As you have probably surmised from the title, this will be used for
transferring vinyl LPs to a digital CD-ROM format (16 bits and 44.1
kHz).

Turntable will be a Rega P-3 with a Rega Super Elys cartridge.

Here is my question:
I have a choice between an Echo Mia-MIDI or TerraTec DMX 6FIRE 24/96
sound card to do the AD conversion. With the DMX 6Fire I can run the
turntable directly into the break-out box and skip the Phono Pre amp
altogether and do the RIAA equalization in software. To me this looks
like a real attractive alternative to the more traditional approach of
Turntable Phono PreAmp Sound card. It also saves me $600 to $1,200
in cost which is pretty significant in my world. It also avoids all of
the problems that might be related to my PreAmp coloring the sound as
well (yes I'm thinking tubes).

I want the best quality recordings that I can REASONABLY obtain, but
if the difference will be dramatically better with the Mia-MIDI and a
good Phono PreAmp then I will have to go with that option. If the
results will be the same or so close that I could not tell, then I
will take the cheaper way out. The most important thing to me is to
get it right. I really want to stay away from some of the more extreme
"audiophile" solutions that call for $1,000 interconnects. I just
don't have the cash to chase after the last .05%. :-)

I plan to sample at 24 Bit/88.2 kHz and then do my final down sampling
after I'm done cleaning up and de-clicking, if that information will
be of any help.

This setup will basically be a "one trick pony". All this sound card
will do is record LPs and I have have no other audio components that I
wish to interconnect so the Phone Preamp will never be used to listen
to vinyl unless I'm doing a transfer.

So which way is better?

Thanks for getting this far! :-)

Jimmy The Clam wrote:
As you have probably surmised from the title, this will be used for
transferring vinyl LPs to a digital CD-ROM format (16 bits and 44.1
kHz).

Turntable will be a Rega P-3 with a Rega Super Elys cartridge.

Here is my question:
I have a choice between an Echo Mia-MIDI or TerraTec DMX 6FIRE 24/96
sound card to do the AD conversion. With the DMX 6Fire I can run the
turntable directly into the break-out box and skip the Phono Pre amp
altogether and do the RIAA equalization in software. To me this looks
like a real attractive alternative to the more traditional approach of
Turntable Phono PreAmp Sound card. It also saves me $600 to $1,200
in cost which is pretty significant in my world. It also avoids all of
the problems that might be related to my PreAmp coloring the sound as
well (yes I'm thinking tubes).

I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent tests
that show how this unusual feature actually works.

"Arny Krueger" wrote in message
...
I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent
tests
that show how this unusual feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

I know the card has a greater dynamic range than vinyl, but are you saying
that what would come off the record would be reduced further or just that
the full range that the card has to offer would be reduced?

Thanks for the reply Arny!

Jimmy The Clam wrote:
"Arny Krueger" wrote in message
...

I've got some concerns about the fact that the DMX's RIAA
equalization is done with software. Historically, this has involved
some compromises in terms of dynamic range. I can't find any
detailed specs or independent tests that show how this unusual
feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency response
followed by the equalization implemented in the digital domain, You need to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1 volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2 volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts, which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation, which
is a somewhat better than you can get with a good turntable and a very clean
record. It's not that much worse than conventional high quality RIAA preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to 100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

This looks REALLY intriguing and perhaps the idea of "software" RIAA has
finally arrived; maybe, I hope.
As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.
More details he
http://productsen.terratec.net/modul...rticle&artid=4

The phonograph cartridge I want to use is the Rega Super Elys with an output
of: 6.8mV - 7.2mV

What questions should I ask them to get a better handle on the capabilities
of this card as I intend to use it?
I will post their answers for further discussion and follow up.

Thank you Arny.



Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency
response
followed by the equalization implemented in the digital domain, You need
to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1
volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it
by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2
volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output
of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts,
which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a
lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation,
which
is a somewhat better than you can get with a good turntable and a very
clean
record. It's not that much worse than conventional high quality RIAA
preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to
hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an
interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to
100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

Jimmy The Clam wrote:

This looks REALLY intriguing and perhaps the idea of "software" RIAA
has finally arrived; maybe, I hope.

As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.

If you search on

rightmark DMX 6FIRE

You'll see some independent numbers. I characterize the card as having 95 dB
dynamic range which is very good.

More details he

http://productsen.terratec.net/modul...rticle&artid=4

Not enough detail.

The phonograph cartridge I want to use is the Rega Super Elys with an
output of: 6.8mV - 7.2mV

Somewhat more output than usual, but not out-of-bounds.

What questions should I ask them to get a better handle on the
capabilities of this card as I intend to use it?

At some point you'll probably buy it and pray for a good return policy if it
turns out to not be what you want.

Jimmy The Clam wrote:

This looks REALLY intriguing and perhaps the idea of "software" RIAA
has finally arrived; maybe, I hope.

As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.

If you search on

rightmark DMX 6FIRE

You'll see some independent numbers. I characterize the card as having 95 dB
dynamic range which is very good.

More details he

http://productsen.terratec.net/modul...rticle&artid=4

Not enough detail.

The phonograph cartridge I want to use is the Rega Super Elys with an
output of: 6.8mV - 7.2mV

Somewhat more output than usual, but not out-of-bounds.

What questions should I ask them to get a better handle on the
capabilities of this card as I intend to use it?

At some point you'll probably buy it and pray for a good return policy if it
turns out to not be what you want.

Jimmy The Clam wrote:

This looks REALLY intriguing and perhaps the idea of "software" RIAA
has finally arrived; maybe, I hope.

As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.

If you search on

rightmark DMX 6FIRE

You'll see some independent numbers. I characterize the card as having 95 dB
dynamic range which is very good.

More details he

http://productsen.terratec.net/modul...rticle&artid=4

Not enough detail.

The phonograph cartridge I want to use is the Rega Super Elys with an
output of: 6.8mV - 7.2mV

Somewhat more output than usual, but not out-of-bounds.

What questions should I ask them to get a better handle on the
capabilities of this card as I intend to use it?

At some point you'll probably buy it and pray for a good return policy if it
turns out to not be what you want.

Jimmy The Clam wrote:

This looks REALLY intriguing and perhaps the idea of "software" RIAA
has finally arrived; maybe, I hope.

As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.

If you search on

rightmark DMX 6FIRE

You'll see some independent numbers. I characterize the card as having 95 dB
dynamic range which is very good.

More details he

http://productsen.terratec.net/modul...rticle&artid=4

Not enough detail.

The phonograph cartridge I want to use is the Rega Super Elys with an
output of: 6.8mV - 7.2mV

Somewhat more output than usual, but not out-of-bounds.

What questions should I ask them to get a better handle on the
capabilities of this card as I intend to use it?

At some point you'll probably buy it and pray for a good return policy if it
turns out to not be what you want.

This looks REALLY intriguing and perhaps the idea of "software" RIAA has
finally arrived; maybe, I hope.
As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.
More details he
http://productsen.terratec.net/modul...rticle&artid=4

The phonograph cartridge I want to use is the Rega Super Elys with an output
of: 6.8mV - 7.2mV

What questions should I ask them to get a better handle on the capabilities
of this card as I intend to use it?
I will post their answers for further discussion and follow up.

Thank you Arny.



Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency
response
followed by the equalization implemented in the digital domain, You need
to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1
volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it
by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2
volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output
of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts,
which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a
lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation,
which
is a somewhat better than you can get with a good turntable and a very
clean
record. It's not that much worse than conventional high quality RIAA
preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to
hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an
interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to
100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

This looks REALLY intriguing and perhaps the idea of "software" RIAA has
finally arrived; maybe, I hope.
As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.
More details he
http://productsen.terratec.net/modul...rticle&artid=4

The phonograph cartridge I want to use is the Rega Super Elys with an output
of: 6.8mV - 7.2mV

What questions should I ask them to get a better handle on the capabilities
of this card as I intend to use it?
I will post their answers for further discussion and follow up.

Thank you Arny.



Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency
response
followed by the equalization implemented in the digital domain, You need
to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1
volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it
by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2
volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output
of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts,
which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a
lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation,
which
is a somewhat better than you can get with a good turntable and a very
clean
record. It's not that much worse than conventional high quality RIAA
preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to
hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an
interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to
100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

This looks REALLY intriguing and perhaps the idea of "software" RIAA has
finally arrived; maybe, I hope.
As the manufacturer Terratec is stating, that this card has:
24bit/96kHz AD converters with 100 dB dynamical range (S/NR)
24bit/96kHz DA converters with 110 dB dynamical range (S/NR)
So hopefully this card has the juice to pull it off.
More details he
http://productsen.terratec.net/modul...rticle&artid=4

The phonograph cartridge I want to use is the Rega Super Elys with an output
of: 6.8mV - 7.2mV

What questions should I ask them to get a better handle on the capabilities
of this card as I intend to use it?
I will post their answers for further discussion and follow up.

Thank you Arny.



Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency
response
followed by the equalization implemented in the digital domain, You need
to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1
volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it
by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2
volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output
of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts,
which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a
lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation,
which
is a somewhat better than you can get with a good turntable and a very
clean
record. It's not that much worse than conventional high quality RIAA
preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to
hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an
interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to
100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

Jimmy The Clam wrote:
"Arny Krueger" wrote in message
...

I've got some concerns about the fact that the DMX's RIAA
equalization is done with software. Historically, this has involved
some compromises in terms of dynamic range. I can't find any
detailed specs or independent tests that show how this unusual
feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency response
followed by the equalization implemented in the digital domain, You need to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1 volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2 volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts, which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation, which
is a somewhat better than you can get with a good turntable and a very clean
record. It's not that much worse than conventional high quality RIAA preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to 100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

Jimmy The Clam wrote:
"Arny Krueger" wrote in message
...

I've got some concerns about the fact that the DMX's RIAA
equalization is done with software. Historically, this has involved
some compromises in terms of dynamic range. I can't find any
detailed specs or independent tests that show how this unusual
feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency response
followed by the equalization implemented in the digital domain, You need to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1 volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2 volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts, which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation, which
is a somewhat better than you can get with a good turntable and a very clean
record. It's not that much worse than conventional high quality RIAA preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to 100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

Jimmy The Clam wrote:
"Arny Krueger" wrote in message
...

I've got some concerns about the fact that the DMX's RIAA
equalization is done with software. Historically, this has involved
some compromises in terms of dynamic range. I can't find any
detailed specs or independent tests that show how this unusual
feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

At some frequencies in the audio range, probably yes.

There's 40 dB of equalization in the RIAA curve. It's basically a giant
roll-off that levels off for a while in the middle.

A RIAA preamp stage generally has about 36-40 dB gain in the midrange,
about 56-60 dB gain at 20 Hz, and 16-20 dB gain at 20 KHz.

If you implement this as a broadband amplifier with flat frequency response
followed by the equalization implemented in the digital domain, You need to
have 56-60 dB gain at all frequencies. IOW. to have the equivalent of 1 volt
of output at 20 KHz, you need to have close to 100 volts and attenuate it by
40 dB. The usual RIAA preamp designs attenuate the signal before it gets
that big.

Consumer sound cards generally have maximum input in the range of 1-2 volts.
If you attenuate that by 40 dB, you have 10-20 millivolts. So the output of
the flat response preamp at 20 Hz, is now limited to 10-20 millivolts, which
is a very small signal. If the card starts out with 95 dB SNR, then the
equivalent SNR at 20 Hz is 55 dB. The good news is that 20 Hz is a
frequency where the ear is insensitive and the turntable is producing a lot
of noise of its own.

Over the whole audio range, the SNR limit due to the flat response preamp
design might average out to be more like 75 dB in this implementation, which
is a somewhat better than you can get with a good turntable and a very clean
record. It's not that much worse than conventional high quality RIAA preamp
designs.

The plus is that the equalization can be implemented in the digital domain
and therefore be highly precise. Expensive high-tolerance capacitors for
equalization (usually 2 per channel) aren't needed.

I think that with the needle up and gains matched, you might be able to hear
a difference in the sound of the background noise, if you compared a flat
response phono preamp followed by a digital equalizer implemented in the
computer, as compared to a standard RIAA preamp. It would be an interesting
experiment. Needle on the record, it could be a horse race.

People including myself have thought about implementing a preamp this way
for years. The plus is that it eliminates the cost of some expensive
precision capacitors and some modest-priced but not cheap precision
resistors.

I know the card has a greater dynamic range than vinyl, but are you
saying that what would come off the record would be reduced further
or just that the full range that the card has to offer would be
reduced?

I just don't know the actual details of how they do what they provide a
summary description for. I'm presuming a solution here that I think is a
logical surmise. It's an interesting approach that a lot of people have
dismissed over the years. Sound cards are getting good enough (close to 100
dB dynamic range) that it might work. Clearly, this approach would have
been a disaster in the days when sound cards only had only 65 dB dynamic
range, or marginal with current cheapo-cheapo sound cards that have more
like 80 dB dynamic range.

"Arny Krueger" wrote in message
...
I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent
tests
that show how this unusual feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

I know the card has a greater dynamic range than vinyl, but are you saying
that what would come off the record would be reduced further or just that
the full range that the card has to offer would be reduced?

Thanks for the reply Arny!

"Arny Krueger" wrote in message
...
I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent
tests
that show how this unusual feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

I know the card has a greater dynamic range than vinyl, but are you saying
that what would come off the record would be reduced further or just that
the full range that the card has to offer would be reduced?

Thanks for the reply Arny!

"Arny Krueger" wrote in message
...
I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent
tests
that show how this unusual feature actually works.

Do you know if that dynamic range would be reduced to less that 80db?

I know the card has a greater dynamic range than vinyl, but are you saying
that what would come off the record would be reduced further or just that
the full range that the card has to offer would be reduced?

Thanks for the reply Arny!

Jimmy The Clam wrote:
As you have probably surmised from the title, this will be used for
transferring vinyl LPs to a digital CD-ROM format (16 bits and 44.1
kHz).

Turntable will be a Rega P-3 with a Rega Super Elys cartridge.

Here is my question:
I have a choice between an Echo Mia-MIDI or TerraTec DMX 6FIRE 24/96
sound card to do the AD conversion. With the DMX 6Fire I can run the
turntable directly into the break-out box and skip the Phono Pre amp
altogether and do the RIAA equalization in software. To me this looks
like a real attractive alternative to the more traditional approach of
Turntable Phono PreAmp Sound card. It also saves me $600 to $1,200
in cost which is pretty significant in my world. It also avoids all of
the problems that might be related to my PreAmp coloring the sound as
well (yes I'm thinking tubes).

I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent tests
that show how this unusual feature actually works.

Jimmy The Clam wrote:
As you have probably surmised from the title, this will be used for
transferring vinyl LPs to a digital CD-ROM format (16 bits and 44.1
kHz).

Turntable will be a Rega P-3 with a Rega Super Elys cartridge.

Here is my question:
I have a choice between an Echo Mia-MIDI or TerraTec DMX 6FIRE 24/96
sound card to do the AD conversion. With the DMX 6Fire I can run the
turntable directly into the break-out box and skip the Phono Pre amp
altogether and do the RIAA equalization in software. To me this looks
like a real attractive alternative to the more traditional approach of
Turntable Phono PreAmp Sound card. It also saves me $600 to $1,200
in cost which is pretty significant in my world. It also avoids all of
the problems that might be related to my PreAmp coloring the sound as
well (yes I'm thinking tubes).

I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent tests
that show how this unusual feature actually works.

Jimmy The Clam wrote:
As you have probably surmised from the title, this will be used for
transferring vinyl LPs to a digital CD-ROM format (16 bits and 44.1
kHz).

Turntable will be a Rega P-3 with a Rega Super Elys cartridge.

Here is my question:
I have a choice between an Echo Mia-MIDI or TerraTec DMX 6FIRE 24/96
sound card to do the AD conversion. With the DMX 6Fire I can run the
turntable directly into the break-out box and skip the Phono Pre amp
altogether and do the RIAA equalization in software. To me this looks
like a real attractive alternative to the more traditional approach of
Turntable Phono PreAmp Sound card. It also saves me $600 to $1,200
in cost which is pretty significant in my world. It also avoids all of
the problems that might be related to my PreAmp coloring the sound as
well (yes I'm thinking tubes).

I've got some concerns about the fact that the DMX's RIAA equalization is
done with software. Historically, this has involved some compromises in
terms of dynamic range. I can't find any detailed specs or independent tests
that show how this unusual feature actually works.