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Better bass management. Which way works best without breaking the bank?? (1 Viewer)

Chris PC

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Dennis,
So you don't use an external crossover with your subwoofer? And you find that the subwoofer rolls off above 100 hz using the receivers FRONT=SMALL setting?
Thanx :)
 

Dennis B

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Nov 1, 2001
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Chris,

Y-Y-Yes... when looking at the sub's output only in ETF.

I use the sub's xover...

As I mentioned before, there is higher energy content in frequencies above 100 Hz than I would have expected, but from ETF I have associated them to multiples of the resonant frequencies of my room, rather than poor filtering.
 

Dennis B

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Chris,

Now that I've read you comment on the parallel thread I understood where you're coming from. You say the 6200 might not be rolling off the sub's output above 100 Hz, right?

I have to test that, 'cause my sub's xover is also set @ 100 Hz.
 

Chris PC

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Exactly. Thats what I'm talking about. now the one thing is that our rooms are giving us gain. Great for helping with low bass, but not so great with seeing what the raw signals are coming out of our receivers. As I mentioned, I have been using my subwoofer connected to the sub-out of the Marantz and fronts set the SMALL. I have also just recently tried to use my subwoofers xover at 100 hz in the above setup and it seems to sound ok, but I've got to test more in terms of whats actually happening.

What are you using for test tones?? You have the ETF software? What PC, sound card and microphone are you using? Is that setup easy to do? I might try to go that way if I can afford it.
 

Dennis B

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Chris,
I'm using ETF, which generates its pink noise from the soundcard in the computer directly into my receiver. It also comes with a CD full of tones in case your soundcard is not full duplex.
I'm using a Soundblaster PCI-16, maybe Creative's cheapest, if it's still out there. Almost any card will do the job, because the software will compensate for it.
There's a demo version that you can use without dropping a penny, see if you like it ( Link Removed ). There are also many threads here on how to use it.
 

Chris PC

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David,

Cool. So what mic do you use to input the sound back into the sound card? I have a Sound Blaster 128 PCI. Its fine.
 

Saurav

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I don't like the X-30 because the high pass is limited to 50, 80 or 120 hz or something like that

...

The Mirage xover is infinitely adjustable from 50 to 100 hz just like on the subwoofer itself.
I see. An infinitely variable control would imply a potentiometer, which is usually noisier that a set of fixed resistors selected by a switch. How much noisier, I don't know, and that's your judgement call to make anyway, sonic impact vs. flexibility. I would guess that you would be better off with the Mirage, as precise tuning of the crossover should give you greater benefit than removing a potentiometer.
 

Dennis B

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Nov 1, 2001
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Chris,
I'm using the RS SPL analogue meter. It will do the job, but is rather inaccurate at the lower and higher ends of the spectrum.
You can live with that, but still ETF gives you the ability to use a calibration file. For more info on the correct values and a mod to turn the RS into a top-notch unit, look here:
http://www.hometheaterforum.com/htfo...threadid=60329
 

Chris PC

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Saurav,
It is true that finite crossover points are better. I want to try the least expensive method first. I am assuming that the crossover in the LFX-1 is at least as good or better than the infinitely variable xover in my subwoofer. They operate over the exact same range except of course, my sub has only a low pass. The LFX-1 has a low pass of 50-100 hz and a high pass of 50-100 hz. I can't imagine its too bad.
Now, lets say that the LFX-1 is not an ideal xover and the potentiometer is noisy or causes other phase problems. The next option would be either a Mirage LFX-2 or a Marchand XM9-L. The LFX-2 allows for crossover points of 50, 63, 80 hz or 100 hz. Thats pretty decent. 63 is essentially similar to 60 hz for all practical purposes, and 50 hz is another really good option. 40 hz would be ok, but 50hz is more than adequate and probably as low as I'd want to go. As far as 50 or 63 instead of 60 hz, the LFX-2 also allows for adjustment of the Low Pass shape and the High Pass shape of the crossover. Not sure if thats a potentiometer, but at the very least, it must be better than an actual potentiometer crossover adjustment.
So I guess I'm looking for an LFX-1 for starters. If I find an LFX-2 or Marchand XM9-L for a good price, then thats also a possiblity.
So how do I use the Radio Shack SPL meter with the ETF software? Just connect an RCA to the RS SPL meter and connect that to the mic input of my sound card? Do you use a laptop or have your PC in the same room?
:)
My other option is a Mirage LFX-2
 

Dennis B

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Nov 1, 2001
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Chris,

Check out ETF's site. Under 'demo room' and also on the 'help' tab in the downloaded demo version of the software you'll find good info on how to set it up, including diagrams and tests. There are also many threads about ETF here, particularly in the DIY forum. Most are related to the BFD, but they'll help out as well.
 

BruceD

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Apr 12, 1999
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Chris,

As a heads-up for the RS SPL meter and ETF connection, the RCA cable from the RS SPL meter to the PC goes to the LINE-IN (either left or right), NOT the mic-input.

The LINE-OUT (same stereo channel as RS SPL meter input) goes to the amp input for the speaker under test.

The other stereo input-output pair is looped together with a cable on the PC (input-to-output) to act as a reference.

How this works with a sound card that supports full-duplex:

PC Left LINE-IN from RS-SPL meter

PC Left LINE-OUT to amp (example powered sub input)

PC Right LINE-IN to Right LINE-OUT

PC Right LINE-OUT to Right LINE-IN

1) ETF outputs a test signal through the PC Left LINE-OUT

2) Sub reproduces that signal in the room

3) RS SPL meter picks up signal (at listener's seat)

4) PC Left LINE-IN gets signal from RS SPL meter

5) PC uses Right channel as a soundcard correction reference

6) ETF draws graph from input signal
 

Chris PC

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May 12, 2001
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Wow. Very cool. So I need an 1/8" stereo jack split to left and right in two cases. Lots of cables and connectors!

The setup looks pretty good. What have you done with this software setup so far? Has it helped in placement? Crossover? EQ'ing?

Thanks for the heads up. How good is the DEMO software vs the full version? What sort of use can I get out of the DEMO program? The full version is a little bit pricy for me right now. I think I'll maybe try the demo, but I may just take individual readings for now and plot them, corrected as best I can with the correction values.

Does the full version allow you to play individual tones? Thats the only way I can see myself manually recording the frequency response for each subwoofer location.
 

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