How to use test tones to calibrate

racer4551

Well i ran all the tones in the 0,45,90,135,180 phase positions and the most stable was the 180 position.Here is updated graph,still ugly...........................

racer4551

Still unsure whats happening in the 80hrtz to 50 htz area pretty big dip there....................gonna try moving the sub out beside the left front main tommorro then recheck everything.

pjdami

Racer, just noticed your system on your sig. Question for you. why are you using the ICBM if you have a Rotel RSP-1066? The Rotel should be able to handle the crossover duties right? Just curious. I had the RSX-1055 for a while last year and am familiar with the menus.

racer4551

I have tried it both ways ,using rotels bass management without the icbm and with the icbm,even though i have not tried using rotels bass management with the lsi's,i find that with the icbm the sub response is a lot better,blends with the other speakers more,it seemed to my ears that sub response was weak using rotels bass management?Also you are limited only to one crossover setting for all speakers in the rotel setup and when it was purchased i thought i needed the individual crossover settings to setup properly with the different surround speakers i had at that time.I am thinking about using the rotels bass management before i move the sub just to see how it effects the freq. response .

racer4551

Well i tried using the rotel's bass management and it didnt make any difference at all to the curve.I have this big dip i am wondering about from the test tone of 79.4 to 56.2 the level drops on average of10 to 12 spl,could this be sub placement issues?

Tour2ma

Have you tried changing the cross-over point? If not, run sweeps with it at 100 and at 60...

pjdami

could this be sub placement issues?

Could very well be. Try a couple of quick sweeps at different xovers like Tour said and then time to move it to the other side of the soundstage if you still have the null.

racer4551

Well i moved the sub to the right front corner,recalibrated sub level(sub is 10db higher than other speakers) sub vol 11:00 position,phase 180,icbm crossover's set all to 80..............................

pjdami

Looking a lot better Racer. Does it sound better? You should be able to hear a difference in reducing that huge 40 hz peak that you had?

You can definitely work with that curve if you like what you are hearing.

Paul

Dr. Spec

What are you calibrating with that is indicating the sub is 10 dB hotter than the other speakers?

That peak you are seeing in the 70-100 Hz region is due to the fact that the natural roll-off of the speakers in that region is not 4th order.

If you had THX certified speaks with an F3 of 80 Hz and a 2nd order natural roll-off, you would not be seeing that peak. I have the same problem.

Try enabling your low pass filter at 80 hz and see what it does to that peak.

Doc

racer4551

Does it sound better?

pjdami,it sounds ok,used to the bass peaks,sound more mellow now,good though.

set the low pass filter to 80.

Dr.Spec,you mean the filter on the sub?

Dr. Spec

Originally posted by racer4551
Dr.Spec,you mean the filter on the sub?

Yes.....enabling the SVS low pass filter at "around" 80 hz should knock out some of that peak in the 80-100 Hz region. Give it a try.

racer4551

Thanks for the info dr.spec, will give that a run and see.

What are you using for test tones

i used my test tones in my rotel for the sound levels,have found them real close to avia,but like them better because i can get tones for the center back two speakers.

Dr. Spec

Hard to believe the sub is 10 dB louder. The sub level in the 35-70 Hz region is lower than the 80-100 dB region.

It would be nice to see the curve up to 200 Hz to get a better flavor for what is happening with the average speaker level from 80-200 Hz.

racer4551

Originally posted by Dr. Spec
Hard to believe the sub is 10 dB louder. The sub level in the 35-70 Hz region is lower than the 80-100 dB region

Yeah i am kinda confused by this also,but with the speaker levels at 75db the sub reads 86 db? Sorry for the quote notations,still trying to figure out how you post quotes?

gatemplin

Racer,

If you want to see what is going on above
100 Hz, burn these test tones.

http://www.snapbug.ws/sinewaves/

It isnt necessary to burn all of them, but it would give you a broader picture.

racer4551

Will those tones work with the spreadsheet i have now?

gatemplin

No, not that sheet. These tones work with the Excel sheet that you can download at Sonnie's BFD page, the link is at the bottom

http://www.snapbug.ws/bfd

I havent used it but many others have.

racer4551

Ok,here's the latest test sheet ,i used the snapbug tones and their excel sheet.I decided to move the sub back to the left front corner because i really like it there better,it looks better.I KNOW THATS CRAZY!!!but i would really like to make it work if it is possible in this corner.So what are my options to make this curve look a little better?Right now i have eliminated the icbm from the setup and have the rotel set to all speakers small and sub x-over set to 80,svs set to 11:00 gain position and sub x-over to 90.This was the setup for the supplied graph.I would like to try to rid the curve of those two big dips.The dark blue line is the present curve.

gatemplin

That is ugly, the only option with big nulls are tweaking (phase, crossover again) and location. An PEQ is amazing for peaks but you will run out of power trying to fill in nulls like that. I dont know how to fix that without moving it.

racer4551

Yeah that is an ugly graph huh? I have been all over the phase and crossover's to try and pick up those dips and anything i do doesnt really amount to much change in spl in those areas.I was wondering if a bfd1124 would help in this situation,sent an email with the latest graph to them to see what they recommend.If i cant pick up these dips i guess i will move the sub back to the rf corner.Whats crazy it doesnt really sound bad at all,lots of deep bass..........

racer4551

What is the best way to set the phase control on the svs?

gatemplin

You will have deep bass but you will notice things in music you know well, are missing. Like drums that dont hit as hard etc. I had a big dip at 70 Hz and was able to minimalize it with location and phase adjustments and then boost it just a couple of dBs with my BFD. I love the 1124, it can help smooth out the response but with only 16 dBs of signal boost it cant bring that graph up at the nulls.

racer4551

Well i finally decided to move the sub back to the rf corner,got rid of alot of those peaks,looks alot better,this chart is with the sub gain set at 11:00 position,90 phase,90 x-over.................Dark blue line is current read,dont know what that pink line is??

racer4551

Second graph is with sub at 180 phase,90 x-over, lost -2 db's at 45 htz,-3.5 at 50,-4 at 56htz,-1 at 63htz,+2 at 71htz,+8 ! at 80htz,+11 !!! at 89htz, +3 at 100htz,+9 !!! at 125htz, everything else stayed the same,was this a better setting?From 40htz down nothing changed.Any suggestions?.................

gatemplin

Much better. The pink line is Sonnie Parker's sub. Keep checking the phase and pick the flattest one.

racer4551

Yes ,thats with the 15's on also,i think that second move just made alot more peaks?

gatemplin

I changed the post when I saw the second graph. Yeah, I think the first one looks better. I could live with that. How does it sound?

racer4551

Yeah with the first graph settings it sounds pretty good,will go through all the phase and x-over settings on the svs and settle for the smoothest and best sounding.I have been learning alot by doing this and incourage everyone who's interested that it's well worth it in the end.I have found just by repositioning a sub you can change dramatically the sound that it outputs and how it blends with the whole setup .Letalone how much the room affects the bass quality and quanity.