1098 and SPL

[NHT]

Ok guys. I got my Radio Shack digital spl ready. This is my first time calibrating with one so could someone please guide me on exactly what to do. I have the Rotel 1098. I also have the Avia disk handy too. Thanks

[Aussie Geoff]

Try this

NHT,

Here is a short form answer using the RSP-1098 test tones.

• Set all your speakers to SMALL etc as per the other’s recommendations. 80 Hz crossover for centre and rears, your choice of 60 or 80 for the front left and right.
• Use the 1098 DELAY SETUP menu to set the distances of ALL speakers including the subwoofer from a central listening position
• Set your SPL meter to C weighting and slow (I don't know if your model has a range but if it does pick the one with 70-80 dB in it
• Sit in a central listening position in front of the TV / SCREEN etc
• Bring up the 1098 TEST TONE Menu and the use the + and - keys on the remote to set all speaker levels at 0 db
• Use the up and down keys to get to Front LEFT speaker (you will be hearing a continuous test tone from each speaker you select
• Point the SPL meter at the speaker (keeping it a little away from your body)
• Adjust the volume upwards using the 1098 VOLUME CONTROL on the remote until the display on the SPL meter shows 75 db (or close to it (in the range 74.5 to 75.5) – The level on the TEST TONE menu will still be showing 0 db
• Leaving the VOLUME control untouched, use the remotes down key to move to the CENTRE speaker. Note use the + or – key to adjust the volume of this on the test tone menu until it is also reading close to 75 db on the SPL meter. Typically this is a small adjustment like +2 dB
• Do the same for the RIGHT speaker. This will often be 0 db or close to the Left speaker as they are usually very similar.
• Now do this for your rear speakers, remembering to point the microphone at them while staying in the same position. Typically rear speakers are a little less efficient than the mains so they too end up with a small positive level adjustment like +3 dB to bring them up to the same relative volume as the mains.
• The aim here is to get all speakers playing at the same relative volume level.
• Now, leaving your sub’s level on the RSP-1098 set to 0 db and without changing the volume, measure the subs SPL.
• This is where it gets tricky – most RSP-1098s test tones are too low by 10 db, requiring a 85 db setting to be the same volume as the speakers, but there seem to be a few which are right. I am going to assume that yours are too low like most peoples.
• Read the sub SPL level and then, leaving the SPL meter where you sat, go over to the actual subwoofer and adjust its gain up or down as needed yo play 85 db on the test tone (for example if the SPL on the sub is 80 you will need to turn the subs volume up on the sub.)
• You may have to do this sub adjustment several times using fine adjustments of the gain or volume control on the sub to get it right (remember measure from your listening position).
• Exit the 1098’s MENUs and play something – it should sound great….

If you seem to have way too much bass – then you are one of the lucky people with accurate sub test tones – just redo the sub calibration test but measure for a 75 dB SPL instead of the 85 db.

You can be sure you are right by playing the test tones on the AVIA DVD test disk, adjusting the 1098 volume control on the test tones for the front left to make it 75 db or 85 db, and then confirming that all speakers (including the sub) play at equal levels with the settngs you have come up with using the test tones!

Geoff

[PiDD]

It's pretty simple.

Start the Avia speaker test. Turn your volume up so the SPL reads about 75. Now cycle through the speakers and ensure they are all playing at the same level... adj the speakers up or down.

If the RS didgital meter is like the analog one dial your sub woofer +10db .. so adj it to 85. The RS meter doesnt measure the low freq that well.

If you want to mess with the sub and placement I have some test tones and an excel spreadsheet that compensates for the RS meter and graphs the results. LEt me know if you want it and I can make it available.

[Sithlord]

SPL Meter

Geoff in regards to the use of the spl meter shouldn't you hold the meter so it point towards the roof at ear level and not point it towards each speaker? I'm sure I read that somewhere correct me if I'm wrong.

NHT what Geoff told you is great and helped me out when I was setting up my gear and after it was done it sounded fantatsic. This method will insure all your speakers are at the correct volume which is vital for a balanced HT. Good work Geoff. :T

[Aussie Geoff]

Silthord,

SPL meter shouldn't you hold the meter so it point towards the roof at ear level and not point it towards each speaker? I'm sure I read that somewhere correct me if I'm wrong.

This holds true for some proffessional SPL meters with omidirectional microphones - however the Radio Shack and Dick Smith style are not that good and (at least the ones I've tried) are quite directional, so I find you get better results by pointing the microphone at each speaker from the same position - on mine it varies the sound reading sby up to 3 DB. In (rough) order I've found:
>> Worst result is to always hold straight ahead (leads to rear speakers being set too high) as the sound from the rears shots past the microphone (most is absorbed by the body anyway).
>> Upright technique is quite good if held well away from the body but tends to take a lower reading of everyting as most sound travels over the top of the microphone.
>> Pointing give the most accurate.

Geoff

[Sithlord]

Thanks for that. I was always told to hold the spl upright and at ear level when taking measurements. I've got the radio shack analogue spl meter so I will try your way and see what I get. Sorry to change the subject but have you heard the Starwars trilogy yet?

[Aussie Geoff]

Silthord,

Yes - I have the Starwars DVDs - they've come up very well for 25-30 year old movies.... You can hear some of the special effects sound have been redone (e.g. Light Sabre's etc) However the music etc is still older style recording. So the sound is not a patch on Volume I and II... However they are "must haves" for any collection - amazing films for their time...

NHT

Now how did you go with that full system calibrationusing the SPL meter? Unless there is something wrong with your RSP-1098 that should have your system sounding way better....

Geoff

[NHT]

I calibrated last night and the sound was a bit better. However, it is by no means a dramatic improvement over my 1055 that I was opting for. The sound is just thin and harsh. Maybe it just needs time to break in because I have exhausted all efforts to get it up to snuff.

[aarsoe]

I like to add one other thing to Geoffs otherwise good instruction.
If possible use a tripod for a camera so that you will never be in the way of the sound waves - This applies even if you point the meter towards the ceiling.... So when adjusting front speakers and center you stand behind to read the value's, and on the rear speakers you would turn the meter 180 degree's.
Remember to mount the tripod in your favorite seating position, at ear hight, and you should also write down the values and repeat the procedure for the "spouse" position and see if there are any differencies.. If so, you could try a compromise setting..