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Advice On Eq for TFM122M Wedges

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Russell Ault:

--- Quote from: John Schalk on May 24, 2021, 05:41:15 PM ---One of my goals for this year is to learn how to use some of the audio analysis software that is out there.  I decided to start with Room Eq Wizard.  {...}

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Your timing for this goal is great: there's literally never been a better time to learn about this stuff. Rational Acoustics very generously posted their entire Level 1 training course as a series of YouTube videos (although I'd still recommend the in-person training if and when you get the chance), and the Smaart demo is fully-featured. If you wanted to stay with free software, Open Sound Meter uses many of the same principles as Smaart (and so a good portion of the Smaart training will apply to it, too).

Since your goal is to learn how to use analysis software (and not just EQ some speakers in the relative comfort of your driveway) I'd encourage you to start transitioning from REW to a real-time dual-channel analyzer as soon as possible (they are much more useful in the live audio world).


--- Quote from: John Schalk on May 25, 2021, 09:54:54 AM ---Here is an SPL & Phase plot for the ground plane measurement using REW's Variable Smoothing option which is defined as follows:

Variable smoothing applies 1/48 octave below 100 Hz, 1/3 octave above 10 kHz and varies between 1/48 and 1/3 octave from 100 Hz to 10 kHz, reaching 1/6 octave at 1 kHz. Variable smoothing is recommended for responses that are to be equalised.

With variable smoothing applied, the big dip around 15kHz disappears.  I wasn't planning to apply any Eq above 10kHz anyway.

Note: I just learned how to save an image of the plot area directly in REW and it makes tiny files which is certainly handy for use on this forum!

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Also, I'd really encourage you to keep smoothing to a minimum, especially on the mag trace. Merlijn van Veen gives a great explanation here why, but you've already given yourself an excellent example: smoothing away the null around 15 kHz doesn't actually mean it's not there, it just means that the computer is telling you what is and isn't actionable data, rather than the other way around (and the computer just isn't that smart).

-Russ

John Schalk:

--- Quote from: Russell Ault on May 25, 2021, 10:51:27 AM ---Your timing for this goal is great: there's literally never been a better time to learn about this stuff. Rational Acoustics very generously posted their entire Level 1 training course as a series of YouTube videos (although I'd still recommend the in-person training if and when you get the chance), and the Smaart demo is fully-featured. If you wanted to stay with free software, Open Sound Meter uses many of the same principles as Smaart (and so a good portion of the Smaart training will apply to it, too).

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I was not aware that Rational had posted YouTube videos of their Smaart Operator Fundamentals class.  I noticed that the first couple of videos are 90 minutes long.  I guess that makes sense knowing that they're based on a multi-day, in person training program.  But it does mean that I'll really have to set some time aside to work my way through the class.  The good news is that I've put together a little sound analysis rig so I can set it up in the house and leave things hooked up while I go through their videos.  FWIW I chose REW over Open Sound Meter to get started precisely because there's almost no help available for OSM unlike REW which has tons of documentation, videos, and a very active user forum, even if it is mainly used by home theater enthusiasts.

Russell Ault:

--- Quote from: John Schalk on May 25, 2021, 11:21:59 AM ---I was not aware that Rational had posted YouTube videos of their Smaart Operator Fundamentals class.  I noticed that the first couple of videos are 90 minutes long.  I guess that makes sense knowing that they're based on a multi-day, in person training program.  But it does mean that I'll really have to set some time aside to work my way through the class.  The good news is that I've put together a little sound analysis rig so I can set it up in the house and leave things hooked up while I go through their videos.  FWIW I chose REW over Open Sound Meter to get started precisely because there's almost no help available for OSM unlike REW which has tons of documentation, videos, and a very active user forum, even if it is mainly used by home theater enthusiasts.

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That's fair, and to be clear, there's nothing inherently wrong with REW (the math all works, etc.); it's just that its reliance on sine sweeps means it's not a particularly useful tool in live sound.

The videos are a titch on the long side, but the information they contain is vital. Make sure to grab the Smaart demo before you start watching so you can play along (but also know that at least 80% of the course content is just as applicable to other dual-channel analyzers, so if you ultimately decide to splash out for a SIM rig your time hasn't been wasted). :)

-Russ

Art Welter:

--- Quote from: John Schalk on May 25, 2021, 09:28:32 AM ---I have a spreadsheet that lists Turbo's Eq recommendations for the TFM series, and their PEQ settings line up pretty well to my results too.  They suggest a bump at 300Hz, another at 780Hz, a cut at 1.15Hz, a boost at 2.4kHz, and a final cut at 4kHz. 
I have a Performer 2 which has 4 bands of PEQ on the bus outputs, but it also has a 1/3 octave Eq on every aux bus, so I plan to use those for feedback suppression and voicing.

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John,

Noticed you had applied a 58Hz HPF, the TFM122M box appears to be tuned to around 75Hz, a 70Hz BW24 will keep the cone from flapping  (making vocals gargle..) if you put kick or bass in it.

Almost all the peaks in the TFM122M correspond to it's narrowing pattern at those frequencies, cutting them to "flat" will improve gain before feedback stability, though those frequencies will also become relatively "dead" off axis.
A bump at 780Hz is in a range where the beamwidth is very wide, it makes sense.
Rather than "bumping" 300 Hz, loosing about 5dB from 90 Hz to 200Hz would loose the "mud" typical on stage from mains wrap, and the LF proximity boost from vocal mics, especially if you are running them pre-eq in the monitors.

The missing 16kHz "spike" in your 2M GP measurement is probably due to being off axis, beamwidth narrows to just 30 degrees above 10kHz.

For coax floor wedge voicing, I'd suggest putting the measurement mic as near to a typical (for your use) vocal height above deck (open air, away from any walls or large objects), directly on axis, and shoot for flat response, with a slight rolloff below 200 Hz tapering down to Fb.

Art

Riley Casey:
This goes to the heart of my experience retuning four different monitor rigs over the years, some with factory specs and some 'classic' designs.

- Avoid boosting frequencies in monitor tunings. Added gain makes them slightly more unstable
- High pass should be higher than the same box would be for full range / stick use - 60 to 80 hz
- turn down the high frequency driver - flat to 16k is not beneficial for a wedge monitor in fact anything above 10k is just a problem - in your last curve taking the HF driver down 2db would fix the bump just above crossover and and a shallow cut from 3k to 8k would yield a very stable wedge tuning for loud vocal monitors



--- Quote from: Art Welter on May 26, 2021, 03:09:34 PM ---...
Rather than "bumping" 300 Hz, loosing about 5dB from 90 Hz to 200Hz would loose the "mud" typical on stage from mains wrap, and the LF proximity boost from vocal mics, especially if you are running them pre-eq in the monitors.

...

Art

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