You mean sudden drop after 10kHz? I haven't inserted anything in the audio path.
But, as I said, I did it with notebooks mike which was not really aimed at a speaker.
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Room Measurement Tutorial for Dummies Part 2
- Thread starter amirm
- Start date
You mean sudden drop after 10kHz? I haven't inserted anything in the audio path.
But, as I said, I did it with notebooks mike which was not really aimed at a speaker.
Phase when measuring in-room:
Martin Logan Electrostat with sealed woofer, raw measure (no timing changes or other compensation in REW - just default settigs)
Red, without "room correction", Green, with phase adjustment via DRC, both "unwrapped", no smoothing, both speakers playing, at the listening position, about 10 feet from the speakers.
My cones and domes give the heavily wrapped, or unwrapped "sloping steeply down to the right" display:
Martin Logan Electrostat with sealed woofer, raw measure (no timing changes or other compensation in REW - just default settigs)
Red, without "room correction", Green, with phase adjustment via DRC, both "unwrapped", no smoothing, both speakers playing, at the listening position, about 10 feet from the speakers.
My cones and domes give the heavily wrapped, or unwrapped "sloping steeply down to the right" display:
Hi Amir, I understand how it is when one needs to balance work, family and personal interests. It can be quite challenging but enjoyable all the same. Having said that, any chance of you continuing with the REW tutorial. There are many tutorials online but I really like your teaching style and approach. It's not only informative but fun.
Do you think Dirac Live would work well with miniDSP DDRC-24 as well?
My concern is if that platform is powerfull enough to handle the processing.
https://www.minidsp.com/products/dirac-series/ddrc-24
@RayDunzl, In the specs for openDRC plugin it says max number of taps per channel is 2048, for both 48kHz and 96kHz.
https://www.minidsp.com/products/plugins/minisharc-opendrc-plug-ins/minisharc-4x8-plug-in-detail
Additionaly, in the plugin Data sheet is states this: Up to 9600 @48kHz /3400 @ 96kHz total taps available for the whole platform.
https://www.minidsp.com/images/documents/Product Brief-miniSHARC 4x8 plug-in.pdf
I asked miniDSP support for the exact figures for 2x4HD, will post here when I get the answer.
Btw, their "flagship" product, miniDSP SHD, uses the same SHARC ADSP21489 proc which is in the 2x4HD, except that in the SHD it has been cranked to 450MHz (400 MHz in 2x4HD).
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Biblob
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I am completely new to DSP. Could someone explain to me what the difference would be if I were to use and MiniDSP OpenDRC with, say, AcourateDRC, or I were to use an MiniDSP 2x4 HD with Acourate?
Is the only difference in functionality? If so, where would I need to look at?
Is the only difference in functionality? If so, where would I need to look at?
I am completely new to DSP. Could someone explain to me what the difference would be if I were to use and MiniDSP OpenDRC with, say, AcourateDRC, or I were to use an MiniDSP 2x4 HD with Acourate?
Is the only difference in functionality? If so, where would I need to look at?
You cannot use AcourateDRC with 2x4HD. Take your time and study miniDSP web site, after few days of reading things will hopefully become clear(er)..
I posted numbers for the hardware and plugins I'm using:
When I use rePhase with the OpenDRC-DI and the 2x2 Plugin, I set 6144 taps, at 48kHz and it works. See page 2: https://www.minidsp.com/images/documents/Product Brief-OpenDRC-DI.pdf
When AcourateDRC builds a filter for the OpenDRC-DI, it uses 6144 taps (https://www.minidsp.com/images/documents/Product Brief- OpenDRC 2x2 plug-in.pdf - says 6148, might be a misprint, or maybe a newer version(?)
An empty filter in the "OpenDRC 2x2" plugin:
b0 = 1,
b1 = 0.0,
b2 = 0.0,
...
b6141 = 0.0,
b6142 = 0.0,
b6143 = 0.0
With a filter assigned by AcourateDRC:
When the Dirac firmware is loaded into the OpenDRC-DI, the device operates at 96kHz, and I don't know anything more about it, except it locks it into useage with Dirac and costs more.
That's a different plugin, for 8 channel out? Available memory in the Sharc would be allocated differently.
When I run the 2x4HD with the "MiniDSP 2x4HD" plugin, there is a pool of 4096 taps, allocable among the 4 output channels, defaulting to 1024 for each output channel, and it runs (unverified by me) at 96kHz.
I don't know the Dirac details, being disinterested in Dirac after running their demo and looking at the price a couple of years ago.
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Although the Sharc chips in the different devices may be similar, the way it is implemented/programmed is determined by the firmware/other hardware in the device into which it is installed.
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An "FIR tap" is (my definition) a memory slot for a music sample, a memory slot for the FIR Filter Value to be applied to that slot, and whatever other programming/memory is needed to make it work, from the pool of memory in the Sharc.
I suppose there is another pool of taps/memory allocated for the PEQ/IIR/crossover/compressor/or biquad values on various devices, but I'm ignorant of the particulars.
These (and other?) factors determine the number of taps per channel available from the same/similar Sharc chip in different device configurations.
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OP
- Thread Starter
- #131
Thanks Sam. This is a very time consuming project so I can't produce it as fast as I do reviews. So give me a few weeks to get it done.
Well, I'm sure you can set any number you want in the tap field and it will work producing some kind of result, but the question is the SQ it will produce. How I understood those specs, setting more than 2048 taps per channel can have unknown effects. I guess the only right way to handle it is to consult miniDSP support, hopefully they will provide the right guidelines.
Their support confirmed 2x4HD is running at 96kHz but they have yet to confirm if 1024 taps is max allowed per channel. For OpenDRC they clearly stated it is 2048 per channel.
I have both units, OpenDRC-DI (6144 FIR taps per stereo channel) and 2x4HD (4096 total taps, user-allocable to distribute as seen fit among the four output channels), neither have the Dirac firmware, which changes things, here in front of me. I can manually (rePhase - both units) or automagically (AcourateDRC - OpenDRC-DI only) create filters. The filter values can be loaded into and examined in Excel. They are text files.
Sorry to have inconvenienced you.
I mixed up OpenDRC-DI and miniSHARC 4x8, but don't worry, I'm not that easilly inconvenienced.
Are you saying that you are sure that for 2x4HD1 plugin all 4096 taps can be allocated to a single output, so there is no per channel limit? I didn't found that explicitely stated in the manual so I asked their support.
Anyway, for stereo, 2x4HD1 only supports 2048 per stereo channel at 96kHz while OpenDRC-DI supports 3072 per stereo channel at 96kHz (6144 per stereo channel at 48kHz).
How do you do measurements? UMIK-1 and REW?
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For sound, Yes.
@RayDunzl , do you care to share your pre/post measurements and settings of your system with miniDSP and OpenDRC?
I have, in various other threads.
Looking...
But not particularly finding a best example, and it's bedtime...
Looking...
But not particularly finding a best example, and it's bedtime...
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Here's a zipped .mdat for REW, JBL LSR 308 (original version) and MartinLogan reQuest electrostats, using minDSP OpenDRC-DI and AcourateDRC.
https://www.dropbox.com/sh/i3poj7mwoi0ezfp/AAD-jejRX1Edz4gwESwY4qxea?dl=0
Measured at 10 feet (listening position), mic aimed at phantom center.
1~6 JBL Left/Right/Both Speakers without DRC, L/R/Both with DRC
7~12 ML L/R/Both without DRC, raw L/R/Both with DRC
The DRC is "flat", which may not be to everyone's taste, and the files are 15 months old.
https://www.dropbox.com/sh/i3poj7mwoi0ezfp/AAD-jejRX1Edz4gwESwY4qxea?dl=0
Measured at 10 feet (listening position), mic aimed at phantom center.
1~6 JBL Left/Right/Both Speakers without DRC, L/R/Both with DRC
7~12 ML L/R/Both without DRC, raw L/R/Both with DRC
The DRC is "flat", which may not be to everyone's taste, and the files are 15 months old.
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