Head-fi topic - graph of RH1 freq response result

[doomlordis]

Hi, i was browsing Head-fi and found this topic http://www.head-fi.org/forums/showthread.php?t=216420 , Half way down Bangraman displays a rightmark graph showing a strange freq response from the RH1 , it had a dip between 3 - 10000 then a sharp rise up 19000 where it drops as expected. He claims it had no EQ applied?

I have recorded white noise from my RH1 (see result later in same thread) through headphone and line-out and get a flat frequency response. I just want someone else to check as i am sure that his result is wrong.

[greenmachine]

Hi, i can't give you any graph, but it seems his graph shows a much finer resolution in the dB scale (1dB, vs. 10dB in yours). Also no ones measurement equipment is 100% accurate, but at least the other guy has some other device to compare to so that you can see the relative difference (without calibrated measurement equipment there is no such thing as absolute value, but you can at least compare the difference between two or more devices).

Also, a slightly "colored" response (loudness effect) isn't necessarily bad, but can sound "pleasant" or even compensating over most headphones (which often show a contrary response - weak lows and highs) as others have pointed out. Also 1 or 2 dB isn't really much of a difference, just take a look at most headphones' responses, much more variation. Electric to acoustic transducers (headphones and loudspeakers) have always been the most critical part of the chain, and always will be.

[doomlordis]

When i zoom in on my graph to 1db range it is still flat. When i do the same test on my RH10 i get the lowpass filter as expected.

Edited January 8, 2007 by doomlordis

[e1ghtyf1ve]

When i zoom in on my graph to 1db range it is still flat. When i do the same test on my RH10 i get the lowpass filter as expected.

I get the same flat response. That graph looks bogus to me (mp3?? volume level? compression? POS Nano WTF??). But then I realized it was posted on Head-Fi. Mystery solved.

Cheers

[doomlordis]

Can someone else test please, i think the RH1 has a flat frequency response, Bangramans tests indicate it doesnt. I respect his skills and this needs further investigation.

[jbdance]

Can someone else test please, i think the RH1 has a flat frequency response, Bangramans tests indicate it doesnt. I respect his skills and this needs further investigation.

Here are my RMAA tests on the RH1 input with graphs. It looks pretty smooth to me.

Line input: http://beale.best.vwh.net/measure/audio/So...RH1_line-in.htm

Microphone input: http://beale.best.vwh.net/measure/audio/MZ...Mic_30_150Z.htm

Of course a good soundcard can do better:

http://beale.best.vwh.net/measure/audio/Mia24_96.htm

but that card and the PC it fits into, does not fit in a pocket.

...Wait, I just realized you're talking about the RH1 OUTPUT! Sorry, I have not tested that. I only use the RH1 for recording, and digital upload to PC. (as an aside, I find that a 1 dB volume difference is not easy to hear)

Edited January 10, 2007 by jbdance

[doomlordis]

Can you test the ouput jbdance?

Thanks

[jbdance]

Can you test the ouput jbdance?

I could at some point, when I find time. But meanwhile, try this. That graph shows (approximately) a variation as follows:

40 Hz: +1 dB

300 Hz: 0 dB

2 kHz: -0.4 dB

10 kHz: 0 dB

20 kHz: +1 dB

Ok, so what does that mean? You can find out. Set that equalization curve up in the audio editor of your choice. I use Vegas. "Audacity" can apparently load in EQ curves, although I don't know in what format.

Try listening to your favorite music on your favorite headphones both with and without that level of EQ applied. Does it sound much different to you? ...really?

I just did this experiment, using the track EQ in Sony Vegas 7 and listening to a variety of music, switching the specified EQ curve in and out. I concentrated and listened closely. I could hear no difference. I increased the 40 Hz boost and I did hear a difference around +6 dB. Your hearing may be different, but my point is the EQ curve as described is pretty close to negligible from my standpoint.

[Qwakrz]

I think the main problem is with using a set of headphones to load the output down is that they are an active load and will introduce distortions in the frequency repsonce.

If you want to load the output with a headphone like impedance then you need to use 2x 64ohm resistors in the stero plug. Using headphones will put an inductor inseries with the output and cause different resistances at different frequencies, depending in the headphones used you will get high points and low points in the frequency graph on anything but a high power output device that can over-drive these problems (exactly what the wrong graph shows).