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Amplifier Bakeoff: Purifi Eval1, McIntosh MA252 & Benchmark AHB2

BrokenEnglishGuy

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But this should be the last option to improve the sound impression. In my case, for example, it was a higher DF that achieved the goal. I also had such a filter before, which definitely had a positive subjective effect. But the higher DF then showed even more details and I could reduce my DSP use a lot.
Damping factor show to you more details...??? What.

Another case of placebo..
What speaker you have?
 

pogo

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What speaker you have?
Teufel M200/M6000 (1st Generation), since 30y.

And that is probably also one of the reasons why these differences are more apparent in my case:
Link

With other amplifiers with lower DF I had a stronger dull drone before. I corrected this with a DSP in the gain, which led to a subjectively better result. However, only the gain is corrected, but not the swing-out behaviour of the drivers, which also unnecessarily excite the room modes. A clear improvement is achieved with a higher DF and you are also rewarded with more details and less DSP input.
This is at least the case for my speakers, but it can also be useful to compensate for deficits in the low frequency range of other lsp with a lower DF.
 

pogo

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Here are two more aspects that I can only confirm from my own experience:

1)
The "frequency response" of impulsive signals in room looks completely different for each type of impulse composition - and has practically nothing at all to do with the frequency response in the steady state, which is determined by sliding sine, frequency mixtures or by narrowband noise.

2)
Filtering out resonances can make the sound more pleasant, but information is lost in the process.
The beat of a bass drum is already mostly over before the room even comes close to developing a resonance through standing waves! How should it then be possible to use a steady signal as a basis for correction in the bass range.

Source: Nubert electronic GmbH
 

BrokenEnglishGuy

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But you have the kef r3, right?
The low shelf filter its only for R series..

The r series lack of ressonances, distortion, woofer mechannical problems, etc. Thats why the low shelf filter works very well
 
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SIY

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1)
The "frequency response" of impulsive signals in room looks completely different for each type of impulse composition - and has practically nothing at all to do with the frequency response in the steady state, which is determined by sliding sine, frequency mixtures or by narrowband noise.
Your Nobel awaits.
 

pogo

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No, I don't have a KEF. You can build these filters for any lsp. I have recreated this in the DSP.
 

Geert

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The beat of a bass drum is already mostly over before the room even comes close to developing a resonance through standing waves! How should it then be possible to use a steady signal as a basis for correction in the bass range.
Because in the low end staty state corresponds to what we hear (perceive). In a room you can't hear the low end of a bass drum separate from the rooms acoustic response. It's why room correction works, no need to make it more difficult than that.
 

Geert

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The "frequency response" of impulsive signals in room looks completely different for each type of impulse composition
Any measurements that help us visualise this behaviour?
 

BrokenEnglishGuy

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No, I don't have a KEF. You can build these filters for any lsp. I have recreated this in the DSP.
Oh yeah but not all speakers, in first place, needs a low shelf filter like the R series.
For example these kef reference have much more stronger slope 20hz - >100hz
 

pogo

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In a room you can't hear the low end of a bass drum separate from the rooms acoustic response. It's why room correction works
That is correct! But if your system reproduces post-swings that do not correspond to the original signal, you will also unnecessarily excite your room modes/responses. And here they usually work with filters that lead to reduced details. A higher DF can be very helpful here and prevent this.
 

Geert

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That is correct! But if your system reproduces post-swings that do not correspond to the original signal, you will also unnecessarily excite your room modes/responses. And here they usually work with filters that lead to reduced details. A higher DF can be very helpful here and prevent this.
Which after more than 6 months repeating this same message in different topics is still nothing more than an unsupported claim.
 

Murray A

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The objective measurements expressed here and opinions of, including flawed listening tests, have not revealed anything new. Most of this was well understood at least 30 years ago. The basic issue remains of human perception within dubious controlled listening tests. There is a need to get back to the basic thresholds of sonic artifacts that are already known and documented.
 

rwortman

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My 2c.

BUT NO AUDIOPHILE after a listening sesion are going to tell you something like '' hmm, i find a bump at 66hz, and my golden ears says it's around +3dB, also there is a cancelation around of -2dB at 100hz ''.
You are going to need a microphone.

No one after a listening sesion are going to tell you how much nulls and enhancements in a room you have, in fact going to listening in a store a speaker and judge the woofer is the most worthless thing.
I don’t know about audiophiles, but professional sound engineers that set up systems in different venues every couple days for years sure can. I’m just an amateur so I need mic and sweeps.
 

Shazb0t

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All this "effort" and the OP can't purchase a basic multimeter. Why would anyone acoustically calibrate SPL levels at 110dB with a 1kHz tone??? Those Magicos are lucky to still be alive.
 

ahofer

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All this "effort" and the OP can't purchase a basic multimeter. Why would anyone acoustically calibrate SPL levels at 110dB with a 1kHz tone??? Those Magicos are lucky to still be alive.
Calibrated with a recording of a jet engine at takeoff, reproduced at realistic levels.
 

orchardaudio

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Interesting comparison esp. purify vs AHB2...
I am curious how Starkrimson GaN amp would place in the subjective ranking...

They just recently won budget product of the year from TAS. See the attachment.
 

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  • TAS_Product_Of_The_Year_2021.pdf
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Goodman

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They just recently won budget product of the year from TAS. See the attachment.
I just read the review, in measurements and comments; "depends largely on preamp selection" (not very informative.) Budget amp of the year 1500 dollars? Here is my 2 cents: '"on sounds very clear in treble range and very controlled bass response." Those comments could be applied to most decent class D amplifier. How about about the downside? like sounds thin, lack of weight, poor decay measurements, those are also characteristics and comments on most class D amplifiers. I wish Amirm could review this amp.
 

orchardaudio

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I just read the review, in measurements and comments; "depends largely on preamp selection" (not very informative.) Budget amp of the year 1500 dollars? Here is my 2 cents: '"on sounds very clear in treble range and very controlled bass response." Those comments could be applied to most decent class D amplifier. How about about the downside? like sounds thin, lack of weight, poor decay measurements, those are also characteristics and comments on most class D amplifiers. I wish Amirm could review this amp.

@SIY has measurements posted for this amp here:

They correlate with all the measurements that I have posted in this forum. Basically what I posted has been verified by a third party.
 
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