What is the industry standard for sub offset when using analogue in...?

[Basil Plumley]

I have a Sony BD-P760 connected to an Arcam AVR300 via the 7.1 channel analogue inputs...the player decodes just about every format internally - including DTS HD MA ES found on the LOTR discs...but I'm getting the age old problem of lack of bass.

The Arcam has a setting in the subwoofer setup to allow you to add 10dB to the LFE channel when using the analogue inputs, but when flicking between it on and off whilst running the test tone on the Sony, it barely moves the needle on my SPL metre - so it's barely giving 1 or 2dB increase when it's supposed to give 10...

The only way I can counter it is to turn all the channels down to 10dB below what the sub is set at on the Sony (so in effect, all of them are -10 or more) and leave the +10 on on the Arcam...but surely this is giving me an overall +20dB increase in the LFE channel - isn't it...? Plus this means that to get the sound at anywhere near normal listening levels I have to run the volume at 90%...

Any help would be greatly appreciated...

of Epsom...

 

[Bossk128]

I suffered a similar problem here.

I never got round to fixing it and so I'm only listening to Blu Rays via optical. I suspect my +10dB for some reason is not working. My idea was to upgrade the firmware (or reset to factory defaults if firmware was current), and see if that helps.

Good luck!

 

[Passingbat]

You actually need a +15db boost --- the 10db handles the required LFE boost (due to it being -10db down on the BR disc), but you also need 5db for the base management if you're running your speakers as small.

This article explains it way better than I can:

How To Set up a Blu-ray Player Using Multi-Channel Analog Outputs... And Why: BigPictureBigSound

 

[MrNPG]

Yep, I use a +15db boost for my sub. I have it increased by 10db on my Denon AVR (the max boost) plus a 5db boost on my Oppo BD player = a 15db total boost.

 

[Basil Plumley]

I was contemplating using the optical digital input - but I was so impressed by the sound through the multichannel inputs (except for the lack of bass) that I thought I would give it a go. When I've used the 6 channel in on other amps or receivers, there's always been something lacking as well as the bass - not so with the Arcam - I feel as though I am now actually getting "lossless" sound...watched Solomon Kane last night having added another 5dB to the LFE as well as the 10 already added and the place rocked - what amazes me though is the fact that the increase in LFE level doesn't actually show up when running the test tone from the Sony on a SPL but it's certainly there it actual bass terms...

I have a Harmony remote that enebles to add add additional commands to the on/off commands - I have programmed it to turn the sub up 5dB on switching on the Blu-ray and turning it down 5 when switching it off...takes a while to start up but by the time I've got the screen down and the PJ is fired up, it's ready to go...

 

[Bossk128]

If there is an additional +5 on the subwoofer, doesn't this mean all the other sound sources are then out of whack?

And do you need the +5 if the speakers are set at large? I though having small speakers meant that for those channels, anything lower than the crossover was redirected to the sub (so in my setup, 2 large at the front, two small surrounds, F and L bass comes from the front two, bass directed to the rears is redirected to the sub, and of course the .1 comes from the sub too). Why is there a need for another 5dB?

I'll tell you what, I'll go read that link dicklodge posted. Maybe that'll answer it

 

[Basil Plumley]

Yep, I use a +15db boost for my sub. I have it increased by 10db on my Denon AVR (the max boost) plus a 5db boost on my Oppo BD player = a 15db total boost.

The problem I see there is that you aren't supposed to add any additional bass from the player - reading the link, I think it means that the boost has to be done at the amp because the analogue carrier simply doesn't have the capability to carry it...

One day, I'll come into line with the rest of the world and get an amp that has HDMI...

 

[Bossk128]

The problem I see there is that you aren't supposed to add any additional bass from the player - reading the link, I think it means that the boost has to be done at the amp because the analogue carrier simply doesn't have the capability to carry it...

One day, I'll come into line with the rest of the world and get an amp that has HDMI...

And then when you start reading up about jitter on audio over HDMI, you'll wonder why we even bother!!!!

 

[rallychief]

I think this is a standard problem, when using a Sony 550, I had to do the same, that is reduce all channels by 10 db, then was running the volume control on my Legacy proccessor ( normally in the -20 to -25 region with other sources) in the 0db to +5 region, not a good thing, especially if you forget when you change sources.

Hence why I am now running a Denon 3800, one of only a few machines that addresses this problem, I do miss the load times, and glitch free play, on that cheapo Sony though.

 

[Basil Plumley]

I think this is a standard problem, when using a Sony 550, I had to do the same, that is reduce all channels by 10 db, then was running the volume control on my Legacy proccessor ( normally in the -20 to -25 region with other sources) in the 0db to +5 region, not a good thing, especially if you forget when you change sources.

Hence why I am now running a Denon 3800, one of only a few machines that addresses this problem, I do miss the load times, and glitch free play, on that cheapo Sony though.

So what other options does the Denon 3800 give you? I've now given up on this and am going to use optical digital for the time being...

 

[rallychief]

Hi Basil, the 3800 does little if anything picture wise, where it excels is in the superb analogue 7.1 audio output section, which is head and shoulders above the Sony, in SQ via my Integra RDC7 proccessor, add to that the facility to add 10 db of bass enhancement at source, and change crossover frequencies, it's the tool for the job.

However, the much cheaper Sony, loads faster is profile 2.0 for BD live, all depends what you want, for me SQ is king

 

[Basil Plumley]

So what you're saying is that the 3800 adds crossover points to the equation...?
If you measure the sound via an SPL, does the bass actually register on the metre?

I had an RDC7 along with the power amp - and sold it to buy an Onkyo 875...

 

[Passingbat]

I have a feeling that I read somewhere, that the test tones from the Sony don't work on the LFE channel. My memory may be letting me down over this as it was a while ago when I looked into going the analogue in route with my Yammy 1500.

If you say you're getting the base (when playing the disc) now you've added the extra 5db is it a problem that the test tone doesn't produce it?

The lack of crossover adjustment on the Sony 550 level analogue out players has always been a limitation. It doesn't help that they don't seem to say what they've actually set it at. Someone said it was 100HZ but I don't know if that is an accurate statment.

 

[rallychief]

Hi Basil, yes the 3800, has a variable crossover within the audio setup, don't know re the sub registering on a meter, as I use the mk 1 earhole. It is audible though, would LFE rgister on the meter the same as the rest of the speakers, as it cannot reproduce the white noise signal?.

I assume you swopped to the Onkyo to get the HDMi inputs ? I deffo wouldn't have done that.

 

[Basil Plumley]

I've got a couple of weeks off coming up so I'll dedicate about 10 days of that to getting this right...

 

[IWC Dopplel]

I run a Denon 3800 with 60HZ crossover and find that using small all round works best in my room. I use a db meter and measure using dbC and simply set with test tones from the player.

I have tried 40 and prefer 60. When I ran with an AV8 and DVD player I set the xover at 50 after a lot of experimentation.

I have yet to find a HDMI processor to impress with SQ. If I had £5-10k burning a hole in my pocket I would try an AV888, ADA and Anthem

 

[Ian_S]

A small hint...

A player cannot fix the 10-15db correction required.

The whole reason the LFE is reduced is because the standard RCA connection is supposed to support only a 2V signal, LFE can go up to 6V. If a player lets you boost the LFE, then you stand a good chance of sending a clipped signal. This is why some players only let you reduce channels so that LFE won't get clipped.

The receiver is supposed to fix this. If it can't add a 10db boost or 15 if required, then really you will struggle to get decent analogue audio bass. So get a new receiver or stick with a legacy digital input where the bass is properly controlled. (A major reason why DTS re-encode is such a good idea.)

Now some amps may accept bigger signals than 2V, but this is very much model specific and not to be relied upon, and is probably best used with an SPL to make up any difference required between 10db and 15db boost, as while a reasonable no. of receivers have the 10db boost option, far fewer have a 15db one.

Be warned.

 

[Basil Plumley]

This is why some players only let you reduce channels so that LFE won't get clipped.

I don't think I've come accross a player yet that actually lets you increase the volume...and now I know why!

I'd read that it wasn't a good idea to try and boost the LFE signal by anything at the player end and the link posted above shows that...I am managing to boost the LFE by 15dB by using the 10dB boost the Arcam gives you and then manually adding another 5dB on the channel levels on the amp - but it still appears bass light and compeltley 100% fails to register on an SPL - but there is bass there...wondering if I need to adjuat the crossover at the sub or something...? At the moment I have it set to 80hz as my speakers (including the sub) are THX certified...I'm assuming the crossover set on the amp when setting the speakers up initially goes out the window when using the player to decode...?

 

[Ian_S]

Correct, the player sets the crossover.

I would recommend getting a test disc to use for calibration. Built in tones can be fraught with all sorts of bugs.

For the Arcam's it's the DVD-A 10db boost you need and leave the DTS setting well alone.

 

[Basil Plumley]

Correct, the player sets the crossover.

I would recommend getting a test disc to use for calibration. Built in tones can be fraught with all sorts of bugs.

For the Arcam's it's the DVD-A 10db boost you need and leave the DTS setting well alone.

Problem being, you can't play a test disc when setting the speakers on the Sony...I suppose you could always run the disc, note the levels then adjust them in the set up menu on the player and keep going back and forth...good job I've got that couple of weeks off!

Out of interest, does anybody know what the volume should be at for reference level on the Arcam...? Read somewhere it is 0 but that's max volume...

 

[Ian_S]

I am managing to boost the LFE by 15dB by using the 10dB boost the Arcam gives you and then manually adding another 5dB on the channel levels on the amp - but it still appears bass light and compeltley 100% fails to register on an SPL - but there is bass there...

If this sounds fine on the Arcam for normal digital sources then this will be your problem.

The Arcam level control affects both analogue and digital. IF the bass sounds ok for DD & DTS digital sources, then this implies you will have turned down the actual sub volume control to compensate for the +5db you've added to LFE on the Arcam. By adding +5db to LFE, digital sources should be way to hot in the bass dept.

If digital sources are fine. and if that's what you've done, you've effectively negated the 5db boost.

What you should do is calibrate the Arcam for it's digital sources, enable the +10db DVD-A boost for analogue and then on the player, using an SPL, reduce the other channels relative to the LFE channel until it's in balance. Again I would use a test disc rather than player or built in Arcam tones.

 

[Basil Plumley]

If this sounds fine on the Arcam for normal digital sources then this will be your problem.

The Arcam level control affects both analogue and digital. IF the bass sounds ok for DD & DTS digital sources, then this implies you will have turned down the actual sub volume control to compensate for the +5db you've added to LFE on the Arcam. By adding +5db to LFE, digital sources should be way to hot in the bass dept.

If digital sources are fine. and if that's what you've done, you've effectively negated the 5db boost.

What you should do is calibrate the Arcam for it's digital sources, enable the +10db DVD-A boost for analogue and then on the player, using an SPL, reduce the other channels relative to the LFE channel until it's in balance. Again I would use a test disc rather than player or built in Arcam tones.

Many thanks for your help - I shall give it a go. I'm thinking of using a THX demo disc with the optimode setup on it...would this suffice you reckon?

 

[Basil Plumley]

Just a quick update - using Ians' advice, I had a play today using the aforementioned THX demo disc - and in particular the optimode section...

I'm certainly getting a reading on the SPL now from the LFE channel, though it's nowhere as high as the other 7 channels...bringing those channels down to the same level means that I have to run the amp very loud therefore raising the noise floor...
I'm nearly there and I think I will eventually get there in the end will a little trial and error...then I've got the XE1 HD DVD player to do...