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post #61 of 216 Old 10-13-2013, 10:43 PM
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Today I have put my new Open DRC-AN into the signal chain. I measured from each sub physically to within an 1/8 of an inch to the tip of the audyssey mic and ran a one mic run to see each distance setting to see if each time delay is equal. I got 16.2 ft and 16.4ft. Yesterday it was 12.8 before the mini dsp in the signal chain. Anyway a few pieces of info here. Looking for some answers. When I first plugged in my mini dsp and installed the software everything worked great. I could go in and choose any frequency, say 55hz, boost it in 0.5db increments and the differences were audible with enough db's boosted. I was thinking to myself, this is gonna be nice. The mute and gain controls on the mini dsp interface on my Mac screen all worked. So I decided I was going to run Audyssey any then get a measurement with just audyssey run and then one with audyssey and some mini dsp EQ applied to see how well it could counteract what audyssey left. Like boost the null areas. Anyway after I ran audyssey and entered REW to take my measurements all of the sudden my mini dsp controls were all unresponsive. I took a successful just Audyssey measurement and then engaged the dsp but got the same measurement. With that second measurement being identical I then went into the dsp interface screen and everything was unresponsive that just worked 10 minutes prior. I will post in the dsp forums in hope of some help. One weird thing is the two submersives were set low on the gain knobs (like 4 clicks from the bottom) and the bass levels didn't change when I simply installed the mini dsp into the signal chain. When I went to run Audyssey I had to get the gain up closer to '15' on the gain dial to achieve -1.5db on one and -1.0db on the other. I have a few mysteries here. I'm sure in time I can work them out. But any advice is surely appreciated.

Basically it worked and then I had to change a few settings to get my UMM-6 mic to respond with REW. I have sound flower installed that is used to get my mic to respond with REW. But it continues to pass the signal through so why would all of the sudden the mute, and parametric, EQ any gain be unresponsive?

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post #62 of 216 Old 10-15-2013, 09:03 AM - Thread Starter
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Hi jlpowell84 -- there's lots of stuff in your post and I'm not sure I can help. But I have a few comments. First, getting different distance values is not much of a concern. The OpenDRC-AN might have a longer processing time and thus a larger delay due to the IIR block. But as long as you can compensate for the delay (using either your AVR or the OpenDRC), it shouldn't be a problem at all.

As for lack of responsiveness, I'd try MiniDSP's forum or tech support. To me it looks like the plugin is just not communicating with the DSP anymore. That would explain why the DSP still sends signals to the sub but you can't change the settings. Did you try quitting the plugin, unplugging the unit and trying again?

Note that you shouldn't try boosting the nulls. They're basically energy sinks: you can boost them and just sink acoustical energy without raising the dip because they're typically due to something that rattles or vibrate in your room -- wall, furniture, duct, etc. Boosting the null will only pour energy into that resonance without gaining much. The fix is typically mechanical: either moving the sub so that the new position is less coupled with the thing that rattles; or adding padding or damping or fastening. In my case for example, I have an air duct below my living room and there isn't much I can do to prevent it from vibrating at higher levels.

Good luck and keep us posted with your progress...

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post #63 of 216 Old 10-15-2013, 09:49 AM
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Quote:
Originally Posted by neutro View Post

Hi jlpowell84 -- there's lots of stuff in your post and I'm not sure I can help. But I have a few comments. First, getting different distance values is not much of a concern. The OpenDRC-AN might have a longer processing time and thus a larger delay due to the IIR block. But as long as you can compensate for the delay (using either your AVR or the OpenDRC), it shouldn't be a problem at all.

As for lack of responsiveness, I'd try MiniDSP's forum or tech support. To me it looks like the plugin is just not communicating with the DSP anymore. That would explain why the DSP still sends signals to the sub but you can't change the settings. Did you try quitting the plugin, unplugging the unit and trying again?

Note that you shouldn't try boosting the nulls. They're basically energy sinks: you can boost them and just sink acoustical energy without raising the dip because they're typically due to something that rattles or vibrate in your room -- wall, furniture, duct, etc. Boosting the null will only pour energy into that resonance without gaining much. The fix is typically mechanical: either moving the sub so that the new position is less coupled with the thing that rattles; or adding padding or damping or fastening. In my case for example, I have an air duct below my living room and there isn't much I can do to prevent it from vibrating at higher levels.

Good luck and keep us posted with your progress...

Thanks Nuetro! Yea the responsiveness is really weird. Everything worked when I first installed the unit and the software. The boosting was just to see if it worked, not a permanent fix. I got 8 different graphs last night and all sucked with placements of my dual Submersives. So I am going to rotate my room 90 degrees and have everything symmetrical. This will put my seating in the middle of the room to in relation to the back wall.

I did install the adobe program and the open DRC plug in via flash drive as I just moved. Perhaps and update is needed. Internet is being installed today so I will check.

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post #64 of 216 Old 10-15-2013, 01:54 PM
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The middle of the room is a bad location for your listening position for bass frequencies. Too much cancellation.

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post #65 of 216 Old 10-15-2013, 03:30 PM
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Quote:
Originally Posted by RickD1225 View Post

The middle of the room is a bad location for your listening position for bass frequencies. Too much cancellation.

Well that depends on room length upon witch cancellation will occur. I will actually be about 9.5 ft from the wall/8.5 from tv. And then behind me to the back wall will probably be like 13.5 ft.

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post #66 of 216 Old 10-15-2013, 05:57 PM
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A null always occurs at the exact center of each dimension.

"witch cancellation" -- I think Hansel and Gretel have that covered. smile.gif

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
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post #67 of 216 Old 10-16-2013, 12:59 AM
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Quote:
Originally Posted by DonH50 View Post

A null always occurs at the exact center of each dimension.

"witch cancellation" -- I think Hansel and Gretel have that covered. smile.gif

Darn bass witches! So my new MLP should be about 9-10 ft from the fron wall with the entire length of the room about 24ft. I still have to measure. Dining area back there...

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post #68 of 216 Old 10-17-2013, 08:38 PM
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Big time rookie error!!! I figured out I have to synchronize after certain changes are made!

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post #69 of 216 Old 10-18-2013, 05:07 AM - Thread Starter
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Better synchronize first: once synced, any change you make is applied in real time so you hear it live if content is playing.

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post #70 of 216 Old 10-18-2013, 08:10 AM
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Quote:
Originally Posted by neutro View Post

Better synchronize first: once synced, any change you make is applied in real time so you hear it live if content is playing.

Yea, total rookie mistake. But I figured it out and it's working now smile.gif

Can you tell me in general, why is it bad to use boost? How much is ok?

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post #71 of 216 Old 10-18-2013, 08:56 AM - Thread Starter
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There's nothing wrong with boosting in general. The two occasions where boosting can be a waste are:

  1. Boosting below your sub's cutoff (if ported), or very low in the roll-off. At lower volume you may get a few dBs more but at higher listening levels you'll just hit the sub's limits at that particular frequency faster. That being said, this can be used to gain extension when listening at moderate levels above the cut-off, or not to far down the roll-off for sealed subs. Note that on many sealed subs with DSP-equipped amps, an EQ boost is already present to obtain a relatively flat frequency response. Physics dictate that the un-EQed response of a sealed sub involves a 12 dB/octave roll-off below about 40 Hz; flatness of the sub's response below 40 Hz is typically due to DSP EQing for sealed subs.
  2. Boosting a sharp and deep null. The null is likely caused by something in the room (walls, furniture, ducts, etc.) which absorbs acoustic energy, most probably by rattling or vibrating. Boosting the null will just feed the resonance and cause more rattling / vibration. Typically REW and other automated EQing tools such as Audyssey or the Antimode products will identify nulls and not try boosting them.

Many people also like adding a boost at low frequencies (a house curve). Audyssey DynamicEQ does it in spades when listening at moderate levels. DJ's use very large boosts (e.g. +8-10 dB) around 80 Hz (but with large widths) to provide plenty of chest thump. You might want to try such EQings, but while it's great to show off your sub's capabilities, it's really out of whack when listening to, say, a movie, as in general you don't want to get chest thump when a door is closed on the screen.

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post #72 of 216 Old 10-18-2013, 09:20 AM
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Quote:
Originally Posted by neutro View Post

There's nothing wrong with boosting in general. The two occasions where boosting can be a waste are:

  1. Boosting below your sub's cutoff (if ported), or very low in the roll-off. At lower volume you may get a few dBs more but at higher listening levels you'll just hit the sub's limits at that particular frequency faster. That being said, this can be used to gain extension when listening at moderate levels above the cut-off, or not to far down the roll-off for sealed subs. Note that on many sealed subs with DSP-equipped amps, an EQ boost is already present to obtain a relatively flat frequency response. Physics dictate that the un-EQed response of a sealed sub involves a 12 dB/octave roll-off below about 40 Hz; flatness of the sub's response below 40 Hz is typically due to DSP EQing for sealed subs.
  2. Boosting a sharp and deep null. The null is likely caused by something in the room (walls, furniture, ducts, etc.) which absorbs acoustic energy, most probably by rattling or vibrating. Boosting the null will just feed the resonance and cause more rattling / vibration. Typically REW and other automated EQing tools such as Audyssey or the Antimode products will identify nulls and not try boosting them.

Many people also like adding a boost at low frequencies (a house curve). Audyssey DynamicEQ does it in spades when listening at moderate levels. DJ's use very large boosts (e.g. +8-10 dB) around 80 Hz (but with large widths) to provide plenty of chest thump. You might want to try such EQings, but while it's great to show off your sub's capabilities, it's really out of whack when listening to, say, a movie, as in general you don't want to get chest thump when a door is closed on the screen.

Great info! Ok, you have helped me understand a bit. I do have wood paneling walls that vibrate a little. Audyssey actually levels out a 56hz 8-10db dip I have very nicely. Anyway...

So if I have some nulls then I should not try and boost them. I understand we want flattest response naturally first. But after we find final position can we treat medium to minor dips with the mini?

Let's use what I did last night as a teaching moment. I took three graphs. Pre dsp raw, post dsp&pre audyssey, and then post dsp&audyssey. I tried to present Audyssey with less work. I did get a better looking graph but perhaps it's not good as the REW thread regulars have left my post untouched with zero comments. I don't know, I'm just trying to learn ya know smile.gif
Here are the graphs





And here is post Audyssey without the dsp


I did pull down 20hz too. Is pulling down bad?

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post #73 of 216 Old 10-18-2013, 09:31 AM
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I was advised to not boost anything but to just cut down to match. Yea?

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post #74 of 216 Old 10-20-2013, 06:12 PM - Thread Starter
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Sorry for the delay, I had trouble with my internet connection in the past few days rolleyes.gif
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Originally Posted by jlpowell84 View Post

I do have wood paneling walls that vibrate a little. Audyssey actually levels out a 56hz 8-10db dip I have very nicely. Anyway...

Well I'm not saying the wood paneling is necessarily what causes the dip, but sharp nulls are resonant absorbers generally, or cancellation due to phase mismatch in two sources playing the same signal. The dip you had at 56 Hz is relatively wide, so it's hard to see if it's indeed a dip/null, or if instead you have a peak at 45 Hz and one or two others at 70-80 Hz. Peaks at 45 Hz are extremely common in most rooms and correspond to a room mode for a linear dimension of roughly 12 ft. So you may have better luck trying to level those peaks down to the 55 Hz level than boosting 55 Hz to the level of peaks on either sides... If those are peaks of course, which I'm not sure by the way tongue.gif
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But after we find final position can we treat medium to minor dips with the mini?

I'd say there's no harm in trying! But, if the attempt does not work well, better delete the useless filters; they will pump acoustical energy into the dip for nothing and can impact the other filters.
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Let's use what I did last night as a teaching moment. I took three graphs. Pre dsp raw, post dsp&pre audyssey, and then post dsp&audyssey. I tried to present Audyssey with less work. I did get a better looking graph but perhaps it's not good as the REW thread regulars have left my post untouched with zero comments. I don't know, I'm just trying to learn ya know smile.gif

Well I think you're certainly doing well -- that third graph is pretty nice overall. Minor peaks and valleys but roughly flat to... OMG eek.gifbiggrin.gif

By the way, I was advised to run Audyssey first and tweak its results with EQing afterwards. In any way, if you want to try a non-flat EQ, you *have* to apply boosts post-Audyssey since Audyssey will always try to EQ flat. But it's certainly hard to argue about your results.

Also keep in mind that if you did a full 8-position Audissey MultEQ XT32, it tries to optimize bass across all 8 positions. We seldom have the time and willpower to take REW measurements across 8 listening positions and average those. So while you may want to optimize flatness for a single listening position, keep in mind that Audyssey's results are better than it seems at first sight because of the multi-position optimization.

You might also want to sit back and enjoy your work now for a bit before spending a few more hours on EQing. With that FR, your setup should sound really awesome wink.gif

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post #75 of 216 Old 10-29-2013, 04:03 PM
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When running dual subs and using the minidsp as a splitter (i.e. single sub out from receiver to input 1 of minidsp, then output 1 & 3 to dual subs), what is the proper setting for sub output mode on the minidsp's system settings screen (2.1 advanced plug-in)?

Should it be set to mono mode or stereo mode?

I notice higher db levels on stereo mode (had to cut trim back), but wondering if that is the right setting.
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Quote:
Originally Posted by jlpowell84 View Post

Great info! Ok, you have helped me understand a bit. I do have wood paneling walls that vibrate a little. Audyssey actually levels out a 56hz 8-10db dip I have very nicely. Anyway...

So if I have some nulls then I should not try and boost them. I understand we want flattest response naturally first. But after we find final position can we treat medium to minor dips with the mini?

Let's use what I did last night as a teaching moment. I took three graphs. Pre dsp raw, post dsp&pre audyssey, and then post dsp&audyssey. I tried to present Audyssey with less work. I did get a better looking graph but perhaps it's not good as the REW thread regulars have left my post untouched with zero comments. I don't know, I'm just trying to learn ya know smile.gifWarning: Spoiler! (Click to show)
Here are the graphs





And here is post Audyssey without the dsp


I did pull down 20hz too. Is pulling down bad?
if you have the ability to measure with REW, it's better to let REW calculate the correction and upload it to minidsp.
it worked wonders for me.




beats having to manually change the EQs. REW auto calculation is pretty much spot on in my experience.

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post #77 of 216 Old 10-29-2013, 10:43 PM
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Quote:
Originally Posted by KEVIN C. View Post

When running dual subs and using the minidsp as a splitter (i.e. single sub out from receiver to input 1 of minidsp, then output 1 & 3 to dual subs), what is the proper setting for sub output mode on the minidsp's system settings screen (2.1 advanced plug-in)?

Should it be set to mono mode or stereo mode?

I notice higher db levels on stereo mode (had to cut trim back), but wondering if that is the right setting.
mono mode will mirror the 1st input to the 2nd (left to right) IINM so you don't have to plug in the other input channel.
stereo mode will mix both the left and right (1st input and 2nd), causing +3db increase if it's the same input (split by a Y cable to left and right).
that would explain why you're seeing higher db levels on stereo.

both is fine. there's no (arguably) downside to either.

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post #78 of 216 Old 10-30-2013, 01:47 AM
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Quote:
Originally Posted by paskal9 View Post

if you have the ability to measure with REW, it's better to let REW calculate the correction and upload it to minidsp.
it worked wonders for me.




beats having to manually change the EQs. REW auto calculation is pretty much spot on in my experience.

Really! Didn't know this was available. Can you link or provide a brief description of how to do it ?

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post #79 of 216 Old 10-30-2013, 05:52 AM
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Quote:
Originally Posted by jlpowell84 View Post

Really! Didn't know this was available. Can you link or provide a brief description of how to do it ?
i'm surprised you guys didn't know about this capability. it's even documented at minidsp site.


original article here.

i've been using the function for years. even prior to the article.
a few things i do differently is that i set the target level (inside target settings) to somewhere within the flattest raw response. not necessarily 75db.
i match the range from 20hz to 120hz because i can't stand LFE below 20hz. you might wanna set it to yout sub crossover point (something like 80hz for most people).
if your amp have huge power reserves you could increase the overall max boost to +6db (or reduce it to 0db if you don't want overstressing the amp) and change the max boost to +9db.

usually the result is instantaneous after each EQ modification. it'll show in the next REW sweep.
check the distortion sweep to confirm that the amp & driver is capable to withstand the boost (and max boost).

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post #80 of 216 Old 10-30-2013, 07:20 AM
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Quote:
Originally Posted by paskal9 View Post

i'm surprised you guys didn't know about this capability. it's even documented at minidsp site.


original article here.

i've been using the function for years. even prior to the article.
a few things i do differently is that i set the target level (inside target settings) to somewhere within the flattest raw response. not necessarily 75db.
i match the range from 20hz to 120hz because i can't stand LFE below 20hz. you might wanna set it to yout sub crossover point (something like 80hz for most people).
if your amp have huge power reserves you could increase the overall max boost to +6db (or reduce it to 0db if you don't want overstressing the amp) and change the max boost to +9db.

usually the result is instantaneous after each EQ modification. it'll show in the next REW sweep.
check the distortion sweep to confirm that the amp & driver is capable to withstand the boost (and max boost).

Hey thanks a lot! This really helps out. One more thing, how do you do a distortion sweep?

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post #81 of 216 Old 10-30-2013, 08:53 AM - Thread Starter
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Quote:
Originally Posted by paskal9 View Post

usually the result is instantaneous after each EQ modification. it'll show in the next REW sweep.

I'm not using REW to compute PEQ parameters yet... Are you saying REW is directly communicating with the MiniDSP and updating the filters via USB? If so, in which block does it set the filters? I thought REW simply produced a file with the PEQ parameters, and that the user had to manually load the file into the plugin.

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Quote:
Originally Posted by jlpowell84 View Post

Hey thanks a lot! This really helps out. One more thing, how do you do a distortion sweep?
calibrate the spl (in REW) to an spl meter, and do an increasing sweep. maybe +5db each time. graph (Click to show)
all_qu10.jpg

then check the distortion tab. it's up there next to spl&phase, all spl then distortion. click controls (far right next to limits) and change distortion figures to percent.
and you'll have something like this: distortion graph (Click to show)
quad10.jpg
you can see at what freq the distortion is highest.
if too much boost at a specific freq and the driver or amp can't take it then there'll be very high distortion at that specific freq. try reducing the boost and see if distortion is lower.
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Originally Posted by neutro View Post

I'm not using REW to compute PEQ parameters yet... Are you saying REW is directly communicating with the MiniDSP and updating the filters via USB? If so, in which block does it set the filters? I thought REW simply produced a file with the PEQ parameters, and that the user had to manually load the file into the plugin.
yes rew simply produce a file. you need to upload it manually to the plugin.
if you're running rew and plugging minidsp to the same computer/laptop, then it's just a matter of generating filters from rew, then opening the minidsp window and opening the same file.

you don't need to manually type in the biquads or mess with the knobs. just point minidsp to the rew biquad filters. minidsp will import them.

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post #83 of 216 Old 10-31-2013, 07:41 AM - Thread Starter
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Quote:
Originally Posted by paskal9 View Post

if you're running rew and plugging minidsp to the same computer/laptop, then it's just a matter of generating filters from rew, then opening the minidsp window and opening the same file.

you don't need to manually type in the biquads or mess with the knobs. just point minidsp to the rew biquad filters. minidsp will import them.

Thanks, that's what I thought!

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post #84 of 216 Old 10-31-2013, 03:12 PM
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Any guys in NZ using the Mini DSP with REW and multiple subs?
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post #85 of 216 Old 11-02-2013, 07:17 PM
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Great info in here guys.

I recently plugged a MiniDSP into the chain and configured a 4 sub system using a 2wayadv plugin, 2 SVS SB-12's, and 2 Dayton 18's. I was able to get pretty good response although it was initially challenging getting an even response across 2 couches.

Very recently I moved one of the SVS subs into my office setup, so now I have a 3 sub setup in my living room HT.

Here's the steps I took to configure after setting up the MiniDSP following neutro's guide:

I first used REW's RTA function to find the best locations for the subs. After finding locations where I got best response across both couches, then took 3 seat measurements (2 for the main couch & 1 for the smaller couch) and averaged them together.

In REW I auto EQ'd the averaged response and simply applied those eq settings to each sub. I also applied a low end boost to the 2 Daytons using the first eq block for that extra oomph in the sub 20Hz region.

Initial response with low end boost, no eq and no Audyssey:



After eq, no Audyssey:


 


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post #86 of 216 Old 11-02-2013, 11:51 PM
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^nice work! What did you apply and where?

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post #87 of 216 Old 11-03-2013, 01:08 AM
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I didn't even look at the individual eq settings I imported from REW. But if you're asking about the low end boost then:


 


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post #88 of 216 Old 11-03-2013, 09:12 PM
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Can I get a pic of how you guys are powering the mini dsp? Thx!
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post #89 of 216 Old 11-04-2013, 07:55 AM - Thread Starter
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Quote:
Originally Posted by Spanglo View Post

I didn't even look at the individual eq settings I imported from REW. But if you're asking about the low end boost then:


That's awesome Spanglo, thanks for the details. You've got great results. It looks like REW didn't try EQing below 20 Hz -- did you specifically prevent it from doing so?
Quote:
Originally Posted by Toymachyne View Post

Can I get a pic of how you guys are powering the mini dsp? Thx!

I don't have pics but you have basically two ways of powering the MiniDSP. First is through USB (connected either to a computer with a powered USB port, or to a USB charger e.g. for smartphones and tablets). The second way is to find a wall-wart type power supply (the kind used by small appliances such as wireless phone bases, routers, etc.). Almost any of those will work as the MiniDSP has an internal power regulator. It can accept from 5V to 24V DC I think. The tricky part is that you have to cut the connector and strip the wires. You have to find the polarity of the wires (typically the wire with a white line is +) and screw them in place in the Phoenix connector block. Using the wrong polarity may fry the MiniDSP... But once you're sure of your shot, well you've got an independent power supply for the MiniDSP. If you don't have a power supply in your old stuff box, I guess you can buy one for a few bucks in your nearest electronic store.

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post #90 of 216 Old 11-04-2013, 10:36 AM
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Quote:
Originally Posted by neutro View Post

It looks like REW didn't try EQing below 20 Hz -- did you specifically prevent it from doing so?

I have you to thank neutro. It was your MiniDSP feedback that got me interested, and the simplicity of your guide sealed the deal. Thanks man.

I only played around with boost below 20Hz, and settled on that gain setting because anything higher produced too many rattles and creaks. When I had the gain maxed, every boundary shook violently, and I could hear dishes in the kitchen cabinets and bottles of alcohol on top of my fridge clanking together. eek.gif

Toymachyne - I'm powering with my htpc's usb connection.

 


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