[Syrah]

Thanks for this analoguenut!  Sorry to continue dumbing down this thread, but let me make sure I've got it right.  I just download the program, plug my phono stage out into my computer, play the pink noise track, and it will calculate my curve.

Then I can use my Driverack PA to adjust the EQ at the various frequencies (up or down) based on any inacuracies in my phono stage?  Have I got it?

Right now I use the Rives CD to adjust the bass for room effects.  I could save one program for when I play CD, one for vinyl.

[analognut]

Thanks for this analoguenut!  Sorry to continue dumbing down this thread, but let me make sure I've got it right.  I just download the program, plug my phono stage out into my computer, play the pink noise track, and it will calculate my curve.

Then I can use my Driverack PA to adjust the EQ at the various frequencies (up or down) based on any inacuracies in my phono stage?  Have I got it?

Right now I use the Rives CD to adjust the bass for room effects.  I could save one program for when I play CD, one for vinyl.

No problem man. That's why we're all here anyway, to listen, learn, shoot the b/s and have a good time. I'm still a little confused as to what your original intent was. It definitely sounds like you are confused.

Flattening out the RIAA of your TT eq in order to assist the production of CDs made from your LPs by recording a pinknoise track at hi-rez into the computer is one thing. Equalizing loudspeakers in a room using pinknoise is a completely different setup, and it's best to think about one or the other, not both at the same time!

Looking back at your very first post in this thread I can see the confusion was there from the start. You asked about doing RIAA eq and room eq at the same time, but I didn't pick up on it. It is not possible to do both simultaneously. As noted above, the two require completely different setups.

To use pinknoise to eq loudspeakers in a room you need a 31-band (also known as a 1/3 octave) equalizer with a built-in pinknoise generator to broadcast the sound through your stereo. It will have some sort of metering built in so that you can monitor the levels of each band. Many of these devices come with the flat-response mic you will need to pick up the sound of the pinknoise and feed it in to the eq for analysis. If not, you can Google "flat response mic" and find one that's made specifically for this purpose. I can't remember which company, but I do know that at least one makes a mic just for this purpose. Are you with me on that? The idea is to place the mic in your favorite listening spot. It then picks up the sound of the pinknoise that is being blasted from your speakers, and you'll see on the meters what adjustments need to be made to bring the response of the room to flat. Once you leave your favorite listening spot everything changes again, so beware! Some of these devices have digital attenuators, some use regular sliding pots. The ones that are all digital usually have the capability to automatically adjust the 31 bands for you, which is cool! The old Behringer UltraCurve DSP8000 I mentioned that I use is all digital, using two 24bit processors (one for each channel), has all of the afore-mentioned abilities and much, much more. The next generation box from them was the UltraCurve DSP8024. You can download pics, manuals, and specs from Behringer's website for these old boxes if interested.  Either one of these boxes would work extremely well for doing room eq. You can find them on ebay for around $250-$300. The only downside of them that I know of is that many people found the user interface confusing. It does take some getting used to. Also, that they use one of those annoying greenish LCD displays. Behringer's current version of the product is the UltraCurve Pro DEQ2496, is one rackspace instead of two, and has a smaller display. I read some reviews of this incarnation and discovered that many people have problems with it. Honestly, it sounds to me like you'd be better of with an old 8000 or 8024. It seems there are problems with the DEQ2496 running too hot, and also the bypass relays put pops/clicks into the sound, or just don't work at all. Enough about Behringer and room eq. I think you get the idea now.

Which Driverack do you have? Several models, although limited to 28 bands, have auto-eq for PA or room applications.

If you want to fix the RIAA on your LPs you can place a 31-band eq after your phono preamp and then go into the computer, as long as your phono preamp already has RIAA built into it. I mentioned to you in an earlier posting that if you want to use a mic preamp for your phono-stage the 31-band hardware eq won't work because it won't have adequate cut/boost ability to make the RIAA curve. Yes, you can get the DC6/7 software and use its analyzer together with the 31-band eq and a pinknoise track from a test record to correct the RIAA coming from your preamp to a perfectly straight line. Then, if you don't change any TT settings like VTA, loading, tracking force or damping, you can pull out of the computer and go into your amplifier to play RIAA enhanced music directly from your TT through your loudspeakers in realtime.

I believe you can see now why you'd need two 31-band eq's to do room eq and RIAA enhancement simultaneously. You could play RIAA-enhanced vinyl, or room-enhanced CDs, but you could not play a RIAA-enhanced LP into an equalized room at the same time, unless you make CDs of the LPs, and that's a whole 'nother can o' worms.   

[Syrah]

Thanks again.

I do use my Driverack to compensate for room acoustics.   I use the Rives CD to test my room and system response.  It plays frequencies from 20 hz to 20 khz through my CD player and I use the Driverack to compensate for any peaks and valleys.  So no problem there.

But I'm sure that my TT/phonstage puts out different frequency peaks and valleys then my CD player.  So my plan was to just do two programs in the Driverack, one for CD (that gives a flat room response when a CD is played), one for vinyl (that gives a flat room response when vinyl is played).  I can easily switch from one program to the other on the Driverack.  The problem is that there is no equivalent Rives LP which would make this job really easy.

So you're right, my plan is to use the Driverack to compensate for both room and source peaks and valleys simultaneously, and this works just fine on my CD player.

This is what led me to thinking - why not simply do away with the RIAA curve and build that into the vinyl program on the Driverack?  I think that question has been answered in this string, it's difficult and probably would not sound any better than my (pretty good) phonostage in my preamp.  So I've given up on that one.

But if I can use one of these computer programs to determine the peaks and valley coming out of my TT/phonostage, I could then add and subtract from the Driverack program to compensate for them.  For example, if my CD player/room combination gives me a 3 db peak at 40hz when the 40hz signal is played through my CD player I would have my Driverack adjusted to minus 3 db at 40hz to get a neutral room response.  If my TT/phonostage has a 2 db peak at 40hz as compared to my CD player, then I know that my Driverack program for vinyl playback needs to be set at 2 db less at 40 hz when playing vinyl (so now at minus 5 db).

The intention of my initial post was not in respect of ripping my vinyl to HD (that was merely the use of the device Fremer reviewed).  Although I eventually want to do that too once I have time, so I'm welcome to ideas on that too.  But for now, I'd like to figure out a way to determine my TT/phonostage peaks and valleys from neutral.

[analognut]

For example, if my CD player/room combination gives me a 3 db peak at 40hz when the 40hz signal is played through my CD player I would have my Driverack adjusted to minus 3 db at 40hz to get a neutral room response.  If my TT/phonostage has a 2 db peak at 40hz as compared to my CD player, then I know that my Driverack program for vinyl playback needs to be set at 2 db less at 40 hz when playing vinyl (so now at minus 5 db).

Syrah-

Now I see how I can help you.

You are playing the test CD through your system and adjusting the Driverack to get a flat response in the room. You want a test record with tones so you can make a similar eq setting for your TT.

The Stereo Review Model SRT 14-A Stereo Test Record For Home And Laboratory Use (and others? Help here anyone?) has a test that uses that uses 1/3 octave bands of pinknoise centered on 29 bands across the audio spectrum. It compares the tones at 3 different levels against a reference tone. This would let you use the Driverack to set the system to close to flat using the Driverack, and it should make a big improvement in the sound.

Since test records are so scarce these days, here's this:

A friend of mine collects test records. I know he has duplicates, as well. He recently told me of a man who purchased 10,000 LPs from a radio station and the guy told him he had over 100 test records. Apparently, being able to find them was the catch. My friend was going to visit the guy and buy what he could from him. I'll send him an email and ask if he might have something he could sell you that would help.   

[Syrah]

Perfect.  Thanks so much.

[analognut]

Hey Syrah,

Unfortunately my friend says he actually wants to buy duplicate test records and doesn't have any to sell... too bad.

You could search for "test record LP" or something similar, and watch ebay.

I have the Hi-Fi News and Stereo Review test records I mentioned, but I use them both.

[doctorcilantro]

I mean the curve itself is designed with coefficients and is near perfect. If I want to adjust for cart error, that's another, very customized setup. The very accurate 24/96 VST digital RIAA filter isn't really adjustable unless I dig into with a VST analyzer, so I'm starting with having a perfect curve and hoping the $1200 Grado cart has pretty flat response.

DC

[doctorcilantro]

The Hi-Fi news record has some errors on it. I would recommend the new Ultimate Test Record out.

DC

[doctorcilantro]

A VERY qualified software/audio engineer emailed me this, Richard Tollerton:

"The HFNRR frequency sweep is crap. Do not use it.

The reason should be clearly obvious if you open it up in Audacity in a spectrogram view: the sweep speed is nowhere near constant. In fact, it speeds up significantly around 700hz.... which, not coincidentally, is right around where the frequency response drops in your plots.

My (cynical) hypothesis is that Len Gregory mastered this track by manually turning the dial on an oscillator from 20hz to 20khz. He did advertise that this was an all-analog mastering..... bleh.

Good test records for frequency response are fairly hard to find. I have an old STR151 which is of questionable quality but delivers acceptable results. IIRC, there are some test records in production that have sweeps that are at least not known to be crap, but I forget the details on them. You should look at the Vinyl Asylum archives to research this sort of thing."