BFD Installation and Setup Help

[L.J.]

Well...........................

[Rich-n-Texas]

Well, you know how lazy I am. I have to make sure I've heard a variety of sources and formats before I take the next step, so I can be SURE it's making a difference, right?

[Rich-n-Texas]

Edit: I went ahead and increased the BW to 15Hz.

Here's my first attempt to level the response out. At this time I've only set 1 filter just to see if I'm following the steps correctly and if what I think should happen actually does. This graph is what I expected to see.

BFD parameters:

• Freq = 20Hz
• Setting + Fine = 20 + 0
• BW = 15Hz
• Gain = -10dB

[GMichael]

Looks like you got something going on around 45 htz.

[Rich-n-Texas]

You ain't kidding buster!

I had a different graph up there with an explanation relevant to that one, but I went ahead and replaced it with one where I set the filter to have a wider bandwidth. I didn't do a very good job of editing the text after I replaced the graph, so the post probably didn't make much sense.

Anyway, as kex suggested, I'm trying to flatten out the response starting from the lower frequencies and then working my way up. If I can get everything up to 40Hz toned down closer to the 62 dB level where my lowest frequency measurement starts, then that huge dip won't look so dramatic. I'll worry about the "House Curve" setup later on.

[audio amateur]

Damn, I need to get myself a nice HT system and tweak away too!!! This is the kind of stuff I'd love to do..
Good luck with it Rich, you're getting all the advice you could possibly need!

[Rich-n-Texas]

I have to tell ya the truth. I'm starting to lean towards the REW method. The only other piece of hardware I need is the USB "soundcard" which has Line-out L/R & Line-in L/R. I can get exactly what the crew at HTS talks about direct from Behringer for under $50, and since I already have a laptop and necessary cabling, there'd be no other expense. The materials I need to finish my panels have already been paid for as well.

I get it that the manual mode, while tedious is probably going to give me better results, as has been pointed out, but OTOH the REW would quicken the process and satisfy the computer geek in me. We'll see, but in the meantime I'm plodding along in manual mode.

[kexodusc]

I have to tell ya the truth. I'm starting to lean towards the REW method. The only other piece of hardware I need is the USB "soundcard" which has Line-out L/R & Line-in L/R. I can get exactly what the crew at HTS talks about direct from Behringer for under $50, and since I already have a laptop and necessary cabling, there'd be no other expense. The materials I need to finish my panels have already been paid for as well.

I get it that the manual mode, while tedious is probably going to give me better results, as has been pointed out, but OTOH the REW would quicken the process and satisfy the computer geek in me. We'll see, but in the meantime I'm plodding along in manual mode.

Hey rich - get crackin'.

I wouldn't bother with the frequencies below 20 Hz much. Go after the audible stuff in 20's and higher first. Try some cuts, tell us what you did and post your results. Shouldn't take too long. I made a cheat sheet on a note pad to get the steps in the right order - made it quicker for me.

[bfalls]

I didn't see it listed in the thread, but there's a correction list for the Radio Shack SPL meter Rich is using with substantial correction for the low frequencies. I found this one on the Audiogon Forum site. It's listed all over the web.

10Hz +20.5
12.5Hz +16.5
16Hz +11.5
20Hz +7.5
25Hz +5
31.5Hz +3
40Hz +2.5
50Hz +1.5
63Hz +1.5
80Hz +1.5
100Hz +2
125Hz +0.5
160Hz -0.5
200Hz -0.5
250Hz +0.5
315Hz -0.5
400Hz 0
500Hz -0.5
630Hz 0
800Hz 0
1KHz 0
1.25Khz 0
1.6KHz -0.5
2Khz -1.5
2.5Khz -1.5
3.15Khz -1.5
4KHz -2
5KHz -2
6.3KHz -2
8KHz -2
10Khz -1
12.5KHz +0.5
16KHz 0
20KHz +1

[Luvin Da Blues]

I'm starting to lean towards the REW method. The only other piece of hardware I need is the USB "soundcard" which has Line-out L/R & Line-in L/R.

Rich, I have a USB SC I'm not using anymore if your interested. Let me know.

[GMichael]

What a place we have here!

[Rich-n-Texas]

Rich, I have a USB SC I'm not using anymore if your interested. Let me know.

Thanks LDB. It has to have Line-in & Line-out as opposed to Mic & headphone. I'd suggest that shipping it would cost more than just buying one since it would be an overseas shipment correct?

bfalls, the Excel table that I plug the readings from the RS meter into automatically convert the raw SPL numbers to "compensated" numbers (based on the model # of the meter) using a formula in each cell. Thanks for posting that in any event.

[Luvin Da Blues]

Thanks LDB. It has to have Line-in & Line-out as opposed to Mic & headphone. I'd suggest that shipping it would cost more than just buying one since it would be an overseas shipment correct?.

Well Rich, it does have line in and 5.1 line outs, unfortunately they're 1/8" mini jacks. Yer probs right bout the shippin' tho.

[audio amateur]

I'll be in the US in a month and was hoping to buy an SPL meter while I'm at it. Can I simply go to any Radio Shack store and buy one? If so, how much is it and would a be a good choice?

[Rich-n-Texas]

The model number of the Radio Shack SPL meter I got is 33-4050. This is the analog readout style, and you can use the correction table from the Home Theater Shack site to compensate for this el-cheapo meter when you're taking the measurements.

I ordered mine online, FYI.

[Rich-n-Texas]

Here are the results of my first attempt. I'm including the settings for the five filters because I really don't understand why I got the results I did, so maybe by including them, someone can explain this graph to me.

Filter #1: Freq = 20Hz - Setting + Fine = 20+0 - BW = 55/60 - Gain = -15

Filter #2: Freq = 38,3Hz - Setting + Fine = 40-4 - BW = 30/60 - Gain = -15

Filter #3: Freq = 50Hz - Setting + Fine = 50+0 - BW = 20/60 - Gain = -8

Filter #4: Freq = 80Hz - Setting + Fine = 80+0 - BW = 20/60 - Gain = -15

Filter #5: Freq = 110Hz - Setting + Fine = 100+8 - BW = 10/60 - Gain = -5

It's still not quite clicking in my head how the bandwidth settings are made and how they effect the response curve, even though kex has explained it to me every which way but Sunday.



Your help in this matter is highly anticipated and appreciated.

[Rich-n-Texas]

I watched a movie last night with a DTS-HD sound track, and as expected (I assume), the sub output was down. I experimented by switching the BFD into bypass, and while the lows picked up a bit, it still didn't seem to have the same impact as previously when I used Dark Night as a reference, so I'm blaming it on the rental (Saw IV). I still have to readjust the volume on the sub's amp to get it level-matched with the other speakers, so last night's tryout was just preliminary.

[GMichael]

It looks like a good start to me Rich. It was expected that your overall output would be down. You had to lower the output of all the frequencies around your dip at 45 to get a flatter response. You can turn up the master volume on your sub to bring it back up to where you like. Now you should be able to hear more of the 45 htz than before, while the rest are under control.
I would guess that there is still more you could tweek though.

[Rich-n-Texas]

Thanks GM and I agree. That 45 Hz dip, while not as dramatic anymore could use some boost. When I tried to boost that range previously, the actual gain seemed to occur at about 54Hz and took that 56Hz peak through the stratosphere so I quickly removed it.

I was calibrating with the sub's volume at about 1/3 so yeah, I have plenty of wiggle room.

[GMichael]

Thanks GM and I agree. That 45 Hz dip, while not as dramatic anymore could use some boost. When I tried to boost that range previously, the actual gain seemed to occur at about 54Hz and took that 56Hz peak through the stratosphere so I quickly removed it.

I was calibrating with the sub's volume at about 1/3 so yeah, I have plenty of wiggle room.

You could have some room canceling going on. (That whole node, mode or whatever thingy) If so, then I think that all your boosting at 45 will do no good other than to boost everything around it. Did you put those panels up yet?

[Rich-n-Texas]

You could have some room canceling going on. (That whole node, mode or whatever thingy) If so, then I think that all your boosting at 45 will do no good other than to boost everything around it. Did you put those panels up yet?

Umm... well, I, uhhhh...

I've got four more panels to assemble, and two of those pre-made designer frabric panels to hang, so while I'm hanging a new ceiling fan this weekend...

So would you say I'm at a good stopping point for now, and that I should continue to treat the room? I realize that the panels won't directly affect the sub frequencies, but dumbing down the reflections at higher frequencies is still a good thing to do. The walls are still essentially bare.

[GMichael]

Umm... well, I, uhhhh...

I've got four more panels to assemble, and two of those pre-made designer frabric panels to hang, so while I'm hanging a new ceiling fan this weekend...

So would you say I'm at a good stopping point for now, and that I should continue to treat the room? I realize that the panels won't directly affect the sub frequencies, but dumbing down the reflections at higher frequencies is still a good thing to do. The walls are still essentially bare.

Stopping? What are the odds of that?

Bare walls are not your friends. Once you put up those panels, you may have different readings. I'd think that you'd be better off setting those up before you finish tweeking the BFD. But that doesn't mean that you couldn't pump up the volume a little first.

[Rich-n-Texas]

Actually I did increase the sub's volume last night after the movie, and I'll take some time tonite to match it up to the rest of the speakers. Then I'll play that sequence from Dark Night again and adjust the sub accordingly. (Edit: Wait a minute, I wonder if changing the sub out volume at the receiver will change the readings )
BTW, I just bought this: http://www.behringer.com/EN/Products/UCA202.aspx ($39) so I can start using the REW s/w.

[GMichael]

HMMmmm... Very interesting. I've saved that link now. Tanx.

I think I remember Kex and/or LJ saying that turning the volume up on the sub is better than changing the receiver's LFE output level. Something about headroom, distortion or such.

[L.J.]

Yeah you adjust the volume from the sub. Once the AVR sub output is set, you leave it alone.

Rich, what's the problem with your response? Looks like your doing a good job. Bump up the volume to match the rest of your speakers. Actually, my sub is probably bumped 3-4 db above the rest of my system.