Software based RIAA EQ - part 2

[jiiteepee]

Quote:

Originally Posted by doctorcilantro /img/forum/go_quote.gif Is this the correct IIEQ for the .fxp you posted on rapidshare? I note the Pro, Normal (pic below), and the often mentioned Small version, but haven't seen the Small one for download. I'm using ddfm_IIEQ-RIAA_Reproduction-6.fxp with this one: http://1.bp.blogspot.com/_nSEQXVMP03...s1600/IIEQ.jpg

The IIEQ preset #6 you mention is only for this version of IIEQ

http://img255.imageshack.us/img255/8338/iieqriaakv5.jpg

and for operating @ 44.1kHz (I have not measured if it works well @ higher samplerates (this depends on IIEQ features/quality)).

If you don't have it (as it's discontinued) then you need to use ddmf:SmallEQ w/ this preset (this is as accurate now as the IIEQ preset).

http://img231.imageshack.us/img231/7881/smalleqiu2.jpg

You get the SmallEQ downloaded by selecting the FREEWARE section on ddmf site (it's last item in the scrollable list there).

EDIT:

Quote:

The standard RIAA curve has only three time constants. I'm not quite sure how much error will accumulate (I'm speaking of generating spurious distortion and noise, etc., not RIAA error) from those 10 EQ filters, which are probably state variable filters; at least 4 separate coefficients per filter = 40 total; that is one heck of a lot of computation; also, a highpass rumble filter is necessary to remove the LF shelf in that response, or you will have problems. And aside from all that, I don't think that anyone would ever contemplate doing it this way in the analog domain, either...

I don't understand why this answer you got ... person who gave this answer maybe doesn't know the software DSP area well (what all we use on our DAWs?).
Here are couple results from measures done w/ VST Plug-in Analyzer software. Harmonic distortion @ 44.1kHz for this ddmf:IIEQ VST implementation is :

http://img366.imageshack.us/img366/8...eqhd441da8.jpg

and phase:

http://img77.imageshack.us/img77/4828/iieqph441hk2.jpg

so, it looks like even the phase aren't whacked.

(RIAA backround)


jiitee

 

[doctorcilantro]

They look similar but the Menus appear different - could be system dependent; I'm using version 1.12. Can you tell me the version you're using so I can look for it.

It's Freeware, and I'd rather not use the Small version; could you post the earlier Normal (assuming it is pre 1.12?) version for us?

I've also contacted DDMF.

thanks
DC

 

[jiiteepee]

Quote:

Originally Posted by doctorcilantro /img/forum/go_quote.gif They look similar but the Menus appear different - could be system dependent; I'm using version 1.12. Can you tell me the version you're using so I can look for it. It's Freeware, and I'd rather not use the Small version; could you post the earlier Normal (assuming it is pre 1.12?) version for us? I've also contacted DDMF. thanks DC

Mine is v. 1.12. The menus are for VST Plugin Analyzer I've loaded the plugin.

If you use the preset #6 (made just for IIEQ 1.12 (freeware) @ 44.1kHz) with the new IIEQ v. 1.21 (freeware) you'll get result (which are totally wrong) showed in picture (link):

http://img240.imageshack.us/img240/1...iieq121bq8.jpg

W/ this preset #6, you'll get same wrong result w/ the other present versions of ddmf EQs (meaning, SmallEQ, IIEQ Pro, LP10 and Morcky IIEQ) --> looks like every version of ddmf EQ may need it's own preset.
I'll add some presets later for other versions (if I can prepare those).

UPDATE: RIAA EQ preset for IIEQ v. 1.21 Works w/ the Morcky IIEQ as well (adjusted @ 44.1kHz).


Quote:

Analog In: Bix TT>MG-1 tonearm (balanced)>Grado Reference (.5mv)>AEA TRP Ribbon-pre (RIAA free)>Lavry AD-10>Emu1212M Toslink>Samplitude 10 (RIAA via IIEQ VST & Butterworth infrasonic filter)

If you would prefer to use a "lighter" ASIO compatible VST hosting software for the IIEQ setup then, I would recommend the Hermann Seib's SAVIHost (w/o keyboard feature) (or VSTHost)

SAVIHost is quite easy to set-up. You just need to
- copy the savihost.exe into same directory with the IIEQ.dll
- rename the savihost.exe to IIEQ.exe
- run the .exe.
set it up:
Devices-->Wave dialog, set
- Input Port: *no wave
- Output port: E-MU ASIO
- Samplerate: by your audio source
- Buffer: (I normally use same/twice the size as for ASIO buffer)

Devices-->ASIO channel selection dialog, set I/O ports by the connections you've made.
Devices-->ASIO Control Panel ... set the latency.

Load the RIAA preset (PlugIn-->Load Program...)

If engine is OFF the start/Run it.

http://img236.imageshack.us/img236/9...ostiieqze7.jpg


If you like to add the rumble/subsonic filter then just prepare the savihost.exe for ACON's EffectChainer and then load IIEQ and the rumble/subsonic filter (whatever VST/DX it is) into EffectChainer. I normally use energyXT VST or Console VST instead of EffectChainer (IIRC, plogue bidule works as well) or one of those as standalone.

jiitee

 

[doctorcilantro]

Okay, I had too many downloads laying around here I got confused. I see that the new Freeware is 1.21, and I have 1.12 running locally.

THANKS!

 

[jiiteepee]

Hi!

<info + links deleted by me, software was updated with a new version>


jiitee

 

[doctorcilantro]

Quote:

"Higher frequencies are amplified before putting them on the record, and corrected during playback. Since noise is for a large part present in the higher frequencies, so this process makes the signal to noise ratio a lot better"

from: riaa backgrounder 1 - Introduction

IIRC, unmodulated groove noise (rumble) is highest in the low frequencies (<40hz), and the noise floor is actually quite low throughout the rest of the spectrum.

What noise is referred to in the quote above?

DC

 

[doctorcilantro]

Thanks for all the updates (and the update preset for the new IIEQ)! Can't wait to do some testing soon.

DC

 

[doctorcilantro]

Quote:

The above is true only for the standard Lip****z method of EQ. If EQ is split across two stages (the way I do it, for example), then the switch is possible. Quite easily in fact (with the right topology). The 3.18 us turnover point is an extension to the RIAA de-emphasis curve, whose purpose is to compensate for the practical considerations that the RIAA neglected when the standard was created. In this case, that the cutting heads at the mastering facilities were unable to pre-emphasize up to infinity, but instead they were only garanteed up to a certain frequency. The Neumann heads used this turnover point, and they have always been very popular. Many LP masters were cut with this heads. The 3.18 us turnover causes a phono stage to stop its rolling-off of the treble at a frequency of roughly 50 kHz, which in turn causes an added sensation of "air" in the reproduction. However, this tool should be used carefully because some MC cartridges generate too much ultrasonic energy (ringing) when excited by the cliks and pops in the record. On a scope display, the ringing looks like decaying high-frequency tones superimposed on the audio signal. Although this tone is beyond hearing, it could potentially cause trouble to the amplifier or speakers. In my opinion, the solution is to have the option available with a switch, and leave the choice to the listener. This provided that the manufacturer actually understands that the 3.18 us is a zero in the transfer function, not a pole as some designs Raul and I have seen!

from: AudiogoN Forums: What Makes a Good RIAA or Line Stage?

dc

 

[w_m0zart]

@jiiteepee
I tried the April 1, '08 - RIAA Reproduction EQ v.1.o for Max/MSP 4.x

Just for a simple test I grabbed my USB 16 bit sound card (TI/Burr Brown based USB with pcm2902 chipset). Installed Asio drivers which I tested separately. But with your RIAA filter initially sound didn't come out of the output. As it was indicated here on this thread somewhere, I had to 'play' a little bit with the subsonic filter. And indeed, this enabled the filter to output sound.

Now since it is basically working, I would like to ask you if it would be possible to add a simple feature to your script, which takes as input a wav-file instead of a 'realtime' audio source.

The reason for this is I use a Fostex FR 2LE which records directly to Compact Flash at 24 bit. Unfortunately it doesn't output S/PDIF.

Of course, alternatively, it would be possible as well to add some virtual sound output and route that, but I guess my suggested change (or just a separate version) would be quite easy to implement. I can't add it, because the filter is protected.

Hoping you would be able to implement that. If there would be already some option in Max/MSP which I don't know yet (I'm new to Max/MSP) I'd like to hear that as well.

 

[jiiteepee]

Hi

Yes, it's possible to add WAV input as you suggest. It was already on my feature list so, I'll look this and also fix those couple issues regarding no sound output.

BTW, if you're using Asio4All, a simple test tells you if the RIAA filter works as it is intend. When you turn the output off (start/stop button) ... do you still hear audio. If you do hear then, the original signal maybe becomes summed with the filtered signal ... which isn't good (too bright sound, filtered signal is maybe a-bit delayed, ...).

Depending on playback software you're using, you could also use the IIEQ VST version. Foobar, MediaMonkey, Winamp, J.River Media JukeBoc/Center, Steinberg/Pinacle MyMP3PRO 5 (old product) (and few more) supports VST plug-ins either natively or through DSP plug-in (see my sig).

jiitee

 

[henrylar]

I have been playing with this for some days now, and besides the problems with getting it up running it now works fine - up to 88200. I can set the driver sr to more, but if I try to set the filter sr to more all I get is a nasty noise. Any ideas?

FYI: All this stuff is new for me, I have many years in hifi, but I have not mixed it with PC stuff, except creating mp3 for "non hifi" purposes. However, I got interested in experimenting with storing music on computer (flac), and bought an E-MU 0404 USB for the sake of the converter. Then I read elsewhere about using an MC pickup with a balanced mic input, and I rebuilt my wires to the sme arm on my gramophone and use now the mic inputs on the e-mu 0404. No other amplifier in between. Using the riaafilter on the max runtime in this setup is amazing. Enough gain, no hum, and actually a reasonable sound, when using asio drivers when playing it directly.

So thank you for a great piece of work!

However, what can I do to use a higher sampling rate?

 

[doctorcilantro]

You can use the VST plugin for up to 96kHz I believe. I've finally get things setup using Samplitude which allows realtime effects recording/monitoring.

I'll have to double-check on cpu usage because my VFD display isn't always accurate, but I could be using up to 50% of a quad-core that is clocked at 3gHz

Sounds incredible though.....more gobs of thanks to jittee!

DC

 

[henrylar]

@drcilantro

I have just downloaded samplitude to give it a try. Being a novice into this, can you tell me what to do to install the vst plugin in this program?

 

[doctorcilantro]

goota run to work so this will be real quick.

dig in Samp. and set your VST folder location. Put all the VST stuff from jittee and the preset into the same folder.

Samp. will know it's there.

I reccommend using the Samp. menu Window>Mixer to setup things. You can add the effects there by choosing VST and looking for IIEQ. Then load the preset from IIEQ window that pops up.

Use ASIO and you'll need the Hybrid engine running in Options, other options (less cpu intensive) may work to allow realtime effects/monitoring. Not sure if you have to have ASIO or Samp. can do this without.

You can create a new project from a template and delete the other tracks. There is a little speaker icon at the bottom of the Mixer tracks that is the monitor button (the M button is mute).

back later,
DC

 

[jiiteepee]

Quote:

Originally Posted by henrylar /img/forum/go_quote.gif I have been playing with this for some days now, and besides the problems with getting it up running it now works fine - up to 88200. I can set the driver sr to more, but if I try to set the filter sr to more all I get is a nasty noise. Any ideas? ... ... However, what can I do to use a higher sampling rate?

I tested this Max/MSP implementation using E-MU 0404 USB and had no issues @ 96kHz. Have you tried by increasing ASIO latency buffer (try 10ms or more (441 or more as samples))? You can call the ASIO control panel through DSP settings ... Audio Driver Setup -button there on DSP Status screen).
Another possible culprit could be the type of USB port you're using ... as USB 2.0 is needed for higher 'resolution'.


jiitee