Darren69 Posted July 12, 2015 Posted July 12, 2015 @@aechmea thanks mate and would love to drop in one day if the planets align. Always welcome at Che Daz.
Demondes Posted July 12, 2015 Posted July 12, 2015 I am using a PS Audio Directstream DAC after the DEQX for the mains (single amp). The DEQX still does the subs. The PS A DS is very clean and articulate, which is the sort of sound that I prefer. Mrs. A thinks that it is the best addition/upgrade for some time. However, I dislike its low output voltage, and so I have to play things close to full volume everywhere. These days the recording/mastering is my weakest link so an improvement here or there doesn't matter so much (to me). Yes I had psaudio DS DAC (sold on steronet) which is my benchmark. I was wondering if I could get away with just the dac in deqx. My issue is that I listen to well recorded jazz/blues/classical and then like Darren69 also love some badly recorded rock. I wonder if they changed the guts of the dac between hdp4 and hdp5? Apart from an obligatory upgrade to 192/24.
wanta911 Posted July 13, 2015 Posted July 13, 2015 OK I have a naive question: what exactly is the signal/processing chain through the DEQX? I am assuming that the filters are applied to the incoming digital signal after upsampling or downsampling to 24/96 and before they are processed through the DAC.......or are they applied after the DAC? I guess I am struggling to understand why the DAC is capable of 24/192 when everything will be 24/96 anyway? I remember when I had the external DAC connected via the BNC out that the outgoing signal was always 24/96 even without the filters on.
aechmea Posted July 13, 2015 Posted July 13, 2015 My understanding is that all inputs are upped or downed to 24/96 DSP is applied at 24/96 DAC-ed at 24/96 digitally controlled analogue volume
wanta911 Posted July 13, 2015 Posted July 13, 2015 (edited) My understanding is that all inputs are upped or downed to 24/96 DSP is applied at 24/96 DAC-ed at 24/96 digitally controlled analogue volume OK thanks, that's what I thought. So the unit itself is capable of accepting up to 24/192 before up/down sampling but the DAC will only ever receive 24/96. Edited July 13, 2015 by wanta911
davewantsmoore Posted July 13, 2015 Posted July 13, 2015 OK I have a naive question: what exactly is the signal/processing chain through the DEQX? I am assuming that the filters are applied to the incoming digital signal after upsampling or downsampling to 24/96 and before they are processed through the DAC.......or are they applied after the DAC? I guess I am struggling to understand why the DAC is capable of 24/192 when everything will be 24/96 anyway? I remember when I had the external DAC connected via the BNC out that the outgoing signal was always 24/96 even without the filters on. Before the DAC...... All incoming analogue signals -> digital ..... filters applied to the digital data ..... then convert to analogue "struggling to understand why the DAC is capable of 24/192 when everything will be 24/96 anyway?" I'm not sure if this is the case on the latest models or not .... but if it were the case, then it would be due to the DSP (doing the filters on the digital data) being only capable enough to handle 24/96.
Satanica Posted July 13, 2015 Posted July 13, 2015 My understanding is that all inputs are upped or downed to 24/96 DSP is applied at 24/96 DAC-ed at 24/96 digitally controlled analogue volume I have doubts about number 1 and 2. I have a strong suspicion that as long as it's less than or equal to 96K then DEQX will process it as such. Regarding number 4 you can turn the analogue volume OFF and use digital volume which would have to be applied at step 2.
Demondes Posted July 13, 2015 Posted July 13, 2015 I am using a PS Audio Directstream DAC after the DEQX for the mains (single amp). The DEQX still does the subs. The PS A DS is very clean and articulate, which is the sort of sound that I prefer. Mrs. A thinks that it is the best addition/upgrade for some time. However, I dislike its low output voltage, and so I have to play things close to full volume everywhere. These days the recording/mastering is my weakest link so an improvement here or there doesn't matter so much (to me). You are probably right about the recordings being the weakest link, and we are over analyzing lesser effects caused by DEQX etc. But my question is that since the DEQX processes everything digitally as 96/24 in that case you cannot feed 192/24 or DSD data direct to the PSAUDIO DAC if it is after the DEQX. Unless there is an unmolested digital pass through on the DEQX, but if that was the case then you could not correct the timings etc. So you end if giving up something in one area to gain in another. D.
wanta911 Posted July 13, 2015 Posted July 13, 2015 (edited) I have doubts about number 1 and 2. I have a strong suspicion that as long as it's less than or equal to 96K then DEQX will process it as such. Regarding number 4 you can turn the analogue volume OFF and use digital volume which would have to be applied at step 2. 16/44 is definitely upsampled, everything coming out of the DEQX is 24/96 as confirmed by 2 different DACs I have fed with the PreMate digital signal. You are probably right about the recordings being the weakest link, and we are over analyzing lesser effects caused by DEQX etc. But my question is that since the DEQX processes everything digitally as 96/24 in that case you cannot feed 192/24 or DSD data direct to the PSAUDIO DAC if it is after the DEQX. Unless there is an unmolested digital pass through on the DEQX, but if that was the case then you could not correct the timings etc. So you end if giving up something in one area to gain in another. D. Yep, which is one of the main reasons I am getting rid of my Vega - I'm just not using it to it's full capability. Doing without my bass management is non negotiable and getting rid of the DEQX is not an option at this stage after comparing it to MiniDSP/Dirac, although something a little more compact would be nice Edited July 13, 2015 by wanta911
aechmea Posted July 13, 2015 Posted July 13, 2015 You are probably right about the recordings being the weakest link, and we are over analyzing lesser effects caused by DEQX etc. But my question is that since the DEQX processes everything digitally as 96/24 in that case you cannot feed 192/24 or DSD data direct to the PSAUDIO DAC if it is after the DEQX. Unless there is an unmolested digital pass through on the DEQX, but if that was the case then you could not correct the timings etc. So you end if giving up something in one area to gain in another. D. Correct. I am using the PS A DS purely as a DAC using the coax input (which is always 24/96 PCM) from the digital out from the DEQX. I have no DSD data of any kind nor anything that will transmit I2S, so the other inputs on the PS are useless anyway - I'm not actually missing out on anything. Its just a DAC.
Satanica Posted July 13, 2015 Posted July 13, 2015 16/44 is definitely upsampled, everything coming out of the DEQX is 24/96 as confirmed by 2 different DACs I have fed with the PreMate digital signal. I don't think my HDP3 does up-sampling.
wanta911 Posted July 13, 2015 Posted July 13, 2015 I don't think my HDP3 does up-sampling. I think you are right. I found a DEQX thread from 2011 that suggested that the HDP-3 does not upsample: http://www.stereo.net.au/forums/index.php?/topic/36118-deqx/page-2 It has obviously changed with newer models. 1
aechmea Posted July 14, 2015 Posted July 14, 2015 What made me think that the HDP4 upped or downed to 96/24 was that the digital output is always 96/24 irrespective of the input, so something somewhere is changing the sampling rate, but whether that is up front prior to processing or down the back end I don't know. I never had the digital-out board option on my HDP3 so I don't know what dig output that produced. The other point that may be cause for confusion is that the HDP4 hardware manual says that the DACs are 192/32. I took this to mean simply that the DACs are of an oversampling design and did not imply that any other part of the processing was 192. Anyway, I'm not getting rid of mine any time soon whether it upsamples or not. 1
wanta911 Posted July 14, 2015 Posted July 14, 2015 (edited) Upsampling is theoretically a good thing as it provides headroom before the filters are applied, that is why the sampling rate must change at the front end. Edited July 14, 2015 by wanta911
davewantsmoore Posted July 14, 2015 Posted July 14, 2015 What made me think that the HDP4 upped or downed to 96/24 was that the digital output is always 96/24 irrespective of the input, so something somewhere is changing the sampling rate, I see. Even if it's not a limitation of their DSP ..... it is much easier to keep all the processing fixed at one sample rate. The other point that may be cause for confusion is that the HDP4 hardware manual says that the DACs are 192/32. Definitely. There isn't any point to state the DACs are capable of working with 32/192 .... if they're always being fed 24/96. Which (IMHO) isn't a problem (24/96 that is).
davewantsmoore Posted July 14, 2015 Posted July 14, 2015 Upsampling is theoretically a good thing as it provides headroom before the filters are applied, that is why the sampling rate must change at the front end. I suspect you are confused. "Headroom" is to do with the bit depth. Internally the DSP works at much higher depth than what it outputs.... eg. 32bits, or 48bits, or 56bit, or
wanta911 Posted July 14, 2015 Posted July 14, 2015 I suspect you are confused. "Headroom" is to do with the bit depth. Internally the DSP works at much higher depth than what it outputs.... eg. 32bits, or 48bits, or 56bit, or Of course - thanks for clarifying. So you are saying that the DEQX would process at even higher than 24 bit? I guess I am confused because even with no filters applied (bypass mode), the output is still 24/96. Which I guess isn't really a true bypass as there is still something being done.......
davewantsmoore Posted July 14, 2015 Posted July 14, 2015 So you are saying that the DEQX would process at even higher than 24 bit? Yes, internally. This is simply so there is no clipping of the signal... ie. so it has headroom...... It outputs the signal at 24bit. Remember the difference between 16, 24, 32, 56, or even 400bits ..... is not "quality".... it is about how loud the signal can be. 24 bits isn't higher quality than 16 ..... and outputting the signal with 24bits, isn't lower quality than the internal processing (which is probably @ 28 or 56 bits)
Guest Posted July 14, 2015 Posted July 14, 2015 Yeah @@Darren69 - ya gotta get Allan to do you an initial set-up to get things up and running. Especially important for non-speaker-designer-un-technical-consumer types like us. If you have designed and built speakers and cross-overs etc. and/or tinkered with acoustics, it may not be quite as puzzling. For me "who is Linkwitz and why does he drive a Riley" was a valid question, while, 1st and 2nd orders where things that happened at restaurants. Then in the fullness of time you can read the manual while looking at what Allan has done. Then things start to fall into place. Time then to build your own profiles. Even then some things remain a mystery - but you get there eventually. These days its a doddle but it wasn't always so. Knowledge and familiarity are king. Forget the other hardware bits and pieces and upgrades for the time being, and come to terms with the DEQX first. Great sound that could be all you will ever need. All very good advice Sent from my A0001 using Tapatalk
AudioGeek Posted July 14, 2015 Posted July 14, 2015 Anyone here used deqx correction witb electrostatic speakers?
almikel Posted July 14, 2015 Posted July 14, 2015 It would be nice for Alan Langford to come in and clarify, but my understanding is that internally the Deqx processes at 96kHz, even if the input is 192kHz, or 44.1kHz. I'm not sure if the bit depth increases from 24 bit to 32 bit anywhere in the process. In the digital recording industry, mixing is typically done with 32 bits so that you have 24 bits of resolution at the end - the same approach would be beneficial with heavy digital signal processing, or digital volume control. The paper is getting a bit long in the tooth now, but Mike Lavry makes some interesting points on samplig rate vs accuracy: http://www.lavryengineering.com/pdfs/lavry-white-paper-the_optimal_sample_rate_for_quality_audio.pdf Back in the day, respected amplifier designers like Quad would deliberately band limit their amps to keep signals that humans couldn't hear out of the chain to reduce inter mod distortion or amp instability. IMO there comes a point where higher sampling rates do not benefit, and potentially degrade the sound. cheers Mike 1
aechmea Posted August 5, 2015 Posted August 5, 2015 Anyone here used deqx correction witb electrostatic speakers? My friend uses a DEQX with Quad 2912 electrostatics (is that the right model number?) and a Velodyne DD18 sub. Works very well as far as I can tell.
aechmea Posted August 5, 2015 Posted August 5, 2015 Some new info on the input up-sampling question. Whilst looking for something else I came across the info text file for the 2 different firmware versions that came on the CD with my HDP4. The installed version of the firmware up-samples everything to 24/96, then processes at 24/96, etc. The other version of the firmware that was on the CD, seems to leave source at 44, or 88 or 96 or whatever. So it would appear that it depends on the model DEQX that you are using and the version of the installed firmware.
Darren69 Posted August 22, 2015 Posted August 22, 2015 Have just started a fortnight off work and you wouldn't believe it, the subs will be here Monday week. This gives me a whole week to sort it all out and then spend some time one day being a meat puppet for Alan on Skype and do the whole DEQX thang with Alan steering my pooter remotely. Will be the most interesting day for me yet, hi fi wise. Have never owned subs, let alone something that does what DEQX does. PS, ended up getting Canare sub leads. Everything there is ready to go. Naturally, will try to share the experience as accurately as I can through this communication medium. 1
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