Quality of Direct vs Stereo (Onkyo 595 and other Receivers)

Discussion in 'Archived Threads 2001-2004' started by Michael WH, Aug 10, 2001.

  1. Michael WH

    Michael WH Auditioning

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    Hi all,
    I have just upgraded my AV Receiver from the Onkyo 525 (1995) to the Onkyo 595.
    This took me from just Dolby Prologic to Dolby Digital, DTS, and Prologic II.
    I have my CD player connected to the new receiver using digital coax.
    The 595 sounds better than my old receiver when playing CDs in Stereo mode (this was big a surprise as I was not expecting any improvement). The music seems to more naturally have a full dynamic range, and I can hear words which I could not hear before.
    Unlike the 525, my new 595 has a Direct mode (where the signal bypasses the tone controls and maybe other processing).
    My next big surprise was that the Direct mode sounds different from the Stereo mode. Initially it was like I needed to turn the treble tone control 30 degrees to the right to make the Stereo sound about the same as the Direct.
    This made me think that my new 595 might be faulty. I bought a sound level meter (Radioshack analogue) and compared the Direct with the Stereo (tone set to neutral) using Pink noise in 25 steps from 25Hz to 20KHz. I expected to see a difference - there was none! The frequency response of Direct and Stereo was exactly the same!
    For most CDs, Direct sounds better. There is much more detail, the sound opens up, is more transparent. In fact, Direct is so good that it makes me want to listen to my whole music collection again!
    But remember that Stereo is not faulty, in the sense that Stereo in the new 595 does sound better than on my old 525.
    My questions to this group are:
    Do others hear a noticable difference on this or other receivers between Direct and Stereo?
    How do people describe the differences?
    Does anyone know what is causing the differences?
    What measurement could be made that would show that there is a difference?
    I have read here of people saying that they like to listen to music using Prologic II on the 595. Whilst I need to explore myself the difference between Stereo and Surround (Music), I have not done so much because to me the Direct is far superior for music than either Stereo or Surround. What do others think?
    Regards,
    Michael Wilbur-Ham
    Melbourne, Australia
     
  2. Rob Roth

    Rob Roth Stunt Coordinator

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    Well mate, looks like you've got a winner. The better receivers and pre/pros often have a 'direct' or 'bypass' mode for the reasons you are experiencing. A little history: When HT first became popular many "audiophiles" laughed at the quality of two-channel reproduction in the systems. Some of their more valid concerns centered around the use of extensive processing of the digital bit stream for bass management and other features which are very valuable for HT but which are anathema for the tweo channel purist who wants as few signal stages between the source and his listening as possible. They also claim that unless the speaker array is very precisely positioned the 'extra' speakers can create comb filtering effects that destroy imaging and filter out some frequencies.
    I personally switch back and forth beween several modes; even on 2 channel material. Some sounds better played through all seven speakers and two subwoofers, other sounds better played two channel direct only through the front speakers.
    One reason you may be experiencing 'extra' treble on Direct is that the bass management is not engaged and your subwoofer is not outputting; thus leading to an apparent increase in highs.
    Since I use my system extensively for music (2 channel and multi-channel) I run all my speakers full range to avoid the bass management processing.
     
  3. Michael WH

    Michael WH Auditioning

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    Rob,
    All my comparisions have been done with just the two main speakers (Jamo 507-A from 1995). I don't have a sub connected, so the receiver is set to sub=no.
    I'm still surprised that the processing makes such a difference to the sound, and would love to know what measurement I could make to show this difference.
    I'm also surprised that from my net searches (this forum, other newsgroups, and reviews) there is very little discussion on this topic.
    Whilst the Onkyo 595 is an excellent home theatre receiver for the price, it is an even better stereo music amplifier when played in Direct.
    Maybe it is also telling that this thread has generated very little interest in a home theatre forum. Yet many home theatre people say that they use their equipement for ordinary music listening over 50% of the time, so I would have thought that there would be a combination of home theatre and hi-fi interests.
    Are these two worlds really that different?
    Michael
     
  4. Thomas_Berg

    Thomas_Berg Screenwriter

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    Thomas
    i have the 595 and a Marantz CC-4000 connected to it via digital coax. i too have noticed a difference in the sound (stereo vs direct). here's what i found:
    i have 2 subs (i guess). one is the cheapie that came with my CSW Ensemble IV package and has the crossover for the speakers running thru it. the other is my SVS 25-31PC routed thru the sub out in the receiver. when using the direct mode, the sound is brighter. i guess this is due to the lack of bass, 'cause only the cheapo "sub" plays low.
    when i switch to stereo mode, the SVS takes over. not dominating the sound, but definately there adding to the music. i think once i move into my dorm and run the speakers thru the crossover in the SVS (without the cheapie at all), i will be able to judge a difference a little better. until then, all i've really noticed is the lack of bass in direct mode.
    ------------------
    -Thomas
    Click here to visit my webpage.
     
  5. Steve_D

    Steve_D Second Unit

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    This post prompted me to calibrate my sub for direct mode on my 3801 (versus using stereo). I was able to get much smoother freq response in the direct mode...in fact +-4 db at my listening position versus +-6db in stereo, and as important not nearly as much EQ'ing of the sub. These are hard, objective numbers I'll be glad to show the charts of, so I'm convinced direct is the way to go. Also, Stereo and Direct have much different calibrations...which is probably why someone said his sub comes alive in stereo. Calibrate each of them and there shouldn't be a huge difference in overall level. I calibrated Matrix also, since I use that for TV.
    I wonder though, I'm pretty sure direct mode only bypasses the tone controls....It still has to be doing SOME digital processing for the sub out to work.
    The analog bypass mode, on the other hand, does no processing and there is no facility for bass mangement on these inputs.
    ------------------
    http://www.sdiver.org
    [Edited last by Steve_D on August 12, 2001 at 11:24 PM]
     
  6. Burke Strickland

    Burke Strickland Second Unit

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    Michael -
    It isn't a fluke -- "direct" mode really does make a difference! I'm glad you've discovered what a treat this mode affords and are "rediscovering" your CD collection because of this serendipitous good fortune..
    I may be one of the people you referred to when you said that many folks around here say they use their HTs for music listening more than 50% of the time. (In the past few months, my percentage of HT time devoted to music has gone even higher than that.) When I was shopping the past few months for a new pre/pro, I wanted to find a unit that could serve not only as a state-of-the-art surround processor for movie soundtracks, but would also give me audiophile-caliber performance with two channel music. So "direct" mode for analog inputs was one of the primary items on my "required features" list.
    I am happy to say, I found the right unit at the right price, and it is manufactured by a division (Integra Research) of the same company that produced your new receiver. While my pre/pro's "stereo" performance is good enough to use when I really must have the sub engaged, "direct" mode provides the purest form of sonic pleasure, and gets used often. I'm glad that is a feature they include in a lot of models made by all their consumer electronics divisions.
    Enjoy!
    Burke
     
  7. Paul_Psutka

    Paul_Psutka Stunt Coordinator

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    Michael, I'm glad someone started a thread like this!
    I was very concerned about getting a Dolby Digital/DTS receiver. For years I had been using a simple Dolby Pro Logic receiver and I was using the high pass and low pass filters on my sub by having the sub hooked up thru the pre-out/main-in loop on the receiver.
    I didn't want a new receiver to degrade the signal with it's bass management. I thought I'd compare the Direct vs. Stereo modes on some receivers that actually had these options (Marantz, Denon, and Onkyo).
    I auditioned the Marantz SR-7000 in a store, and had the fronts set to large with sub off. I then compared the Stereo vs. Direct modes. My source was the analog inputs from a CD player. Both modes played the front speakers full range without a sub, but there is analog to digital to analog conversion going on in the "Stereo" mode. There was a very noticeable difference between Stereo and Direct. The Stereo mode was inferior sounding... less depth, flat sounding, the highs not as airy and open. This disappointed me because I was hoping I wouldn't hear much of a difference between Stereo and Direct.
    I then did the same comparison on an Onkyo and couldn't really hear a difference. I ended up buying an Integra 6.2 (like the Onkyo 696) and spent a lot of time comparing the Stereo and Direct Modes. Again, my inputs are all analog.... I don't own a DVD player yet. And this time I had my fronts set to small with the sub on for the STEREO mode. Direct mode bypasses A-D-A conversion and bass management and sends a full range pure signal to the fronts. I have my subwoofer volume adjusted so the bass level is similar when switching back and forth from Direct and Stereo modes. I'm happy to say that the Onkyo's A-D-A and bass management filters are very transparent. I didn't really notice a difference between Direct and Stereo modes. I do enjoy switching between the 2 modes, because on some material I like to hear my front speakers full range without a sub, and on other material I want my fronts set to small with the bass redirected to the sub..... therefore the Stereo and Direct modes work perfectly for this switching.
    Steve,
    From what you said, and also from reading the Denon 3801 manual online, it seems that the subwoofer still operates in Direct mode? the manual said something about reducing the subwoofer level one more notch below -12dB to turn the sub off.
    I've been considering the purchase of a Denon 3802, but have been hesitating because I'm not sure if the Direct and Stereo modes will be similar to the Onkyo's performance. (I sold my Integra 6.2 for other reasons..... the 46watt x 5 tested power output).
    A Direct mode should bypass all bass management, and should send a full range signal to the front 2 speakers. But maybe if you're using Digital inputs, then the Digital to Analog conversion has to take place and so the bass management can be added in too? Perhaps analog inputs would bypass the bass mgmt and no signal would be sent to the sub?
    Also, in other receivers like the Harman Kardon 510, I think that in the Stereo mode (doesn't have Direct and Stereo modes) the front speakers can only be set to large, but then you have the option of adding the subwoofer along with the fronts being played full range. I dislike how you can't have the fronts set to small in the stereo mode of the Harman Kardon's.
    Whew!! did I write all that? [​IMG]
    Paul
     
  8. Saurav

    Saurav Cinematographer

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  9. Michael WH

    Michael WH Auditioning

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    On the Onkyo 595 the Direct mode does NOT use the sub, but I the Stereo mode does use it (if connected).
    So the 595's Direct mode is maybe the same as the 3801's Analog Bypass mode.
    In my set-up I don't have a sub, but my main speakers don't do a bad job at the low end.
    (At an average testing level of 72.1 db, the bass is 7.1db down at 31.5Hz, 2.6db down at 40Hz, and 0.6db down at 50Hz).
    So when I compare Direct and Stereo I'm doing it with only the left and right main speakers for both modes.
    With people doing the comparison who have a sub for the Stereo mode, you will also be hearing the difference between the sub being used or not used. In this case the Stereo mode should have a better low end (otherwise you would be better off without the sub!).
    If you wanted to do the comparison without the use or non-use of the sub, then you would need to switch your sub off, and select sub=no on your reciever. Though you will now get worse low end, the low end will be the same for both Direct and Stereo. You may then hear better the difference in clarity that has so impressed me.
    Thanks for everyones comments!
    Michael
     
  10. Gil D

    Gil D Supporting Actor

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    Paul,
    I am returning my Onkyo 696 since I feel that the unit was not transparent enough for me when used with my SACD player. I have used Denon and Sony ES receivers in the past as a preamp and was pleased with the sound but could not come to grips with the Onkyo sound. Iwas able to find a new Denon 3801 at a good price and so far I have been very pleased.
    In a recent issue of The Perfect Vision the Denon 3801 was deemed very transparent for SACD and the sub feature on using the direct mode (read the Denon rebuttal) is a big plus for those using bookshelfs and a sub. An analog high pass filter is employed for the mains preserving the analog signal from an SACD or other CD player to the mains, while the low frequency content is digitally processed and output to the sub preout. So far it works very well for 2 channel SACD since the 120Hz crossover of my Sony SACD changer's bass management feature isn't to my satisfaction.
    If you are used to the Onkyo sound, keep in mind that you may not like the Denon sound.
    [Edited last by Gil D on August 13, 2001 at 04:28 AM]
     
  11. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    I'm running "small" bookshelf speakers and a sub with my 595. So when I switch from stereo to direct there is a big difference, but I've always attributed it to the lack of bass - no subwoofer output. And I've always assumed that I would get superior sound, especially at higher volume levels, in stereo mode since the bass management with all speakers set to small allows me to effectively have an active bi-amp setup. The amplifiers in the receiver are no longer required to produce much output in the bass regions, so there's more power available for the rest of the spectrum.
    It makes sense that if you're running your front speakers "large" then you'd get better performance in direct mode. But those of us who run them "small" may actually be better off in stereo mode.
     
  12. Steve_D

    Steve_D Second Unit

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    Paul,
    Yes, your interpretation is correct. As long as you are still using the digital in connection, thereby using the Denon to do PCM decoding, you still get bass management and use of the sub out jack in direct. In fact, I now have evidence that in Stereo mode the Denon 3801 does some tone contouring even with all tone controls set to 0. So direct digital mode basically bypasses some of the receivers digital circuitry, but obviously not all otherwise it could never decode PCM nor apply bass management.
    Assuming Gil is correct, direct mode must work different if you are using the analog inputs, and I like what I read for my upcoming SACD player with the analog section and limited digital bass management.
    Yes, you can turn sub completely off in direct mode. This is perfect if you like to use Main L/R without sub (or the resulting 80 HZ crossover) for 2 - Channel, but still want the sub active for movies, without having to change settings small large in the main menu.
    The Analog bypass jacks bypass all digital circuitry, which makes me wonder how they do volume control, they must have both a digital AND analog volume control section. The analog bypass actually has a very respectable 103 S/N ratio.
    [Edited last by Steve_D on August 13, 2001 at 08:31 AM]
     
  13. Paul_Psutka

    Paul_Psutka Stunt Coordinator

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    Gil and Steve,
    thanks... I'm going to check out the back issue of the Perfect Vision when it becomes available for $6 soon.
    I only owned the Integra 6.2 for a few weeks, so I'm not dedicated to the Onkyo/Integra sound.
    Probably the best thing for me to do would be to order the Denon 3802 from a store like Abt Electronics which has a 60 day money back policy.
    I'm curious as to what the new Onkyo 898 will have to offer, since it will list for $500 more than the 797. The 898 at $1499 (list) might be hardware or software upgradeable like the 989? hmmm. I hope they're not charging $500 more just for 110 vs. 100 watts, and 7 vs. 6 channels of amplification.
    Paul
     
  14. Paul_Psutka

    Paul_Psutka Stunt Coordinator

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    Gil, I picked up July/August issue of The Perfect Vision at a newstand today. Unfortunately, it didn't really help me with my Denon vs. Onkyo decision. It wasn't like the reviewer said one was preferred over the other for 2 channel stereo listening.
    Are you saying you didn't like the sound of Onkyo's DIRECT and STEREO modes?
    I was all keen on Denon's design when I read one of their technical sheets a year or two ago. It explained what you said about the Denon:
    "An analog two channel bypass routes stereo analog audio past the DSP section, providing straight-through signal purity. A parallel bass management circuit provides analog high pass and digital low pass filtering for the main left and right speakers and the sub-woofer,which provides superb analog signal transparency through to the main left and right speaker outputs. This preserves analog signal integrity especially for high resolution signals like analog LP and HDCD-encoded CDs. Competitive A/V components typically "digitize" all incom-ing analog signals, even during simple stereo operation."
    In Denon's rebutal..... they are obviously going to point out how important this is for marketing reasons. It's hard to know if a company really thinks this is the best way to do things, or if it just happened to be their way of doing things and so now they will market it as a unique and positive feature.
    I emailed the above Denon text to some other manufacturers, like Onkyo, NAD, and Rotel last year... asking them how they do their bass management with analog sources. The replies were generally "we've never heard of that way of doing things" or I didn't receiver a reply at all.
    I spoke with Doug Blackburn from Soundstage! magazine about Denon's way of doing things, and his reply was as follows:
    "some of the newest, and generally relatively expensive surround processors have removed all analog signal filtering having to do with bass management and moved it all to the digital domain, where, if done correctly, there should be no degradation of sound when you enable the LFE subwoofer channel or set any of the other speakers "small."
    And Mr. Blackburn felt that analog filtering was destructive to the sound, if I understood him correctly.
    I thought it would make sense that the high passed signal above 80Hz was kept analog, especially with analog inputs. Why convert it to digital and then back to analog again? but I guess if done correctly with high quality convertors, the digital filters will be less destructive to the sound.
    I think I read of phase problems with analog filters.
    Also, re: The Perfect Vision..... it disappoints me that the current issue tests the Denon 3801 and Integra 7.1, as well as the Toshiba 56H80 HDTV -- when the 3802 is now available, the Integra 7.2 is due out in Sept or October, and the Toshiba 57H81 is now available! They should have tested these older models for a few issues ago! or waited another issue or so for the new models! [​IMG]
    Paul
    [Edited last by Paul_Psutka on August 14, 2001 at 08:54 PM]
    [Edited last by Paul_Psutka on August 14, 2001 at 08:55 PM]
     
  15. Steve_D

    Steve_D Second Unit

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    I disagree with Mr Blackburn's statement, and I bet if you posted that response to Audioasylum you would get a hearty round of laughter. When done correctly, analog to digital to analog will result in no degradation of sound? huh? In the audiophile world, most HT processors are looked at as sub-adequate for 2 channel precisely because they do that analog-digital-analog conversion. When done correctly is the key phrase here maybe....what is the sampling bit rate and freq "when done correctly"? I bet its no where near what these
     

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