|
|
Post by belzarrath on Aug 6, 2010 15:30:45 GMT -7
Hello, Ive started my HT about two years ago and I'm finally getting to The subs.
I have two FI IB 18",
Peavey 8.5c
I'm using REW to measure where to place the sub.
I have the RS SPL.
SB audigy 2zx
I am having trouble with the Measurements step, all previous step worked well.
When I try the measurement step and calibrate I get no right left signals.
The SPL shows a 74db reading but nothing is being picked up in the right channel.
Any help will be much appreciated, I'm anxious to get my Sub in.
|
|
|
|
Post by belzarrath on Aug 6, 2010 18:07:34 GMT -7
Ok, I got that figured, short in the rca jack. Now I have ugly graphs. Maybe i don't need a sub in the ht room  I am going to setup the REW again, make sure all things are correctly done. Attachments:
|
|
|
|
Post by chrisbee on Aug 6, 2010 21:55:24 GMT -7
Hi
Can you explain in a little more detail exactly how you are going about it?
Are both subs/drivers fitted into a manifold?
Is the complete manifold being used as a test sub for measuring?
Do you have the open side of the manifold facing down onto the floor?
Facing the open side down makes a sort of sealed box sub.
This avoids confusion between the fronts and backs of the drivers from upsetting your results.
|
|
|
|
Post by belzarrath on Aug 6, 2010 22:50:53 GMT -7
Chrisbee, thank you for responding,
I am currently using a cheap optimus sub,(two 8" drivers with amp plate) both driver are in phase and in mono mode.
I am trying to place it in different locations next to wall where the manifold will go.
I want to get the best location to place the manifold.
Most of the postions have a simular graph, all fall way below the curve in the beginning.
I hope I'm going about this in the right manner, I'm just worried cuz the graph looks so bad.
|
|
|
|
Post by belzarrath on Aug 9, 2010 13:15:49 GMT -7
Well I'm not for sure what I ve done, but it seems I haven't responded correctly or interestingly enough for individuals to help.
I'm now beginning to build the manifold for the Fis. I can not complete the manifold until I have a spot to place it.
I will try more measurements today. If those measurements aren't improving, I guess I'll just have to place it by blind faith.
|
|
|
|
Post by JeremyG on Aug 9, 2010 17:05:23 GMT -7
I've tried two routes with using REW. One is setting up the mic(SPL meter) at the main listening position, then moving the box sub around and plotting all positions. Then you can pick the best one. The other is to set up the sub at the main listening position, then moving the mic(SPL meter) around the room taking measurements. Personally I find the second easier for me, since I don't have to move the sub nearly as much. Also, using the second method it's easier for me to take measurements close to the ceiling to get a good idea what the room will look like if I use a ceiling mounted manifold. Make sure you measure across the whole wall, and not just in corners. As always, YMMV.
Jeremy
|
|
|
|
Post by chrisbee on Aug 9, 2010 22:27:04 GMT -7
Well I'm not for sure what I ve done, but it seems I haven't responded correctly or interestingly enough for individuals to help. I'm now beginning to build the manifold for the Fis. I can not complete the manifold until I have a spot to place it. I will try more measurements today. If those measurements aren't improving, I guess I'll just have to place it by blind faith. The inference from your last post was that you were going to make more REW sweeps and post your results. We were waiting for these new graphs to appear before advising further. Communication is always a two way deal.  |
|
|
|
Post by lovedoctor on Aug 10, 2010 13:36:44 GMT -7
Something to consider: Don't worry about what the graph looks like, since you aren't going to use this specific sub for actual listening. The goal is to take several measurements at different spots, and then make relative comparisons, e.g. which graph has the fewest peaks/dips. Since the IB sub will have a totally different curve than your test sub, it doesn't matter too much what the overall shape looks like (though others might have another line of thinking on that).
Finally, ThomasW, our illustrious moderator, has a post somewhere here regarding REW. Basically, discuss any troubleshooting problems on a REW specific forum, not on an IB forum.
|
|
|
|
Post by belzarrath on Aug 15, 2010 15:23:49 GMT -7
Well, now thanks for all those responses.
Jeremy, I did try both methods.
Yes the second method is easy however my plots were even looking worse and I wasn't forsure if my mic placement was correct. ( close the the floor)
Sorry, for the miss understanding. I was at a point where I was not forsure if any more measurements would do any good sense they look so bad.
Being as impatient as I am.......
I built the manifold.....
cut the hole into the wall, my best guess for good placement......
and put the sub in two days ago.....
What do I think of it.... well I listened and watched two movies....
I believe I am slightly impressed maybe more.
I will post the few pic I have on the build section and hopefully have a few graph to go with it.
Thanks again.
|
|
|
|
Post by belzarrath on Aug 16, 2010 19:58:56 GMT -7
Heres the new graph, once again. This did not seem to work right serveral time the soundard graph was 15db below the measure woofer. I did not change anything and got these results. It seem I may have to try and go through setup a forth time. Ill start a thred in projects and show what few picture i have. Thanks again,, any suggestions will be appriated. Attachments:
|
|
