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post #31 of 40 Old 02-12-2014, 09:03 AM
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Quote:
Originally Posted by Spiderm0n View Post

I have been researching this for a few hours this morning and it seems like the deeper I dig the deeper the solution burrows. It looks like I may have to spend hundreds of dollars and on a mic, sound card, etc. Not to mention the time involved in learning REW.

My subwoofer will be in a carpeted basement. It will be an open media room with another room behind it, and I am not looking to achieve perfect sound. How do I pursue the "DB meter and some test tones will get you 90% of the way though." approach? Everything I research seems to lead back to REW.
 

Hence, "rabbit hole."

Frankly, you'll probably be very happy with your system and build.

You'll only become less happy once you start finding out that it can be "better." :D

Don't think of it as a chore, but as another aspect of an interesting hobby. If it doesn't interest you, then, by all means, don't bother.

If you want to bother, REW is an amazing tool, and AustinJerry's guide is a fabulous introduction to it. If you have a laptop with HDMI output, then you just need a USB mic. If you want to get a calibrated one, it will be a little more expensive. Considering your investment in equipment already, another $100 isn't really that big a deal.

You'll probably want a basic RS SPL meter, anyway. Their basic model is fine.

The manual way involves measuring the test tones with the meter and making the necessary changes to get the best response. It's very tedious, which is why everything points you back to REW. But you're welcome to do it the hard way:

http://www.hometheatershack.com/forums/downloads-area/64123-sinewave-test-tones.html#axzz2LbzTLwlK

http://realtraps.com/test-cd.htm

http://realmofexcursion.com/downloads.htm

Hint: use REW.

;)

Michael

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Downloadable FREE demo discs:
http://www.avsforum.com/t/1475769/de...ently-authored 

Did you really need to quote that entire post in your reply?
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post #32 of 40 Old 02-12-2014, 09:23 AM
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Thanks, Michael. I will put subwoofer optimization lower on my list of 100+ things I need to do to finish my basement and build my home theater. Sometimes it gets a bit overwhelming! eek.gif

My theater: Escape from New York theater build

My Gear:
Fusion 12 Tempests (LCR)
Mach 5 UXL 18 - Sealed Subwoofer
Axiom M3v4 & M2v4 Surrounds
Onkyo TX-NR818
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post #33 of 40 Old 02-12-2014, 09:25 AM
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Quote:
Originally Posted by Spiderm0n View Post

I have been researching this for a few hours this morning and it seems like the deeper I dig the deeper the solution burrows. It looks like I may have to spend hundreds of dollars and on a mic, sound card, etc. Not to mention the time involved in learning REW.


I just wanted to address this since a few folks in this thread are on the fence. The miniDSP mic is only $75+shipping and rew is free. That's all you need to start learning and measuring.

Edit: I see Michael beat me to it above but <$100 is a great investment in DIY to get the most out of it.
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post #34 of 40 Old 02-12-2014, 09:32 AM
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USB Mic? I still have the M-Audio MobilePre USB and an XLR Mic. So there is a better, cheaper, faster route now?
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post #35 of 40 Old 02-12-2014, 09:40 AM
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Those will work fine. It's referred to as a "legacy" system, and is what I've been using.

The new route is cheaper, but neither better nor faster.

If the mic has a calibration file, that would be nice. Otherwise, you can:

1. not care

2. have it calibrated

3. buy a calibrated non-USB mic

4. buy a calibrated USB mic and not bother with the MobilePre.


Downloadable FREE demo discs:
http://www.avsforum.com/t/1475769/de...ently-authored 

Did you really need to quote that entire post in your reply?
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post #36 of 40 Old 02-12-2014, 10:28 AM
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http://www.avsforum.com/t/1328136/measurement-mic-shootout-emm-6-wm-61a-rs-33-2055-audyssey

 

If you're just doing subwoofer tuning and you have an audyssey mic and you're not wanting to spend on a new mic now (as mentioned REW is free), read the above and think about your options.  The collected evidence suggests that for subwoofer only tuning you can get good results without spending on another mic.

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post #37 of 40 Old 02-12-2014, 10:54 AM
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Ok, so basically for me it would now be free once I learn REW. I'm in smile.gif

Thanks.

My theater: Escape from New York theater build

My Gear:
Fusion 12 Tempests (LCR)
Mach 5 UXL 18 - Sealed Subwoofer
Axiom M3v4 & M2v4 Surrounds
Onkyo TX-NR818
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post #38 of 40 Old 02-12-2014, 12:50 PM
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With a ported woofer you tend to have more flat extension down lower until you hit the tuning frequency but it takes a bit more time to bud and get it right.. With sealed that roll-off starts much earlier therefore the need to EQ is much greater but it is easier to build. So in short...Peter or Paul...one of them gets robbed. For music it might not matter much because of where most content is. But for HT...having a severe dB loss between 20 and 40 Hz might be very noticeable.

The image below is a SI 18 with 100Watts. One is a sealed (yellow) 5 cubic foot and the other is a ported (grey) 12 cubic foot tuned @ 20Hz. By default you need to EQ the sealed to match the ported to get the same performance not including "room issues". In this example the ported is almost 10dB louder than the sealed @ 20 Hz!. eek.gif This is a classic argument of sealed vs ported; in this case you need almost 10W sealed for every 1W ported @ 20Hz!!!!



The best example I have seen so far of this change is NOTNYT change from sealed to ported with very badass woofers. He still needs to EQ to get things 'flat", but he doesn't need to EQ, power wise, even remotely the same amount anymore to get extension.


Note: I chose 20Hz & 12 cubic because it simplifies the point (flatter extension with ported) I'm trying to make. However, even if I built it I would still measure it to make sure it was doing what I thought it should be doing.

I must be guilty because people say I am guilty because they chose to call me guilty because they refuse to see the truth. Much easier to be part of the mob..
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post #39 of 40 Old 02-12-2014, 01:08 PM - Thread Starter
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Quote:
Originally Posted by pd47 View Post

Which Yamaha receiver do you have?  On mine, and many others I've researched the Yamaha subwoofer out sends all bass signals to the sub (not sure at what point it cuts it, haven't seen the documents on that) and the subwoofer crossover frequency setting within the setup menu's controls how much bass it ALSO sends to your front speakers.  There is no real eq'ing capability for the subwoofer in the consumer Yamaha's I've seen.

I have the RX-V773. There is no EQ that I know of either. There are 3 different eq-like fields you can choose from (Flat/Natural/...) The way I understood it is that by selection whether your speakers are small or large it sends out a certain frequency range and the then sends the lower part of it to your subwoofer. You can also change what range to send to your subwoofer manually from 200hz down to 40hz I think. After that you can also select the level in dbs that you want your speakers at. Including the subwoofer.
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post #40 of 40 Old 02-12-2014, 03:56 PM
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Quote:
Originally Posted by cessna1466u View Post

I have the RX-V773. There is no EQ that I know of either. There are 3 different eq-like fields you can choose from (Flat/Natural/...) The way I understood it is that by selection whether your speakers are small or large it sends out a certain frequency range and the then sends the lower part of it to your subwoofer. You can also change what range to send to your subwoofer manually from 200hz down to 40hz I think. After that you can also select the level in dbs that you want your speakers at. Including the subwoofer.

You would still need a separate EQ devise because all AVR 's, (ie-receivers), lack the ability to boost the bottom end and EQ to suit the room. Also, although I am not fully up to date on the current Yamaha AVR's, but, most of the ones that are newer than 5 years old have a built in room correction system called Ypoe, or something similar, but, be advised that it will not properly EQ a sealed subwoofer either, so either way if you plan to build a sealed sub and use it for theater usage, you will definitely want a separate EQ devise, such as the MiniDsp, or get an amp with built in EQ ability such as the Behringer iNukes. You will also need a mic, and measurement software. I recommend either the UMIK-1 from MiniDsp or the UMM-6 from someone such as Cross Spectrum labs.
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