I don't call it 'cheating'- that would mean that someone sells something different than what they say they sell.
But it is sure that after the design process is done, many manufacturers have a final listening session where they can finetune 'voice' the product. Mostly done with speakers, but also electronics.
It is important that the unit sounds 'good' to a customer who auditions it, instead of looks good on the scope (yes I know it is not that black and white).
A noted exception was Peter Walker from Quad, he once told an interviewer that often he didn't listen to a new product until after it was in the stores.
Jan
This thread is about presumed cheating by treating the frequency response of amps and it is even stated
that this works with some automatism when a speaker is connected instead of a resistive load. Please read
everything. Can you show a single example of an amplifier with one of these features?
You have agreed to a conspiracy before in http://www.diyaudio.com/forums/digital-source/273021-sound-card-conspiracy.html of the same OP, but obviously ironically.
that this works with some automatism when a speaker is connected instead of a resistive load. Please read
everything. Can you show a single example of an amplifier with one of these features?
You have agreed to a conspiracy before in http://www.diyaudio.com/forums/digital-source/273021-sound-card-conspiracy.html of the same OP, but obviously ironically.
OK , I did not read the whole thread and am not planning to. But I'm familiar with voicing equipment - it already starts with the selection of the mike for the recording. So I am not surprised at the finding of the OP.
It is also true that combinations of amps and speakers (especially if the amp has highish Zout and the speaker has wobbly impedance response) can exerbate or cancel such things.
So there.
Jan
I still don't get what the issue is with an amplifier that is meant to give a nice listening experience and to improve this has some eq built in. No one of my friends that don't have anything to do with engineering and/or audio know what "frequency response" is and none of them care as long the music "sounds right".
10dB of 'voicing' with a solid state amp into a real speaker? I've not seen that since Bob Carver did it for his amp challenge. But as dvv told me on another thread I need to get out more!
Um, Quantum Asylum doesn't agree, from their web site: https://www.quantasylum.com/content/Products/QA401.aspx
Analog Input
Input Connector
Differential, BNC x 2 for Left and BNC x 2 for Right
Input Z
100K Ohm
Input Coupling
AC, Fc = 1.6 Hz
Input Full Scale, No Attenuator
5.6Vpp Single Ended (one input grounded) = 6 dBV = 2 Vrms +/- 2.8 Vpp Differential = 0 dBV = 1 Vrms
Input Full Scale, With Attenuator
56.4 Vpp Single Ended (one input grounded) = 26 dBV = 20 Vrms +/- 28.2 Vpp Differential = 20 dBV = 10 Vrms
Input Overload Protection
Yes, automatic overload protection up to +/- 56.4V
Input Noise Floor
-113 dBV (Input Shorted, atten off, 20 to 20 KHz, 32K FFT, avg 5, Hann, 48 Ksps)
THD
-108.5 dB (Loopback, single ended, L- shorted to ground, atten off, 32K FFT, 5 Hann, 48Ksps, – 10 dBV)
Isolated
Yes. The PC USB and digital section is fully isolated from the analog section (infinity ohms). Difference between the PC ground and the analog ground must remain below 30V.So maybe you should get rid of your protective voltage divider and try again.
Mike
In post #26 you said:
Hence my reference to the specs for the QA401 which say the inputs are overload protected and have a maximum input voltage of over 50 volts pp.
And what's the problem mentioning a product that is still in production? It happens all the time here and I haven't heard of any casualties yet.
Mike
Last edited:
Member
Joined 2009
Paid Member
Thank you for yet another tiny bit of additional information.
The model number of this 1981 Telefunken is still missing.
But it is very likely that the loudness was activated (post 1).
Please show us the "measurement" results of your amps also,
as offered for sale on amplificateurslegrand.ca and taken with
the same settings etc. Few people have test equipment like this,
QA 400, QA 401, QA 101 and what you call Tecktronics.
Thank you in advance.
I can't stop giggling at this. Everyone is bitching about this that or the other on this thread, and here's Bigun saying, "What's the problem?"
This proposition is complete BS. Many years ago, in the 1970s I started my career in a factory testing audio amps as they were completed. The response was flat with 3dB points at about 20Hz and 30kHz. In the ensuing years I have been involved closely in the "high end" audio business with several amplifier manufacturing companies. The tested frequency response of all audio amplifiers I had anything to do with would have been essentially ruler flat between at least 20Hz and 20kHz. There is no such thing as voicing an amplifier by tweaking it's frequency response, that belongs to the loudspeaker designer who must work with imprecise transducers. The OP is measuring a worn out pile of electronics from the beginning of the 1980s into an unspecified load. Time to close the thread.
Sent from my Nexus 7 using Tapatalk
Sent from my Nexus 7 using Tapatalk
Oh, that guy would be me, just for the record. Not trying to hide or anything.
I deleted it after realizing the point of the thread is not to laugh at weird stuff some companies do to fool the gullible. But to allege that the entire industry is doing it... which obviously isn't the case from all measurents read and personally done (Well I've read enough to know that the Sprout was a strange one!). To point to an example that exists, even if it represents just a small amount of all products out there, would add fuel to the flame of misrepresentation.
I can't stop giggling at this. Everyone is bitching about this that or the other on this thread, and here's Bigun saying, "What's the problem?"
+1
People buy stereos for enjoyment. If a non linear response gives more enjoyment then to heck with linearity.
It is a different story talking about a measurement amplifier.
I haven't ever measured an amp or CD player that was that tilted. Even my old Dynaco ST-35 was flatter. Odd.
But as was stated above, a lot of people need and enjoy some loudness curve. Most don't listen at mixing and mastering levels, so some loudness boost can help the tonal balance. Most consumers don't have great room acoustics, either, which can be helped by a recessed midrange.
To me it's only cheating if you claim flat response when there isn't one. Or is there a general expectation that all amps are flat?
But as was stated above, a lot of people need and enjoy some loudness curve. Most don't listen at mixing and mastering levels, so some loudness boost can help the tonal balance. Most consumers don't have great room acoustics, either, which can be helped by a recessed midrange.
To me it's only cheating if you claim flat response when there isn't one. Or is there a general expectation that all amps are flat?
The OP is talking about a tone control (where the knob is at "center" position). An amplifier (not tone control) is normally designed flat unless a tone control is built around feedback like some cheap vintage integrated amps (such as cheap Marantz).
I don't pay attention to TC design around feedback, but may be (a guess) there is difficulty there to make the response flat as the circuit is usually very simple. Who knows.
I don't pay attention to TC design around feedback, but may be (a guess) there is difficulty there to make the response flat as the circuit is usually very simple. Who knows.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.