Solution for low bass on HD-A1 using analog 5.1

Discussion in 'Playback Devices' started by Pete T C, Jul 16, 2006.

  1. Pete T C

    Pete T C Second Unit

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    May want to add this to the FAQ, but it is also worthy of its own thread.

    When using the analog 5.1 outputs of the HD-A1, some users may experience a lack of bass compared to using the digital optical/coax output with their receiver. However, due to the possibility of enhanced quality using DD+, many prefer to use the analog 5.1 over the digital optical/coax output.

    This is due a 10db LFE output level difference when using builtin DVD decoders and certain receivers/preamps. If you have this issue of low LFE using analog 5.1s, follow the below steps:

    NOTE: Do not perform these steps unless you are having LFE issues!

    1. Ensure levels are balanced with digital optical/coax output first (use THX optimizer for example to do this).
    2. Enter Toshiba HD-A1 setup menu, click on Audio, click on 5.1
    3. Ensure all speakers are set to Large/0ft, subwoofer is set to Use and crossover is set to 120hz. This will essentially bypass this portion of the decoder as most receivers will apply your receiver-set speaker volume levels/bass management globally across the digital and analog inputs.
    4. Hit Next, now set the volume levels on the HD-A1 for left/center/right/left surround/right surround to -10db and subwoofer to 0db. Again, that is set all channels on the HD-A1 to -10db except subwoofer which should be set to 0db. This will effectively boost the LFE by 10db and rectify the LFE volume difference between analog/digital inputs for receivers that have this issue.
    5. Exit setup menu and you are set! LFE level is where it should be.

    I used this procedure on the HD-A1 alongside my Parasound AVC-2500u to correct the bass discrepancy between the analog 5.1 inputs and the digital inputs, and it should work on any receiver where the 10db difference is found. Hopefully in a future firmware upgrade Toshiba will add a toggle option to boost the 5.1 analog LFE by 10db so the above setup procedure is not necessary.
     
  2. Harminder

    Harminder Second Unit

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    What's funny is that when I use the optical/coaxial outputs, the LFE is extremely low. But when I use the 5.1 analog outputs, the LFE is amazing and that's without making any adjustments in the HD-A1 menu.
     
  3. Steve Tannehill

    Steve Tannehill Ambassador

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    Some receivers also offer offsets in 5.1 analog mode, so this procedure is a combination of player settings and receiver settings for me.

    Don't forget test tones and the SPL meter to make it perfect.

    - Steve
     
  4. Pete T C

    Pete T C Second Unit

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    Good advice!
     
  5. Travis Hedger

    Travis Hedger Supporting Actor

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    I need to get me an SPL and give this a shot.
     
  6. Paul Arnette

    Paul Arnette Cinematographer

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    Pete T C,

    Thank you for posting this. I have a question though. When you say lack of bass, I assume you were getting some bass before. Any suggestions for someone who is getting no bass at all?
     
  7. Pete T C

    Pete T C Second Unit

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    Are you sure the LFE output is enabled?

    If you are getting no bass at all then:
    a) lfe output on hd dvd or lfe input on receiver is disabled
    b) lfe output on hd dvd or lfe input on receiver is broken
    c) cable between your HD DVD and receiver is defective
    d) components are setup wrong

    Tell us more about how you have it wired up. Make sure you enable the LFE output on the Toshiba's 5.1 setup menu.
     
  8. Paul Arnette

    Paul Arnette Cinematographer

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    Pete T C,

    As I mentioned in the PM I sent you, I discovered that there is indeed a problem with the subwoofer cable I was using. I have a replacement cable on the way. Once I receive it, I am wondering if I then receive some bass, which I expect I will, how should I leave the Speaker settings on the Toshiba HD-A1?

    I ask this because I am confused where is best to make the speaker size, distance, and level adjustments. I would think it would be preferable to do them on the receiver side. If so, should I leave the Tosh Speaker settings at the default. What was the default again?

    Thanks.
     
  9. MTrotter

    MTrotter Stunt Coordinator

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    Question:

    I thought I read this was a software problem, specifically with WB titles in which WB set the LFE too low? Does this affect all HD-DVD discs?
     
  10. Pete T C

    Pete T C Second Unit

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    There are three discs where Warner set the *master* volume 10db too low, which was fixed in later discs. The LFE problem may or not affect you depending on your receiver, it has nothing to do with HD DVD hardware/software but rather the different way receivers handle the incoming analog LFE channel versus a digitally decoded LFE channel.
     
  11. Steve Tannehill

    Steve Tannehill Ambassador

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    The bass levels are still out-of-whack (technical term) when you feed the analog 5.1 channels the player-generated test tones. This procedure, in conjunction with settings on your A/V receiver if applicable, will rectify the situation.

    - Steve
     
  12. Brajesh Upadhyay

    Brajesh Upadhyay Supporting Actor

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    My receiver is the Pioneer VSX-1015TX. With its test-tones & a SPL meter, I've calibrated the sound to where it should be. Test-tones can be heard from all channels, including the sub.

    However, when I follow Pete's steps, I still don't get the HD-A1 generated test-tone out of the sub, only all the other channels. Will multi-channel still work fine w/an actual HDDVD disc w/DD+ however?
     
  13. Paul Arnette

    Paul Arnette Cinematographer

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    Brajesh,


    I'm not 100% sure what you are asking here, so I will just say this. When I followed the instructions in this thread, including the -10db part, but not the crossover, instead I used 80hz, I was able to play portions of Serenity fine, I had sound coming from all the speakers including the sub over multi-channel. So, while I want to say, yes, I'm still not sure totally of what you are asking.
     
  14. Brajesh Upadhyay

    Brajesh Upadhyay Supporting Actor

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    Thanks Paul. What I was trying to say w/the latter was...should I be able to hear the HD-A1's test-tones out of the sub? Or, do I just assume it's okay w/Pete's settings w/o bothering w/test-tones and simply pop-in an actual disc to verify the LFE is indeed working? In any case, I'll have to do some experimenting tonight.
     
  15. Paul Arnette

    Paul Arnette Cinematographer

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    Brajesh,


    Yes, you should be able to hear the HD-A1's test tones out of the sub. When I could not hear the test tones out of the sub, I could not hear any LFE on an actual HD DVD. YMMY, but I doubt it.
     
  16. Brian L

    Brian L Cinematographer

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    I don't have a dog in this fight (no HD-DVD for me yet), but this thread really peaked my curiosity, as this is (or was) a very common issue with DVD-A/SACD players. In fact, in the Hi-Res player FAQ that we published, there is a question on just this subject. I thought you may find it interesting.

    Here is a link to the page in the archives with the rest of the FAQ (you will need to scroll down almost to the bottom).

    http://www.hometheaterforum.com/htf/...=107252&page=3

    Brian

    ----------------------

    Q6. I can calibrate my main speakers for equal sound levels, but the subwoofer channel is very low. Why?

    A6. This can get very complicated, and delves into issues of bass management that are beyond the scope of this FAQ, but there is usually an easy answer. Many universal and hi-rez players seem to have very low gain on the subwoofer/.1 channel. The reasons for this are not 100% understood, and there are some users of newer equipment that are not seeing the problem, but if you do see the issue, the solution is to increase the sub/.1 channel level trim using either the player’s channel trims, the receiver or pre/pro channel trims, or the subwoofer amps gain control.

    Be assured that, even if you see this problem when calibrating with test tones and an SPL meter, there is no bass that is actually missing; its just very low. When the channel gain is adjusted to provide equal levels, you will have no problem shaking the room.

    As a side note, some receivers (Denon’s in particular) have a switchable sub channel boost (0, +5, +10 or +15 dB) on the 5.1 input that addresses this issue. Also, the author has seen this problem when using an older receiver, but after a recent receiver upgrade no longer has any issues with low sub/.1 channel levels. Users of Outlaw 950 pre/pros also report no problems getting channel levels balanced. The reasons for this are not understood, but it has been speculated that newer products may have a non-switchable boost already built in.

    Suffice to say, if you don’t have the problem, great, but if you do, you will need to dial in some gain in the sub/.1 channel to set things right.
     
  17. Paul Arnette

    Paul Arnette Cinematographer

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    Brajesh,

    I just wanted to update you to let you know that I had the volume on my receiver turned down to low apparently the first time I used Pete T C's settings above. So, my comment about not getting any LFE with a setting of 120hz was incorrect. Once I turned up my receiver's volume, I heard bass with his settings, even without the -10db adjustment to the other speakers.

    That being said, the sub test tones are a lot lower than the other speakers. I originally didn't have my receiver's volume up so much because I was afraid of damaging my speakers with the loud test tones. Things sound a lot more balance when listening to the test tones if you use Pete T C's setting as is (i.e. -10db adjustment to the other speakers).

    The last thing I need to do in this area is try playing an HD DVD I am familar with, Serenity, and see if my receiver would automatically compensate for the low LFE output from the HD-A1, as my receiver does do digital processing of analog inputs. When I watch Serenity last night, I used the settings above, the bass was kickin' (technically term [​IMG]) But Serenity's LFE is mixed hot. I'll probably continue to tinker with this as I watch my other three HD DVDs and also see how it compares using SPDIF.
     
  18. Brajesh Upadhyay

    Brajesh Upadhyay Supporting Actor

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    Paul, I got it working as well. I had to set my receiver's crossover at 80Hz, which is the THX 'small speaker' recommended setting. Then, I used Pete's settings on my HD-A1. Now, I have decent LFE. Still, when using 5.1 analog, the receiver's volume level must be turned up quite a bit more than with optical-out to get something comparable loudness wise.
     
  19. Clinton McClure

    Clinton McClure Casual Enthusiast
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    I had to find a slightly different approach to fix my HD-A1 audio problem. I have it connected to a Yamaha RX-V995 via the analog inputs. I found out when I'm connected this way, the Yamaha bypasses all individual volume controls, which in turn throws my speaker calibration out the window. I had to go into the audio setup on the HD-A1 and set all speakers to large, and the crossover to 120. Then I had to play test tones (I used Video Essentials) and calibrate the audio out from the HD-A1. Since the sub level was well below everything else, I started by leaving it at 0 and turned everything else to -12dB. I played the sub test tone first and using my SPL meter, found 82dB and marked that position on the Yamaha's volume knob. I was then able to play each channel's test tone and slowly raise the gain from the HD-A1 (per channel) until I was 72dB across the board. From the point of volume reference from my SD-DVD player via digital cable, I have to turn the receiver's volume up @19dB to reach the same reference volume via analog inputs.

    Now I'm calibrated for playback from both my SD-DVD player (via digital audio) and HD-DVD player (via 5.1 analog audio) and I don't have to go in and muck about with changing settings each time I want to watch from a different source.

    I did think of something however... On most receivers, there is a DTS gain adjustment which I usually drop 10dB. The HD-A1 does not give this option and my receiver bypasses the internal settings in analog mode so I may have to do some more tinkering around with my setup when I watch a DTS track. So far I haven't been able to do any critical viewing from the HD-A1 but plan on watching Apollo 13 and Tomb Raider tomorrow.
     
  20. Paul Arnette

    Paul Arnette Cinematographer

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    Clinton,

    Which Video Essentials disc were you using? Digital Video Essentials or the older one? Which Video Essentials test tones were you using? Limited Pink Noise?

    I did some testing with a SPL meter last night. I first tested using the test tones on the Toshiba HD-A1. I left all speaker settings at default for this (size = large, distance = 0, level = 0, crossover = 120). Man are those, particularly the sub, way off. To start with, I had set my master volume on my receiver at -27, reference is supposed to be 0, which gave me approx. a 75db reading using C weight and a slow response for the speakers, but in order to match that db when the sub test tones were output, I had to up it to -9! This is close to the 19db difference you mentioned above. All of this was done with my receiver set to Multi Ch. Adjust., which is supposed to apply my speaker settings (distance, levels, etc.) to analog audio input.

    I then tested with the THX Optimizer test tones on Raiders, and the results were much more in-line. With a master volume level of 0, still setting the receiver to Multi Ch. Adjust, and leavign the Tosh speaker setting at default, I had readings around 75db. My center was -2db, my surround right was -1db, and my sub was -2db lower than 75db.

    Switching to SPDIF, I had to adust the master volume to -4 to attain a 75db, the difference between the center, surround right, and sub held constant.

    I also tested using the 5.1 pink noise tests on the Digital Video Essentials disc, but that really confused the hell out of me because it appeared that SPDIF was +7db louder than analog with the exception of the sub, which was +15db! I'm not really sure the difference between the limited and full range pink noise tests and what there supposed to read at on the SPL.

    In fact, of the three tests I did, I'm not even sure which is the most valid. I would imagine the garbage in, garbage out rule applies here as well. If the test tones are wrong, then so are the results. Do you know which of these is more reliable than the other? Is there one even more reliable?

    In the end, I think I am more confused than before I began. [​IMG] Help!
     

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