a poorly measuring amp like the

Sunfire HRSIW8 DSP Subwoofer Amplifier​

can have a difference compared to well measuring amp if only used for under 120hz?

Potentially, I would love to know if its worth upgrading from poorly measuring Chinese amp(although I have no idea if my amp is broken or poorly measured) ? But also would love to know the psychoacoustics surrounding the this topic in terms of audibility with the sub frequencies.
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,425
Likes
7,941
Location
Brussels, Belgium
from a SINAD perspective 60 dB is what you would need for a subwoofer.

but an amplifier is much more than just its SINAD. For example, Research shared by KEF recently shows that for low frequencies you want amplifiers that are capable of high continous output rather than high instaneous output because the crest factor in music for these frequencies is incredibly low.

I personally use two Aiyima A07 with 4 passive subwoofers. it works fine and doesn't break the bank. But if i had one subwoofer with one gigantic woofer meaning that I'm not limited by excursion for most of the useable spectrum then the conversation would be quite different and i would get an amplifier with 500W or more of output.
 
OP
Trdat

Trdat

Addicted to Fun and Learning
Forum Donor
Joined
Sep 6, 2019
Messages
967
Likes
396
Location
Yerevan "Sydney Born"
from a SINAD perspective 60 dB is what you would need for a subwoofer.
Which is easily achievable, even the sundown has 75db SINAD.
but an amplifier is much more than just its SINAD. For example, Research shared by KEF recently shows that for low frequencies you want amplifiers that are capable of high continous output rather than high instaneous output because the crest factor in music for these frequencies is incredibly low.
High Continuous meaning not the dynamic range rather the power to continuously drive it with sufficient power?
I personally use two Aiyima A07 with 4 passive subwoofers. it works fine and doesn't break the bank. But if i had one subwoofer with one gigantic woofer meaning that I'm not limited by excursion for most of the useable spectrum then the conversation would be quite different and i would get an amplifier with 500W or more of output.
The Aiyimi looks like a light weight, its great it does the job.

I have ClassT/D Chinese amp which probably gets me 600 watts at 4 ohms but is rated at 900 watts at 4ohms powering a dual Dayton RSS315HO.

So according to your theory, power(continuous output) is more desirable for low frequency than anything else?
 
OP
Trdat

Trdat

Addicted to Fun and Learning
Forum Donor
Joined
Sep 6, 2019
Messages
967
Likes
396
Location
Yerevan "Sydney Born"
Good news, I save a lot of money. Jokes aside, my interest has emanated from the typical quotes that go along the lines that "it can be used for low frequency duties."

Would like to here other takes on this topic?

I quote @LTig from under the Sunfire amp thread review

"However I'm quite sure it is totally inaudible in all home installations"

So here is a second person who probably would maintain that audibility between a decent amp with a poorly measuring amp is negligible taking in consideration that perhaps the SINAD is above 60db and that it can power it continuously with ease.
 
OP
Trdat

Trdat

Addicted to Fun and Learning
Forum Donor
Joined
Sep 6, 2019
Messages
967
Likes
396
Location
Yerevan "Sydney Born"
Over the decades Stereophile has given great reviews to products that were then discovered to have serious defects.
Do they actually ever give any bad reviews?
 
OP
Trdat

Trdat

Addicted to Fun and Learning
Forum Donor
Joined
Sep 6, 2019
Messages
967
Likes
396
Location
Yerevan "Sydney Born"
No, but Stereophile often reviews bad audio components.
Exactly, so the point I want to make is that even if they heard distortion they would probably still review as good. Not necessarily testament to having a bad amp thinking it sounds good then when understanding that it actually measures horrible hearing the difference.

If an amp was reviewed and sounded good, then measured horrible and that person maintained that it still sounded good(honestly) that might give light to having no audibility differences in an amp that measures bad but that is not the case.
 

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
20,752
Likes
20,770
Location
Canada
A broken amp can include a distorting voltage amp section (Transistor is distorting the signal.) of the amplifier or even a negative or positive rail being distorted. It will sound slightly distorted and could even be mistaken for a dirty control.
 

FeddyLost

Addicted to Fun and Learning
Joined
May 24, 2020
Messages
752
Likes
542
can have a difference compared to well measuring amp if only used for under 120hz?
Amps that you've mentioned in question heavily distorted even frequency responce.
It must be audible compared to good amplifier without any doubt.
If your amp have flat FR and don't clip at your SPL, then you must expect decent subjective result. Maybe not good, but decent - it depends on exact parameters of passive sub that you're powering and amp itself. For sub you'll need decent damping factor at least, so not an valve amp typically.
I'd use simulator and apply 1,5-2x of clean
power predicted in your "worst case scenario" just to be sure. Big correction suck out power incredibly fast even if you don't really hear it.
 
Top Bottom