The subject could use a little research, I think numerical simulations using real music signals and synthesized noise with realistic spectral weighting for LP and amplifier could yield some interesting data.
That paper does jump from the time domain to frequency domain when they discuss the spectral weighting of typical LP's. This loses the instantaneous amplitude information.
Here is a practical example:
MM cartridge (5mV typical) ---> analogue gain stage with volume (1V typical) (and optimal input impedance to match the cartridge specs) ---> ADC to USB (eg Focusrite 24/96) ---> digital RIAA via pc ---> USB to DAC in real time.
I know this chain is a nonsense, but what if I just use PC and USB DAC?
I have only to add gain stage and ADC, it's very similar to a DAC and an analogue output stage, only reversed.
A friend of mine has a Focusrite, so I can try.
Do you know if there is out there a JRiver RIAA plugin?
MM cartridge (5mV typical) ---> analogue gain stage with volume (1V typical) (and optimal input impedance to match the cartridge specs) ---> ADC to USB (eg Focusrite 24/96) ---> digital RIAA via pc ---> USB to DAC in real time.
I know this chain is a nonsense, but what if I just use PC and USB DAC?
I have only to add gain stage and ADC, it's very similar to a DAC and an analogue output stage, only reversed.
A friend of mine has a Focusrite, so I can try.
Do you know if there is out there a JRiver RIAA plugin?
What if one wanted to keep this gain stage differential in and out? After all, most ADCs are diff in. The only thing I have to do this is a SSM2018 VCA chip. Any other suggestions?
Yes, but I did find the 1/3 octave graph of LPs before RIAA correction very interesting. Gives one an idea what to expect long term. Next would be to look at peak values for headroom.
I think it is built in. Will have to look. Or you could use the convolution engine. You just need an impulse.
The concept of real time dsp riaa escapes me. Once it's digitized, why not archive it? What would be the point of playing a record again? Ritual?
That's been discussed in other threads. A lot of people have collections big enough that they don't want to bother with the archive. Just pop a record on and have a listen. The DSP becomes just another circuit.
No need to worry about recording, setting levels, naming, trimming, saving, etc. Just play.
No need to worry about recording, setting levels, naming, trimming, saving, etc. Just play.
I have to say, if I could persuade myself that the ADC is transparent (and it is persuade) this could be a nice way forwards.
I guess the only way to know would be a proper, controlled double-blind test - not entirely trivial, as you need an input switcher, and you need to level-match the digital chain to exactly the same gain as the analog chain, and then synchronize the recordings (unless you can set up a low-latency real-time digital chain).
A simple front end pre-amp with cartridge loading options, adjustable gain, and a first order hipass filter, as a normal phono pre-amp first stage, into an A to D sounds interesting.
Digital EQ options would be good for digitising 78 rpm records.
Mono summation, endless variable filters, low pass, hi pass - notch filters etc with a settings database re-callable for each individual record.
Building a analogue pre for 78rpm playback quickly becomes very complicated!
Digital EQ options would be good for digitising 78 rpm records.
Mono summation, endless variable filters, low pass, hi pass - notch filters etc with a settings database re-callable for each individual record.
Building a analogue pre for 78rpm playback quickly becomes very complicated!
There is a VST plugin but I can't connect to jiiteepee's RIAA site. You could probably find it with a search.
Not sure of the input noise on that one for phono, I also see it is last buy status. There are lots of options for single ended to diff which could then be preceded by a low noise in-amp for diff-in/diff-out.
Yes. Like the ones used in pretty much any recording chain, vinyl or CD, since the 90's.
It's probably the easiest way to capture the vinyl effects engine and make unique to each LP.
I don't understand how I can use the convolution engine to everything but the DRC (digital room correction).
Can you explain how I can use it to achieve digital RIAA?
Basically the RIAA curve could just be viewed as a really bad room response, and it is easily corrected with a transfer function calculated from an impulse.
^ What Jukf said.
We just need to find or build an accurate RIAA frequency response curve and make that into an impulse. HOLMImpulse can do it easily. Then plug that into the convolver to correct the signal.
I have used the convolver to do all sorts of EQ and phase adjustments, it ought to be able to do the RIAA curve.
We just need to find or build an accurate RIAA frequency response curve and make that into an impulse. HOLMImpulse can do it easily. Then plug that into the convolver to correct the signal.
I have used the convolver to do all sorts of EQ and phase adjustments, it ought to be able to do the RIAA curve.