Amplifiers

Discussion in 'Soundcards, Speakers HiFI & File formats' started by DraZor, Jun 13, 2011.

  1. heymian

    heymian Master Guru

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    Yes but.. you're missing part of the equation. A higher sampling rate allows a higher frequency range to be reproduced, without aliasing or other anomalies. So by upsampling, you're essentially extending the frequency range. Now, at first you said these higher frequency ranges were inaudible.. so why would I want to extend my frequency range to inaudible levels by upsampling? That's why I said it was contradiction. You keep mentioning these "settings" as justification but as far as I can tell, the settings you're referring to are nothing more then environmental presets in windows like "Concert Hall" or "Underwater". I wouldn't say these are general sound improvements, but rather preference.

    Here is some information about frequency and bit-depths that might clear things up:

    Frequency (Sample Rate, or Samples Per Second)

    Sound is made up from pressure waves. A single constant wave has its frequency measured in Hz (oscillations per second). Humans can hear from a lowest frequency of 10's of Hz, up-to higher frequencies just below 20,000 Hz, or 20 KHz.

    When talking about digital audio, frequency has a different meaning, it is the rate each sound sample is recorded. Imagine you were told the temperature out side once a day, your friend was told the temperature four times a day, who would have the more accurate picture? your friend. The higher the frequency, the more accurate a representation, up to a point...human hearing can not hear above 20 KHz, so reproducing 50,000 KHz would be a waste of space (each sample takes up space). Nyquist's theorem states: that to reproduce a 22 KHz sound signal, it must sampled (recorded) at more than 2x the required frequency, a sample rate of 44.1 KHz can reproduce a 22 KHz signal.

    It just so happens that audio CDs have a sample rate of 44.1 KHz, so why is DVD audio 96 KHz, or 192 KHz? is it a marketing ploy? yes and no. Yes it is a ploy in that more appears to be better, it has already been said that an audio CD can reproduce a sound that has a higher frequency than people can hear. No, as it is easier (cheaper) to create a piece of audio equipment that plays back a 18 KHz signal without distortion, when fed a 192 KHz signal rather than a 44.1 KHz signal. High-end gear, would not have much distortion, so there is no point in 96, or 192 KHz audio, just the cheaper consumer gear which improves.

    Bit Depth (and Amplitude)

    8 bit has the worst detail, it looks coarse, for audio it sounds coarse, but there is not too much difference between 16 bit and 24 bit, they are both reaching the limits of perception. Audio CDs are 16 bit, whereas DVDs are 24 bit, again is it a marketing ploy? yes and no, yes most people cannot hear the difference between the two, no as 16 bit audio CDs have been spoilt by the loudness race: that is CDs produced now are volume compressed, that is the quiet parts are pushed up louder, so that when played on the radio or TV the track sounds louder (a 1980's CD would sound quiet in comparison to one from 2000). The downside is that 16 bit CDs are no longer effectively 16 bit, the full audible range is not being used. 24 bit helps, but in the long run, the same fate (loudness war) might happen to 24 bit DVD-audio discs.
     
  2. G-note

    G-note Master Guru

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    Hi Tom F could you pm me some links on some DIY kits please i would love that..
     
  3. ROBSCIX

    ROBSCIX Ancient Guru

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    Good choice. I find high end audio and DIY go hand and hand for many around here.
     
  4. RexAeterna1987

    RexAeterna1987 Member

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    no such thing as vintage AVR(audio/video receiver). there were some amps in the mid to late 80's that had video inputs for monitoring(like my 1985 yamaha R-9) but defiantly was built to be an audio amplifier first and foremost. they just added video inputs for monitoring use unlike modern AVR receivers where video inputs and special DSP are much more of concern in the equipment and gimped out in the amplifier section.

    op your soundcard should be fine. if your liking it then stick with it. you can get better sound but that's usually cause of special colorations that tend to be designed with these headamps circuit topology design giving the impression of better sound.

    i'm not a fan of headamps or fan of op-amps personally so this just my opinion.
     

  5. RexAeterna1987

    RexAeterna1987 Member

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    depends. the marantz should have more then enough juice for any headphone out today. what these old amplifiers have is just a simple dropping resistor between the speaker output power amp section and headphone out section. depending on the marantz sound you might like it or not. well i found quick schematic of it and seems to use pair of 330ohm@3w resistors at the headphone jack,so basically meaning if you say plug headphone of 330ohms you can push up to 3w's from the power amp section into the headphones.that's more then enough since headphones require miliwatts to reach their desired SPL(sound pressure level).

    like i said lot of these vintage amps be more then fine. i use them all the time to drive power hungry low impedance speakers and my 600ohm akg 240 sextetts and have no issues with either. get it serviced and you be set for life.

    i don't know about the denon since i haven't bothered looking for any service manuals or schematics on it.
     
  6. G-note

    G-note Master Guru

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    Oh cool thanks for all the info.I am so glad that I never sold that junk old receiver to a co worker for the two hundred he has offerd me for it..

    Wow!!

    My denon avr is entry level crap Also I think fee ser!!

    I wonder if it will drive 600 ohm cans just the same as the good ole' Vintage stuff??
     
  7. RexAeterna1987

    RexAeterna1987 Member

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    sorry for last response(i barely visit these forums)

    yea it should do more then fine with 600ohms. i use all my vintage amps for 600ohm akg 240DF's and 600ohm Akg 240 sextetts LP. might have bit impedance mismatch since the output impedance is 330ohms of your marantz where my amps i have an output impedance of 680ohms.

    even with the impedance mismatch they should sound great. let your ears be your judgement.
     
  8. TruMutton_200Hz

    TruMutton_200Hz Ancient Guru

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    You're still missing two vitally important things here.

    1. The Nyquist theorem assumes we have infinite bit-depth to work with, which unfortunately we do not. The bit-depth of our equipment is usually limited to 16, 24 or 32 bits. Sampling frequency and bit-depth act together as one, sort of similar to how pixel resolution and color-depth act together also (although this is still only a very oversimplified comparison because sound and picture are two entirely different things of course). The point is sampling frequency is completely meaningless without bit-depth and vice versa.

    2. Frequencies that are beyond the human hearing capability are not meaningless to sound quality. They interact with the frequencies we CAN hear. So even though we cannot hear them when they're being played back separately, we can hear the fact they're missing from our music. Hence, a more natural roloff of frequencies above the 20 kHz "barrier" can sound way more natural (read: less artificial) than an abrupt cutoff.

    The bottom line: given the right equipment, acoustic environment, music recording and hearing capacity there can be an entire world of difference between 16 bit 44.1 kHz material and 24 bit 96 kHz. However, the difference between 24 bit 96 kHz and 24 bit 192 kHz is rather very small even though it's nonetheless there. The same applies to the difference between DTS HD and DTS-HD MA for example.
     

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