UW: I realized that part. It was just his writing I guess. I am going to try reconnecting the speaker wires and then connecting the RCA to the sub-out on the sub and the sub-out on the 1050, if the 1050 has such a connection. lol

I want to see if that makes any difference. If I don't see any measureable difference or hear anything different I will leave the sub with just the RCA and put it back into the LFE connection.

I tried calling BA and they closed early. I will try them again either Thursday or Monday.

Larry

I spoke with tech support at Boston Acoustics, I’ll try to summarize [Larry, see bottom of message]:

Typically a Dolby Digital receiver has an LFE (Low Frequency Effects) output with a fixed low pass filter (LPF), typically at 80 Hz per THX spec.

The Micro90pvII subwoofer in the BA 9000 II has a fixed LPF (fourth order –24dB/octave slope @ 150Hz), and was engineered to “blend” with the satellites. The Micro 90XII has a built-in high pass filter (HPF) around 150Hz, so it will not try to reproduce bass. Hence, there was not a need for a variable crossover, since it was designed to sound as good as possible out of the box.

Now that Dolby Digital receivers have bass management for fine tuning, if you set the bass management to "SMALL", most receivers utilize a 80-90 HPF for the "SMALL" configuration (“LARGE” configuration provides full range audio).

So if you connected your satellites with speaker wire, and your sub with a line level connection, you would have a gap in between the 90-150Hz band. It may sound OK in the room, but it may sound a little thin.

The Micro90pvII sub was engineered to handle both line level and speaker level connections at the same time, without overloading the input stage.

The line level input “From LFE out” is for the discrete sixth bass channel (“.1”) in the 5.1 setup, which is crossed over to the low freq. by the receiver’s bass management. The line level input “From LFE out” bypasses the crossover circuitry in the subwoofer.

The line level input “From SUB Out” is for an older ProLogic receiver that outputs a full range output that needs to be filtered by the sub. This line level input and the speaker level connections are sent to the 150Hz fourth-order LPF.

With respect to receivers utilizing variable crossover, THX specifies the crossover at 80Hz, which typically works the best. If you set the crossover at 150Hz, it may make the sub a bit directional depending on room placement.

[Larry, what's the crossover (XOVER) freq. setting in the 1050? You might want to try reducing the setting down toward 80Hz (mine's set at 150Hz and sounds fine, but room dynamics may be a big part). Maybe that will reduce the bass coming from the LFE a bit on the "heavy bass scenes". See p.22 of the Outlaw manual.

Also, I looked over your room diagram, and it looks like your sub is WAY to the left. You might try moving the sub away from the edge of the wall a bit to reduce the bass output. Hope this helps ]

Cheers, UW.

UW:

Thanks, glad you were able to get throught to BA.

I can't move the sub from the far left corner of the room because of how the room is layed out with furniture and a 6 foot sliding door between the sub and the edge of the entertainment center.

I have the 1050 set for 150Hz and it does sound directional sometimes. I will try 120Hz and see if that makes it better. I have the RCA cable plugged into the Subs LFE Out connection. I never got a chance to experiment, I am heading down now to play for a little while. I'm going to try both the 120Hz setting on the 1050 while plugged into the LFE out and also the Sub Out connection.

Now that my camera batteries are charged I will also take pictures of the room and show how everything is placed throughout the room.

Let me see if I understand something you said. If I use the LFE Out, then the 150Hz x-over is not being used in the Sub and instead is using the xover from the 1050, right? If I were to use the SubOut then the 150Hz xover is being used and it will ignore the xover from the 1050? Is that what you wrote? I am going to have to double check to make certain I am plugged into the correct connection on the Sub. Maybe that is why I had to unplug the speaker wires.

Ok, I need to head downstairs and check all of this stuff now and I will write down exactly what my settings are for everything when I am finished.

Thanks for the help.

Larry

Right, the Sub is relying on the 1050 providing the Low Frequency Effects signal from the Dolby Digital 5.1 bass management. (Presumably since you're bypassing the low pass filter, you could introduce distortion in the sub by sending signals above 150 Hz through the LFE input).



Almost: the SubOut input sends the signal (assumed to be a full range output 20Hz - 20kHz) to the sub's fixed 150Hz low pass filter (fourth order at -24dB/octave). If the input to the SubOut input is already filtered by the 1050 at 150Hz (second order at -12dB/octave), then the output of the low pass filter in the sub has a much sharper cutoff (-36dB/octave relative to the original signal). Result: probably negligible difference in midrange compared to using LFE input, issue of why use the filter if you don't need it.

It gets more interesting when you have the xover of the 1050 lower than the 150Hz of the sub: say you set the 1050 xover at 100Hz, the signal would have a -12dB/octave slope from 100 to 150Hz, then a -36dB/octave slope past 150Hz. Then again, probably little difference compared to using LFE input.

I think your best bet is to test by using onlythe LFE input, then experiment with the 1050 xover settings at 150, 60, and in between (you should hear some "holes" when xover=60). Then repeat the test with the speaker wires connected as well (this should fill in the holes).

My guess is that you'll use an xover setting around 100 with the speaker wires connected. I hope .

Enjoy your lab work, looking forward to the report.


[This message has been edited by urbnwndsfr (edited December 27, 2002).]

I will be posting an update to this either tomorrow or this weekend.

So far the best sound I am hearing is with the RCA plugged into the LFE on the Sub and no speaker wires. Some DVDs sound great with the x-over at 100Hz and others sound great at 120Hz! lol How can I make the final decision?

I was also able to get my front speaker adjusted evenly by angling the right speaker slightly and they are both now reading 75db's at 62 on the 1050.

I now need to reconnect the speaker wire and run my tests all over again. lol I am using about 6 DVD's with various scenes and rerunning the scenes over and over again to compare the different x-over settings. I have actually done this blindfolded and also have gotten my Mom into the act. lol I have the remote in my hand and have been pressing the xover button and not known what setting has been chosen. In this way I have already ruled out 60, 80, 150 and 200 xovers. 150 was way too directional don't even talk about the others. lol

I am having a real hard time deciding on 100 or 120 though. Maybe with more testing one will jump out at me as sounding better...

I can only imagine how much my house would shake with an SVS.

Larry

Larry
On my setup, Tempest sub and ARdiy speakers (speakers can handle down to 38Hz (measured) before roll-off) I found the best crossover setting of 100Hz. At this setting when measuring with the Spl meter and using a frequency tones disc I found the response the flattest down to 20Hz (don't have any frequency tones below 20 on my disc). I definitely don't hear where the subwoofer is; it blends in very well with my 6 speaker setup. I think every system and room acoustics is unique; therefore experimentation is the key in finding the best crossover point. When listening to multichannel SACD the bass appears to come from wherever the bass is placed on the sound stage.
By the way I'm loving my 1050, a great buy!!!!

MCH:

I am using the Avia disk and it goes down below 20Hz if I remember correctly. I don't recall exactly where I can hear the sub stopping, somewhere in the 30Hz range, probably high 30's.

How do you know your sub is Flat down to 20Hz? Do you actually have some equipment to measure this? I only have an SPL, Avia and my ears. . .

Larry

Larry
For various frequency I have a disc that starts at 20 Hz (for 10seconds), the next track is 25 Hz (for 10 seconds) etc. There are a total of 31 frequency tones, from 20Hz to 20,000 Hz on my disc. When I say flat, I don't mean perfectly flat with exactly the same db level at every frequency; there may be a slight fluctuation: the worst being possibly 3db. I consider this quite good.
In the end you have to satisfy your ear. Don't get too caught up with all the technical stuff. Just sit back and enjoy the music!
Going to watch XXX tonight. This DVD should give my sub a good work out!

Larrry

I agree with MCH. "In the end you have to satisfy your ear." I think the SPL is great for setting channel levels with Pink noise and getting the Sub phase correct but not for tuning an entire frequency range. My NHT subs claim to 21Hz but I can't hear that low so it doesn't matter to me. My personal rule of thumb is to get the levels dialed in then pop in your favorite CD and listen at low and high volumes, adjust subs to YOUR liking, enjoy. I can always tell when something is out of whack when after listening to music at fairly high levels for 30 minutes or so it becomes less enjoyable and irritating. Usually I have the sub set to high.

Hint: If the dog vibrates across the floor or the ornaments are falling off the tree set the sub level back just a bit.