Sub Test Tone Level (should be) Fixed in RSP-1098 Upgrade

[Aussie Geoff]

Hi,

It was suggested to me by one of my sources that the DSP EPROM update in the latest RSP-1098 firmware release (plus the native EPROM code in the RSP-1068 and RSX-1067) fixed the issue that many of us RSP-1098 owners had with the Sub level in the Test Tone menu being 10 dB too low - resulting in us needed to either calibrate the sub at 85 db relative to the 75 dB for the other speakers OR use a DVD Set-up disk to set the sub level.

The problem as I am given to understand it - was that the sub test tone level was set at 30 dB below reference - as for the other test tones. It's just that reference for speakers is 105 dB (hence 75 db) while reference for the .1 LFE channel is 115 db - hence the old sub test tone should have given 85 db, making it 10 dB too soft when calibrated to 75 db. The sub test one is now set at a level of 40 db below the 115 db reference, making the 75 db calibration accurate (I hope that’s clear....)

Well - today I tried and (for me at least) it's fixed. The RSP-1098's test tone for the sub calibrates at the same relative level as the speakers.

Can some others who have done the upgrade please check to see if we have a consistent fix?

If (as I suspect and Rotel hopes) we are all fixed, then it's a good thing to remember for those using the "set the sub tone at 85 db" fix we had before - this will give WAY too loud bass now

Will also help prevent some (understandably) excited new RSP-1098 owners reading all those old posts to learn what to do right and calibrating their subs wrongly given the fix...

Enjoy

Geoff

[Sithlord10]

Hey Geoff. I tried 3 different sources to calibrate my speakers. One was the test tones on the 1098 the other was the Dobly Lab disc called Explore our World you can buy from their site and finally the Sound and Vision Home Theatre Tune Up disc. Well using the 1098s test tones matched the Dolby disc but the levels of my speakers went from mains (-1) to (+7) Rears (-1) to (+6) . Using the Sound and Vision disc the levels went back to what I had initially. Now I'm using a sound level meter set to 70 (0 on the meter) so any thing above the 0 is 70 something. I don't know why the 1098 test tones are way off because if I left them that way it's way too loud for my set listening level which is 68 on the volume on the 1098. I set the volume to 68 when running the tones for each source. My question is how do I know whats the right test tone? I even tried the THX Optimzer and that was very different than all of them. Funny thing was that the sub setting for all sources was correct. So what test disc to people use to set their speakers to 75db? I'm sticking to using the Sound and Vision as it sounds right to me. The others are just too high or maybe my unit is suffering from some fault who knows anything is possible with my 1098 :roll:

[Aussie Geoff]

Sithlord10,

Well at least the sub test tone is fixed

Anyway - re the calibration. It is usually best to treat the front left and right and sub as being 0 dB on the test tones. All other settings (centre etc) are relative to that. Note: Different DVD set-up disks are mastered for -30 db, -27 db and -20 dB etc to reference making it very confusing to switch between them as you need to match the volume level to the one intended for the DVD. I suspect this is why you are achieving the differing results.

Now the Rotel is designed for the post popular -30 dB test tones, giving a 75 dB set-up level So - using the Rotel test tones you:

• Enter the TEST TONES menu
• Set the front left, right and sub to 0 dB
• Use the RSP-1098's volume control to increase or decrease the main volume to get the front left and right set at 75 dB
• Use the sub amps volume control to set that at 75 db (leaving the Rotel test tone level at 0 db
• Leaving the RSP-1098 volume control unchanged, adjust the RSP-1098's relative levels up and down (e.g. -2 dB or + 3dB) to match the centre, and rears etc to be 75 db.
• You have achieved the most important calibration - all your speakers are set to a common master level at the same volume control level
• Adjusting your volume will maintain a seamless sound balance across all speakers. The actual volume you play at is up to you!

However if you are concerned about reference (I know your old Denon AVR-1S did volume relative to reference as do many receivers and processors) - then remember the volume setting on the RSP-1098 that corresponded to 75 dB on the test tones (something like 71 or 74 or whatever) this will be reference level (since you are playing a test tone that was 30 dB below reference). Now if you want to play at (say) 15 db below reference level - just take 15 off the reference level volume control (e.g. 74 - 15 = 59).

Note: Edited Post - Based on some PMs received - It is this last point that has confused a number of Rotel RSP-1098 users – because the volume on the test tones is (depending on room size and speaker efficiency) typically somewhere between 70 and 80, many people have set their volume to 75 and tried to adjust the speaker levels up or down to get 75 dB at 75 – which gives the wrong calibration.

Personally - once calibrated - I just ignore reference and remember the RSP-1098 volume that sounds right for DVDs etc – it’s way easier than all that mental arithmetic and what I used to do anyway with my Denon (I’d remember -15 dB was loud and -10 dB VERY loud).

Geoff

[Sithlord10]

Thanks Geoff I've never set it up like that before. After following your instructions I found that my bass level had dropped. It's clear that mine is still 10db lower than the rest of the channels. I set the spl to 80 and turned up the sub amp until it reached 85 and it's back to normal. The channel levels are as follows:

FL:0, C:-2, FR:0, RR:-2, LR:-2, Sub:0

When I purchased the SVS B4+ they said to set the volume of the sub amp to max and then adjust the volume on the receiver unitl it reaches 75db. This was how I had it before but I have since tried your method and I'm very satisfied with the result. I know many HT owners out there run their Subs hot sometimes 8db over reference. I currently have mine about 4db. Thank you for time to explain the setup as I've never been 100% sure of how you setup your speakers. I will be calling International Dynamics and either they fix my current unit or I'm going to ask for a replacement. I just don't feel comfortable having mine constantly being opened and fiddled with and touched. Again thank you for your help it's much appreciated. I hope your enjoying DolbyPL11x.

[Adz]

Hi Geoff,

2 follow-up questions,
You said in your previous post, "Use the RSP-1098's volume control to increase or decrease the main volume to get the front left and right set at 75 dB". Doesn't that assume the left and right are perfectly in-sync already? Meaning, if 65 on the volume control gives me 75 db reading on my left speaker that doesn't necessarily always follow that the right speaker will give the same 75 db reading.

What's the sonic difference either "Use the sub amps volume control to set that at 75 db (leaving the Rotel test tone level at 0 db)" or treating the sub as the other speakers in the system and adjusting the test tone level directly?




Adz

[Aussie Geoff]

sithlord10,

Glad you like the set-up technique - I got it off an old thread in http://www.hometheaterforum.com a couple of years ago and have found it invaluable – it works with any test tone source – you just need to know the level for that source and you can calibrate to reference.

The SVS “set the sub amp to max” approach is an interesting idea - however it will amplify any noise / hum on the signal etc more than necessary so I avoid it (and I have read some threads expressing concern about the hum levels etc with this and the tendency for the sub to make very loud noises when presented with soft mains clicks etc). Processors and Receivers are quite comfortable at 0 dB line out on the sub. They even do OK at +3 dB (twice the power). Its people that run at +8 or 10 dB that run a clipping risk (+10 is twice as loud but 10 times the power).

Re your bass level - interesting. I suspect you and whmacs have a early build RSP-1098 and MAY benefit from / require a new DSP board and Cirrus Processor. We are now entering the realm of speculation but follow this logic:

• The Cirrus DSP processor in the RSP-1098 is essentially a computer - processing signals at 700 MIPS (like a Pentium III Processor on PC).
• Such processors have on board microcode etc that (almost always) goes through manufacturer revisions over time as people find faults with the processor under certain circumstances while coding / building / testing devices using the chip.
• It is common for firmware writers to check the build version of processors like DSP chips and selectively implement work arounds depending on the build version.
• There can also be interactions between the DSP chip and the design of the board and circuitry driving it and processing its output that can lead to manufacturer revisions.
• The Rotel RSP-1098 was one of the first (possibly the first) Processor to use the latest generation Cirrus Chip.
• One could easily imagine a situation where early build RSP-1098's have early build Cirrus DPS chips and or DSP circuit boards.
• It is interesting to see the similarities between your issues and whmacs re the 7 vs 5 channel – most likely to be DSP related issues given the same firmware is running that works correctly on other RSP-1098s.

Anyway – food for thought – but I’d be having a serious conversation with International Dynamics about trying a new DSP board which I wouldn’t mind betting fixes the problems you are having

LATE EDIT - Of course as the postings tonight by olaf are worked through - maybe there is a more widespread 7.1 EX issue impacting you and your DSP is fine (but time will tell) - life is complex....

Geoff

[DrBoom]

Oh, so now there actually WAS a problem, though I was told they never succeeded in replicating what I said earlier.
Rotel informed me that they couldn't find any problems with the sub level.
I'll have to try it asap then, I've recently upgraded mine to 2.1.1 too but haven't calibrated since.

[skipm]

Just checked my speakers using the internal test tones and I'm happy to report that it does indeed look like Rotel has corrected the sub test tone issue.

Good going Rotel!

-Skip

[DrBoom]

Hate to rain on your parade, but mine still does it
I tried it last night, and it still isn't quite the same as with an external calibration DVD.
Oh well, I don't use my sub that much anyway anymore since I got the 804's.
So I just calibrate it with the HT Tune up dvd, for both Dolby and DTS.
For stereo it stays off until I can afford one that blends better with my mains, something along the lines of a B&W ASW800/850 or a REL Stadium.

[Aussie Geoff]

Dr Boom,

By "still isn't quite the same" so you mean a 10 dB difference or a smaller difference between the DVD test disk and the internal tones? Small differences are normal due to different frequency profiles etc on bass test tones interacting with the sub and the room.

The easy test is (no change to sub level) = before the RSP-1098 internal test tone when calibrated right would play the speakers at 75 dB and the sub and 85 dB. Now, without changing any level setting - they should be basically the same within about 3 dB.

Geoff