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Why the Bass Problem?

post #1 of 20
Thread Starter 
What is the reason for the -10db drop in the LFE channel on SACD when you use the 6 channel analog connections on a receiver?

I have a Sony SACD player, and wanted to start buying SACD's, but the first SACD I purchased I noticed almost no bass coming through the sub. Doing research, I found this was a widespread problem.

This "defect" essentially killed the SACD format for me. It is just too much of a pain to recalibrate my settings everytime I want to listen to a SACD, especially if you're going from CD's to SACD's during a single sitting.

Is there an easier way, or do newer receivers compensate for this? It's a shame, because I was really excited about the SACD format when it came out, and I'm sure this one defect really hurt the format for a lot of people.
post #2 of 20
If you use a player/receiver/pre-pro combo that includes HDMI and/or firewire, then I believe the problem is resolved. I have an analogue output setup and I solved my bass problem with a disc from Pentatone (an SACD classical sampler with test tones specific for SACD). Since then, I've had no trouble with SACD or DVD-A (I have a separate player for CD playback, so I haven't noticed a problem with CDs--I could try a few CDs on my hi-res audio player and get back to you if you'd like).
post #3 of 20
The reason is most use a home theater setup to listen to surround sound music. Movies have the LFE at -10dB and the receiver or pre/pro adds the +10dB back. So this is an attempt to make SACDs work within this setup.
post #4 of 20
Thread Starter 
Craig,

Do all receivers using direct analog connections have to boost the LFE channel to bring the bass to a normal setting?

What I don't understand is Sony designed SACD to be almost exclusively used as an "analog out" device in order to provide extra copyright security. There are a few proprietary digital links, but for the most part SACD was to designed to be exclusively "analog out".

Knowing this, shouldn't Sony have expected this was going to be an issue, since the only way to use the surround features on the disc would be through the 6 channel direct analog inputs on a receiver?

It looks like to me Sony easily could have made the LFE channel on the SACD player adjustable or "properly" boosted in the first place so these types of connections would sound correct for most consumers. For me to make this adjustment on my receiver, I have to go deep into various on-screen menus to make changes, and then when I am done playing a SACD, I have to change the setting back so I can use my receiver to play a DVD or standard CD.

I do like the sound quality of SACD, it has a rich smoothness to it, but for this much trouble I might as well just stick with vinyl.
post #5 of 20
Quote:
Originally Posted by jacob_coulter View Post

What is the reason for the -10db drop in the LFE channel on SACD when you use the 6 channel analog connections on a receiver?

Because you haven't calibrated the system correctly. The LFE is deliberately recorded "low" to force you to turn it up - then it can make a really loud noise if necessary. (But see below).

Quote:


I have a Sony SACD player, and wanted to start buying SACD's, but the first SACD I purchased I noticed almost no bass coming through the sub. Doing research, I found this was a widespread problem.

This "defect" essentially killed the SACD format for me. It is just too much of a pain to recalibrate my settings everytime I want to listen to a SACD, especially if you're going from CD's to SACD's during a single sitting.

This shouldn't be necessary. It's not the format's problem at all. In fact, on SACD the LFE isn't actually recorded 10dB low, it's that the player is lowering it 10dB to make it the normal LFE level (to match all other formats). If you were using the multichannel input for Dolby Digital, DTS, or DVD-Audio, the receiver would be requiring the +10dB/+15dB boost. So an SACD player, or a multi-format player supporting SACD, adjusts its output to match those.

Presumably, you are using the multichannel inputs for SACD, and only for SACD. It's the multichannel input that needs adjustment. You just need to turn up the multichannel subwoofer input by 10dB or 15dB. Don't adjust your subwoofer output level, as that will affect all the other sources. It should be set-and-forget.

Also, make sure bass management is enabled in the player.

Its possible you may have a deficient receiver that doesn't give you independent control of the multichannel inputs, or you might have a deficient player without bass management. Then you'll have a problem.
post #6 of 20
Actually, once you know what the problem is, and if you have a receiver that allows different settings for different inputs, the problem is easy to resolve.

For example, I happen to have a Denon receiver. In the setup menu, it specifically asks whether or not I want to add a boost (up to +15) for the external inputs (which I do). Playing SACDs works fine.
post #7 of 20
I personally have noticed a loss of LFE in Mulitch SACD via HDMI with my PS3. Same disc, in 2ch mode gives good deep bass. switch to the Multich layer and maintain the same MV, the bass is significantly less than the 2ch mode.
post #8 of 20
Thread Starter 
I was under the impression that the 6 channel analog inputs were "pure" in that there was no adjustments you could make because it was a raw, untouched signal, the receiver just acted purely as a direct output amplifier.

My receiver is a Harman Kardon 520, I'll look to see if you can adjust the inputs, I thought I could only control the outputs.

Thanks everyone for the advice, maybe I won't give up on SACD!
post #9 of 20
You're basically right, Jacob, but the manufacturers are allowing for the fact that some channel level adjustment may be required, particularly for the subwoofer channel. There's still a pure-analogue path, they just allow a different set of final amplifier levels to be selected for that input.

In terms of user interface, some receivers have a separate set of level controls for EXT IN, which are used in place of the normal set, and some treat it as an extra input adjustment which is added to the standard output set. But I suspect the underlying implementation is the same.

If it was totally "pure", the master volume control wouldn't work.
post #10 of 20
Thread Starter 
Looking through my manual, it doesn't appear there is a way to raise the input values, only the output values. I'll look deeper, but I don't see any provisions for this type of adjustment.

So in order to get the bass to a "normal" level, I will need to increase my LFE channel output by +10db. I will play around with it, but I think this means I will have to adjust my channel settings each time I play an SACD, then change them back when I want to listen to a regular CD or DVD, otherwise the subwoofer will be 10db too high whenever I listen to any other source.

I really think Sony should have put a channel adjustment on the SACD player itself. This would have been a simple solution to this issue. I can't be the only person who has issues with this setup. Sony should have had the foresight to see this was going to be a problem unless you had a real high-end receiver.
post #11 of 20
My receiver (an Integra DTR 6.4) applies bass management to the analogue MCH input (so I don't use the bass management of the player) BUT the level setting controls do NOT work on the receiver's MCH input--so I have to set the player's subwoofer level to the appropriate setting. However, that only comes into play when I use the player's analogue output (whenever I use the digital output--movies, mainly--the receiver's level settings are active, so it doesn't cause me any interference). However your system works, you have identified one of the major obstacles for mainstream MCH hi-res audio adoption. It SHOULD be as simple as it is with standard DVD.
post #12 of 20
Quote:
Originally Posted by jacob_coulter View Post

So in order to get the bass to a "normal" level, I will need to increase my LFE channel output by +10db.

You mean subwoofer output. Please don't get terminology confused.
Quote:
I really think Sony should have put a channel adjustment on the SACD player itself.

Do they really not have this? I've never seen a device with multichannel output that doesn't have level calibration. What player is it?

If nothing else, you should be able to turn all the other channels down to restore balance, although it will mean turning your master volume up higher.
post #13 of 20
Quote:
Originally Posted by jacob_coulter View Post

Looking through my manual, it doesn't appear there is a way to raise the input values, only the output values. I'll look deeper, but I don't see any provisions for this type of adjustment.

Harman Kardon AVR-520, right? Looking at the online manual, page 33, it suggests that there's one lot of level adjustment done directly via buttons, and then another lot accessed via CHANNEL ADJUST on the on-screen menu. That second lot is claimed to be settable for "each digital and analogue surround mode". Maybe that includes the 6-Channel Direct Input.
post #14 of 20
Quote:
Originally Posted by KMO View Post

Harman Kardon AVR-520, right? Looking at the online manual, page 33, it suggests that there's one lot of level adjustment done directly via buttons, and then another lot accessed via CHANNEL ADJUST on the on-screen menu. That second lot is claimed to be settable for "each digital and analogue surround mode". Maybe that includes the 6-Channel Direct Input.

I believe that function is similar to my receiver--I can set the levels in the main set up area (they are permanent unless I clear them or the power is out for an extended period)--but I can also "adjust on the fly'' for each input (though that is lost if the receiver is turned off, for sure, or perhaps even if I change inputs--I've not tried it). In any case, level settings are NOT available for me on the MCH input (I get a scrolling message saying that function is not available on the receiver's display). They may be available on the HKs though. I know some Pioneer receivers allow level settings on the MCH analogue inputs BUT don't allow anything else (opposite of mine). It's really too bad they couldn't (or rather, wouldn't) work out a standard before releasing these products.
post #15 of 20
Quote:
Originally Posted by KMO View Post

You mean subwoofer output. Please don't get terminology confused.


Actually the correct terminology would be LFE INPUT, as the boost should be happening at that stages on the receiving end.
post #16 of 20
Quote:
Originally Posted by thehun View Post

Actually the correct terminology would be LFE INPUT

Not if your using BM in the player. It becomes a SW when LFE is combined with the low bass from the other channels. It can only be LFE when all channel are set to large...

Mark
post #17 of 20
I guess one can make a distinctiction like that, but it is the LFE part of the combined SW output that remains low by design.
post #18 of 20
The combined SW output has to be low too, to incorporate the LFE. Whichever device is summing LFE and main channel bass has to be aware of the 10dB difference, and either raise the LFE to match the main bass or lower the main bass to match the LFE. The latter is the norm in an external decoder.
post #19 of 20
Quote:
Originally Posted by jacob_coulter View Post

What is the reason for the -10db drop in the LFE channel on SACD when you use the 6 channel analog connections on a receiver?

I have a Sony SACD player, and wanted to start buying SACD's, but the first SACD I purchased I noticed almost no bass coming through the sub. Doing research, I found this was a widespread problem.

This "defect" essentially killed the SACD format for me. It is just too much of a pain to recalibrate my settings everytime I want to listen to a SACD, especially if you're going from CD's to SACD's during a single sitting.

Is there an easier way, or do newer receivers compensate for this? It's a shame, because I was really excited about the SACD format when it came out, and I'm sure this one defect really hurt the format for a lot of people.

Simple solution - drop the LFE channel altogether as redundant audio info and redundant solution to bass managment already (most likely) implemented in your amp.
post #20 of 20
Quote:
Originally Posted by KMO View Post

The combined SW output has to be low too, to incorporate the LFE. Whichever device is summing LFE and main channel bass has to be aware of the 10dB difference, and either raise the LFE to match the main bass or lower the main bass to match the LFE. The latter is the norm in an external decoder.


Well normally you need a +10db boost if no BM is used on the player, if it is used, then you need +15db, since as you pointed out the player lowers the total output even further. I have no idea how the receiver sort this out, but at the end it has to mantain the 10db offset[boost] for the LFE to be balanced, compared to the redirected bass, and other channels as well.
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