Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems WAV music into G68

I have WAV files on a harddrive and are looking for the best possible sound quality when from them when I use the Meridian G68 for reproducing the music.
So right now this might mean that I use a HD621 (apodizing filters, downsampling to 96 kHz) prior to the G68 (3x SPDIF connection). I could use a Sony PS3 with its USB input to decode the WAV format and send it via HDMI to the HD621. One alternatives at this time seems to be the Oppo BD-83, which can also accept WAV via USB and can decode it for output via HDMI. Which one provides a better SQ? Are there other devices which can convert WAV into HDMI and sound even better?

What about devices that decode WAV files and send the signal via SPDIF directly into the G68 for its D/A conversion (96 kHz)? Logitech Transporter?

Thanks for helping me to find the currently 'optimal' (sound quality) path to the G68.

Roger

Ok, you have a couple of options. I will just mention a few when connecting your PC/Mac to your G68.

Since you mention soundquality over and over then I will not mention the "ghetto" alternatives. ;-)

* Lynx AES16e PCIe card - Will output PCM to your G68 via SPDIF, VERY clean signal, low jitter! Troublefree!

* Ghetto alternative: ATI 4850/4870 HDMI GFX and soundcard. As ghetto as it gets with driverupdates and such, but I know you can get atleast 2ch 24/96KHz PCM out of it and it will go straight into your HD621. :]

Ok I did mention the "alternative" which I will probably try it's next incarnation in 6 months.

Lynxes are capable of seriously good sound quality BUT the software side is not as simple as say a SB Transporter.

For stereo I used to use a Lynx 2B in a PC running Foobar 2k with the SRC plugin. With that you had to make sure that all DSPs operations were either turned off (if not necessary) or done at maximum precision. Also the order in which various plugins ran had a noticeable effect on sound quality.

Essentially it can go from sounding like any halfway decent CD transport to sounding like a Meridian transport with the correct setup.

Just get a sound card (internal or external USB) that has 24/96 "bit perfect" SPDIF output. Using ASIO, or the new vista driver (I forget the name). Example EMU USB 0404 TASCAM 144. There are many others.

A more expensive option is a logitech transporter. But their may be a cheaper one coming along soon call squeezebox touch.

EDIT: Oops missed the HDMI requirement.

What format are those WAV Files in??? Even though you mention "96khz", I wonder if these files are standard 16bit / 44khz format?? Did they originally come from CD's??

I moved the SoX stuff to a new thread.

https://www.meridianunplugged.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=98235#Post98235

Thanks for asking the question Ronnie.

I found the SRC (secret rabbit code) upsampling plugin/code inferior to Meridian G68 upsampling. SRC incorrectly emphasize mid-highs and loses out on bass.

I would say the only thing that matters for WAV playback is that the PC should output bit-perfect! Everything else the G68 will better!

Thanks for the suggestions. I am still not "there" yet.

So the Ghetto soundcard allows an HDMI output from a PC into the HD621 for 2 ch 24/96kHz PCM. But the PC has to be close to the G68 and will add noise and 'complexity' to the home theater.

I borrowed a Logitech transporter which can do the 'bridging', i.e. picking up the WAV files from the network and transfering it via SPDIF digitally to the G68. So this does not allow to take advantage of the HD621's apodizing filters. I evaluated the sound quality of the Transporter solution (PC to Transporter to G68) versus the CD (Forsell transport to Audio Synthesis DAC to G68) with the same music material as the WAV file that was ripped from it. The transporter path was sonically close but the CD sounded more dynamic, presented more detail and definition of instruments and voices. What is likely to be predominantly responsible for the reduction in sound quality of the 'transporter path'? The disc drive in the desktop PC (Dell Precision T7400), the WAV ripping program (Eaxct Audio Copy), the network with the Linksys router, or the Logitech transporter? I hope it is not a little bit of each.

Is bandwidth and signal transfer rate of the network/router of importance? Does the transporter path the digital signal through or does it 'process' it in any way that affects sonic characteristics?

Is there any transporter-type of equipment with HDMI output at this time?

I really hope there is a way to retire the CD player path with its double D/A conversion without compromizing the sound quality of the music.

Since it has approximately the same frequency response before and after upsampling (confirmed by FFT) I would suggest you've got it backwards. The G68 rolls off the mid-highs and emphasises the bass. This is to be expected, since most upsamplers don't have a flat frequency response.

First, There is no way going through an extra D to A and A to D would supercede going direct. What ever you "like" about it, is what's "lost".

Second, you're refering a lot to 24/96 and taking advantage of apdizing in the HD621. Well unless the HD621 is UPSAMPLING the apodizing filters won't kick in. It's a process of the upsampler. So when using 24/96 material everything is bypassed. HD621 is straight through, G68 is straight through, DSP speakers are straight through. Only dejittering along the way.

Once you are at 24/96 the twiddle factor goes down. At 16/44 you can use G68 upsampling, resolution enhancement, or a 518 with more knobs, or the HD621 upsampler/apodizing filters or offline processing (Sox etc.).

And no it won't sound better if you downsample and reupsample, unless again you like what is "lost" in the process.

Can you explain this. How does the upsampler know it is upsampling a 200Hz signal as opposed to a 2000Hz signal? I thought upsamplers simply calculated the approximate value of a sample between two real samples. If it is easier, you could just direct me to a white paper that explains it. Thanks.

That, George, is exactly why I try to find the most direct way from a CD (Red Book) to the reproduction by a Mer G68 and analog speakers. Yes, I understand that a path from PC drive (ripping) > network router > network player > HD621 (Upsamling/apodizing) > G68 (D/A conversion to 24/96) > amp > analog speaker should in theory be optimal (least 'losses' and processing that can potentially degrade sound quality). Since my previous attempts to use this path did not result in a better subjective sound quality than the theoretically inferior "double D/A conversion" when I use a CD transport and D/A converter in front of the G68, I am asking for help which components of the all digital are most likely responsible for the reduction in sound quality. I would appreciate your and others opinions and experience with PC drives, network components and network players or 'bridges' so I can improve the digital path.

Thanks, Roger