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MiniDSP - Page 64

post #1891 of 2293
Quote:
Originally Posted by andyc56 View Post

High Q can cause lengthy ringing in the time domain. Paradoxically though, if your system has a narrow peak in its in-room measured response, cutting that narrow peak with a high-Q PEQ may actually reduce the system ringing at that frequency at the position where the mic was placed for the measurement. Whether it actually does depends on whether the system behaves in a minimum-phase manner around that peak. Minimum phase is a complex subject, and if you want to read more, the REW manual has an intriguing section about it.

In any event, the waterfall feature of REW will detect the ringing if present to a significant degree.

Ok I see. I have the evening to take measurements and tinker around so it should be fun. I am going to work on getting my perfected house curve rising about 9 db from 60-80hz down to 30 with a low shelf. Then apply some cuts and maybe a boost. I have one at 56hz that Audyssey completely takes away. Heck without the dsp I am +-3db from 80-20.
post #1892 of 2293
Quote:
Notice also that many of these Q values are way too low to be useful for EQ. They are for demonstration purposes only.
Edited by andyc56 - Today at 1:01 pm

Nicely explained. +1
post #1893 of 2293
So if you have a peak at say....60hz then is that where you would set the "Frequency" part if the PEQ? Then for that peak, (at 60hz) you would want to set the "Gain" at a lower amount? Then conversely, if you have a dip at say...60hz, you would then set the "Frequency" at that 60hz setting and the gain at a higher number?

How do you know what to set the "Q"? What measurement will show you the ideal "Q"?

I am waiting on my measurement equipment to come in, and I plan to get into measuring my subs with REW and EQ'ing them with my 2 by 4 balanced MiniDsp. I need to read up on how to properly measure using REW.

Thank you so much to those of you who are helping us less-skilled folks understand this stuff!
post #1894 of 2293
Quote:
Originally Posted by Martycool007 View Post

So if you have a peak at say....60hz then is that where you would set the "Frequency" part if the PEQ? Then for that peak, (at 60hz) you would want to set the "Gain" at a lower amount? Then conversely, if you have a dip at say...60hz, you would then set the "Frequency" at that 60hz setting and the gain at a higher number?

That's the general idea, yes, If your sub's in-room response has a peak at 60 Hz, you set the center frequency of the filter to 60 Hz, and its "Gain" in dB to a negative number (which gives attenuation of the peak). But you want to avoid boosting a dip, especially a deep one. That's because the boost requires boat loads of power. For example, a 10 dB boost requires 10x the power compared to frequencies at the flat part of the filter.
Quote:
Originally Posted by Martycool007 View Post

How do you know what to set the "Q"? What measurement will show you the ideal "Q"?

REW does all of this for you. Once you get some measurements, there's some dialog boxes you go through. You give REW some information, then it calculates the filter parameters automatically. It's probably best to wait until you have measured data to work with before explaining in detail.
Quote:
Originally Posted by Martycool007 View Post

Thank you so much to those of you who are helping us less-skilled folks understand this stuff!

You're welcome! smile.gif
post #1895 of 2293
Quote:
Originally Posted by andyc56 View Post

That's the general idea, yes, If your sub's in-room response has a peak at 60 Hz, you set the center frequency of the filter to 60 Hz, and its "Gain" in dB to a negative number (which gives attenuation of the peak). But you want to avoid boosting a dip, especially a deep one. That's because the boost requires boat loads of power. For example, a 10 dB boost requires 10x the power compared to frequencies at the flat part of the filter.
REW does all of this for you. Once you get some measurements, there's some dialog boxes you go through. You give REW some information, then it calculates the filter parameters automatically. It's probably best to wait until you have measured data to work with before explaining in detail.
You're welcome! smile.gif

Thanks for clarifying that my friend! It is starting to all make sense now! I forgot about not boosting nulls due to the amplifier head-room issues. I can't wait to get my measurement gear in to start taking some measurements!

Just out of curiosity, would the PEQ settings in a MiniDsp be useful in EQ'ing the LCR's in a small room home theater? Or are the basic PEQ filters, (Frequency, Gain, & Q) only really useful in EQ'ing subwoofers?
post #1896 of 2293
Ok, I have some questions. this is my raw response after finding best placement for my two subs. I applied a 10db low shelf filter at 51hz and Q of 0.9. It seemed to just drop the frequencies above it. Is this right? I am exploring here so this is nowhere near final or anything like that. I am just simply curious is this how the shelf filters work?





I am thinking about making the necessary cuts as you can see on my raw graph, then run Audyssey and then "unbypass" my shelf filter that was bypassed just before I would run Audyssey. I noticed you have to set the low shelf filter first before you do any cuts or it makes the low shelf look really weird. I may apply a boost if needed

It looks to me it really excited that 59 and 105 hz room modes
post #1897 of 2293
also should i turn off my subs when i switch configurations? there seems to be a popping sound that will come one after the other out of my subs.eek.gif
post #1898 of 2293
Quote:
Originally Posted by jlpowell84 View Post

Ok, I have some questions. this is my raw response after finding best placement for my two subs. I applied a 10db low shelf filter at 51hz and Q of 0.9. It seemed to just drop the frequencies above it. Is this right? I am exploring here so this is nowhere near final or anything like that. I am just simply curious is this how the shelf filters work?





I am thinking about making the necessary cuts as you can see on my raw graph, then run Audyssey and then "unbypass" my shelf filter that was bypassed just before I would run Audyssey. I noticed you have to set the low shelf filter first before you do any cuts or it makes the low shelf look really weird. I may apply a boost if needed

It looks to me it really excited that 59 and 105 hz room modes

When you set the "Q" at 0.9, what frequency and what &/or how much gain did you use?
Where you trying to boost a null? If so, keep in mind that boosting a null will seriously begin to eat up you cost you power and headroom.
post #1899 of 2293
So, is it fair to say that one should not apply any kind of boost but instead only apply negative boost to get a flat response?
Would this "rule of thumb" apply more so if one has LOTS of subs?
post #1900 of 2293
Quote:
Originally Posted by Martycool007 View Post

When you set the "Q" at 0.9, what frequency and what &/or how much gain did you use?

Marty, jlpowell is using a shelving filter in this case, rather than a parametric EQ. For a shelving filter, the "Q" has a different interpretation on the graphs than it does for parametric EQ. Let me try to show this with another graph.

This graph is a shelving filter of the type that might be used to boost the low-frequency response of a closed-box sub. I've chosen a low-frequency boost of 10 dB so it's a round number. Response is plotted from 10 Hz to 1000 Hz. To make the graph symmetric, I've chosen the "half-boost frequency" (the frequency where the boost in dB is half of its low-frequency value) to be 100 Hz. I've varied the Q from a minimum value of 0.3 to a maximum value of 1.0 in steps of 0.1. The curve with the most gradual response is the one for Q = 0.3, while the steepest one, which also has some peaking, is for Q = 1.0.


Edited by andyc56 - 10/25/13 at 7:43am
post #1901 of 2293
Quote:
Originally Posted by Martycool007 View Post

Just out of curiosity, would the PEQ settings in a MiniDsp be useful in EQ'ing the LCR's in a small room home theater? Or are the basic PEQ filters, (Frequency, Gain, & Q) only really useful in EQ'ing subwoofers?
PEQ can be used on the main channels as well as for subs – I use it for my front-channel speakers. However, using outboard equalization like the miniDSP on the main channels is an expensive proposition, as it also requires outboard amplification (unless you have the rare AVR that has both pre-outs and amplifier inputs).

Quote:
Originally Posted by jlpowell84 View Post

Ok, I have some questions. this is my raw response after finding best placement for my two subs. I applied a 10db low shelf filter at 51hz and Q of 0.9. It seemed to just drop the frequencies above it. Is this right?
Correct – that’s the way a shelving filter works.

Quote:
Originally Posted by Freniata View Post

So, is it fair to say that one should not apply any kind of boost but instead only apply negative boost to get a flat response?
Would this "rule of thumb" apply more so if one has LOTS of subs?
The “rule of thumb“ only applies to trying to boost nulls; beyond that boosting or cutting is largely academic, as any equalization ultimately enacts a headroom penalty. See here and here for more info.

Regards,
Wayne A. Pflughaupt



post #1902 of 2293
Quote:
Originally Posted by andyc56 View Post

Marty, jlpowell is using a shelving filter in this case, rather than a parametric EQ. For a shelving filter, the "Q" has a different interpretation on the graphs than it does for parametric EQ. Let me try to show this with another graph.

This graph is a shelving filter of the type that might be used to boost the low-frequency response of a closed-box sub. I've chosen a low-frequency boost of 10 dB so it's a round number. Response is plotted from 10 Hz to 1000 Hz. To make the graph symmetric, I've chosen the "half-boost frequency" (the frequency where the boost in dB is half of its low-frequency value) to be 100 Hz. I've varied the Q from a minimum value of 0.3 to a maximum value of 1.0 in steps of 0.1. The curve with the most gradual response is the one for Q = 0.3, while the steepest one, which also has some peaking, is for Q = 1.0.


You completely lost me there. What does this graph represent? What are the various lines on this graph depicting, in laymens terms? I know you said that this shows a low shelf filter with 10db of boost on the low end and the response showing 10hz to 1000hz, I am just completely lost as to what I am looking at in this graph??

So what is the purpose of the half boost frequency and what does it have to do with this graph? What is the graph showing me with this half boost frequency? I know that you said the half boost frequency is 100hz, and that it is half of its low frequency value, but what value are you referring too?
post #1903 of 2293

The graph is showing various Q settings for a shelving filter. Here’s another example that’s perhaps simpler if not as elegant as Andy’s graph. Here’s a shelving filter with a low Q:




...and here’s one with a high Q:




As you can see, the high Q filter basically has a “faster” ramp-up to the point where it plateaus. The 0.9 Q filter you mentioned in Post #1898 is more like the second graph than the first. Make sense?

What are you using for an equalizer? Adjustable Q on a shelving filter is a somewhat rare feature. Adjustment only for the turnover frequency is more typical.

Regards,
Wayne A. Pflughaupt



post #1904 of 2293
Quote:
Originally Posted by Martycool007 View Post


Just out of curiosity, would the PEQ settings in a MiniDsp be useful in EQ'ing the LCR's in a small room home theater? Or are the basic PEQ filters, (Frequency, Gain, & Q) only really useful in EQ'ing subwoofers?

If you do this you should be very careful that you know exactly what your correcting.

Basically no boost above 3db is going to work assuming your correcting room influence on FR.

Below Schroeder Freq your correcting for speaker and LP position to modal distribution.

Above Schroeder your correcting most likely for specular reflections.

Also, you would want to take several measurements across the LP and average them bc EQ is only accurate for one position. Any common anomalies will show in the average and peaks could be shaved along with some minor boost but in my experience boosting any room issues is not worth the headroom loss.
post #1905 of 2293
Thanks for the reply NicksHitachi! Perhaps I will forgo the idea of EQ'ing my mains, (LCR's), and just use my MiniDsp for my subs.

I would, however, like to measure my room and instead of EQ, build some absorbing panels. I have some 2" thick OC703 that I will double up and build a frame that extends 4" from the wa, with 4" of OC703. I will attach these on the side walls, at the first reflection points, and on the ceiling at those first reflection points, then some more on the rear wall.
post #1906 of 2293
There were questions in another thread about the low-end response of the MiniDSP, so here's the response of my balanced 2x4. The subwoofer output on my processor has a LPF that can't be bypassed, so in this sweep it's set to 250hz:



Pretty much dead flat to 3hz, and not even down 1db by 2hz.
post #1907 of 2293
Must be flat to DC. LOL biggrin.gif

That's awesome Luke.
post #1908 of 2293
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.
Edited by KEVIN C. - 10/29/13 at 5:16pm
post #1909 of 2293
Would i be able to use this adapter to connect to my CV-5000? http://www.ebay.ca/itm/HOSA-PHX-206M-Phoenix-Female-PHX3F-to-XLR-Male-Adaptor-6-inch-/151092595878?pt=US_Cables_Snakes_Interconnects&hash=item232dd20ca6&_uhb=1

Is that a male or female Phoenix connection? To me it looks like male but it states in the description that it is female?

Thanks.
post #1910 of 2293
^^^^That should work fine..... a little short on the phoenix to xlr distance, but if your situation warrants it...... looks good.
post #1911 of 2293
Cool. Now do I get male or female Phoenix connector?

Where do I get REW?

Lastly, is there like a step by step guide on how to do everything and configure everything and all that? I am not familiar with any of the software or how or what to adjust.

Thanks.
post #1912 of 2293
post #1913 of 2293
I am building 2 LMS 5400 subs and looking for the best way to EQ them. I've heard a lot about the mini and would like to give it a go. Thing is I'm come really clueless on this EQ'ing thing. I would like to run it in conjunction with REW again I'm clueless.

What would I need to EQ 2 subs? What mini, what plugin, is the USB mic for the mini calibrated? What cables?

Is this something that someone with minimal computer skills be able to accomplish?

Thanks in advance for any help! I'm willing to learn, just don't know where or how to start.

Also I will using a pro amp and I've heard things about input voltages. What should I be looking for regrading this?
Edited by SeekingNirvana - 11/2/13 at 1:21pm
post #1914 of 2293
Quote:
Originally Posted by SeekingNirvana View Post

I am building 2 LMS 5400 subs and looking for the best way to EQ them. I've heard a lot about the mini and would like to give it a go. Thing is I'm come really clueless on this EQ'ing thing. I would like to run it in conjunction with REW again I'm clueless.

What would I need to EQ 2 subs? What mini, what plugin, is the USB mic for the mini calibrated? What cables?

Is this something that someone with minimal computer skills be able to accomplish?

Thanks in advance for any help! I'm willing to learn, just don't know where or how to start.

Also I will using a pro amp and I've heard things about input voltages. What should I be looking for regrading this?

I would recommend the MiniDsp 2 by 4 balanced, and also download REW. Yes, I believe the MiniDsp mic is calibrated.
post #1915 of 2293
So why the 2x4? What is the difference between that and let's say the 8x10....10x10?

I heard you need to buy plugins? Which one?

The pro amp I'm getting will have balanced in, but my AVR (onkyo tx-nr3009) has RCA out. I think you can get cables from RCA to balanced, but what is the advantage of going with balanced? Does it have anything to do with input voltage?
post #1916 of 2293
Quote:
Originally Posted by SeekingNirvana View Post

So why the 2x4? What is the difference between that and let's say the 8x10....10x10?

I heard you need to buy plugins? Which one?

The pro amp I'm getting will have balanced in, but my AVR (onkyo tx-nr3009) has RCA out. I think you can get cables from RCA to balanced, but what is the advantage of going with balanced? Does it have anything to do with input voltage?

There is a cheap software plugin you will buy and then download the install file from the mini dsp site. My open DRC AN was $10 for the plugin
post #1917 of 2293
The 2x4 will allow 4 channels out. What you buy depends on how many channels you need out, how many subs or sets of grouped subs
Edited by jlpowell84 - 11/2/13 at 11:06pm
post #1918 of 2293
Quote:
Originally Posted by jlpowell84 View Post

The 2x4 will allow 4 channels out. What you buy depends on how many channels you need out, how many subs or sets of grouped subs

So what's with the 10x10? 10 subs?! Why did you get the plugin you did, what were the reasons?

I've seen you around Jl and know you have 2 subM's. I'm building 2 LMS's so should I get the same plugin as you?
post #1919 of 2293
Quote:
Originally Posted by SeekingNirvana View Post

So why the 2x4? What is the difference between that and let's say the 8x10....10x10?

I heard you need to buy plugins? Which one?

The pro amp I'm getting will have balanced in, but my AVR (onkyo tx-nr3009) has RCA out. I think you can get cables from RCA to balanced, but what is the advantage of going with balanced? Does it have anything to do with input voltage?

Balanced inputs can help reduce hum in a system, even when used with equipment that has unbalanced outputs. It depends on the cable you use, and generally the right one is wired like this:

post #1920 of 2293
Hi SeekingNirvana,
Quote:
Originally Posted by SeekingNirvana View Post

So why the 2x4? What is the difference between that and let's say the 8x10....10x10?
I would use an 8x10 or 10x10 if I was equalizing a full surround-sound system, where you might actually use 8 inputs. Also, if you are using it as an active-crossover, then you might need six, seven or eight outputs (quantity two 3-way speakers, possibly with subwoofers), although you might only use two of the inputs.
Quote:
I heard you need to buy plugins? Which one?
I can't help you there. Every time I try to read their descriptions of the plug-ins, my head explodes.
Quote:
The pro amp I'm getting will have balanced in, but my AVR (onkyo tx-nr3009) has RCA out. I think you can get cables from RCA to balanced, but what is the advantage of going with balanced? Does it have anything to do with input voltage?
If you have an amplfier with balanced inputs, you will need a miniDSP with balanced outputs. A single-ended miniDSP output would not be able to drive the amplifier's input to full scale.
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