RME ADI-2/4 Pro SE - RIAA mode measurements

[MC_RME]

Note that Mono Bass has zero effect on frequency response with a stereo test signal that is fully identical L/R (mono). This is not the case here, obviously (reason unknown).

 

[Erogen]

you started off with near perfectly flat cartridge response from 50 to 500hz and ended up creating a 5db slope…

RME (user manual)

"Turntables are mechanical trackers and therefore generate a variety of unwanted sounds: low-frequency rumble, microphone effects, the sound of the stylus in the groove, and, of course, the characteristic crackling noise caused by dust. The ADI-2/4 Pro helps keep these lateral sounds under control.
First, an astonishing effect: when you switch playback to mono, susceptibility to acoustic feedback, low-frequency rumble, and groove noise are significantly reduced. Because no one wants to listen to records in mono, and the bass on vinyl is mono anyway for manufacturing reasons, the ADI-2/4 Pro SE includes a mono mixing circuit that only mixes the bass section. RIAA Mono Bass, available in the Analog Input menu, causes virtually no change in the sound but significantly reduces background noise.
With unusually high bass, especially when combined with loudness and a quieter LP, the rumble visible in the low bands can reach the same level as in the other bands when listening to music."

 

[Bland_username42069]

RME (user manual)

"Turntables are mechanical trackers and therefore generate a variety of unwanted sounds: low-frequency rumble, microphone effects, the sound of the stylus in the groove, and, of course, the characteristic crackling noise caused by dust. The ADI-2/4 Pro helps keep these lateral sounds under control.
First, an astonishing effect: when you switch playback to mono, susceptibility to acoustic feedback, low-frequency rumble, and groove noise are significantly reduced. Because no one wants to listen to records in mono, and the bass on vinyl is mono anyway for manufacturing reasons, the ADI-2/4 Pro SE includes a mono mixing circuit that only mixes the bass section. RIAA Mono Bass, available in the Analog Input menu, causes virtually no change in the sound but significantly reduces background noise.
With unusually high bass, especially when combined with loudness and a quieter LP, the rumble visible in the low bands can reach the same level as in the other bands when listening to music."

“low frequency rumble”

 

[Erogen]

Note that Mono Bass has zero effect on frequency response with a stereo test signal that is fully identical L/R (mono). This is not the case here, obviously (reason unknown).

The cause of the drop is known (frequency response 500Hz-50Hz), and that's how the default mono-bass filter in the RME 2/4 Pro SE works. Perhaps the mono-bass filter is poorly designed?

 

[Bland_username42069]

The cause of the drop is known (frequency response 500Hz-50Hz), and that's how the default mono-bass filter in the RME 2/4 Pro SE works. Perhaps the mono-bass filter is poorly designed?

No. it’s you

 

[Erogen]

No. it’s you

No, that's not me Probably not me
When using the Mono Bass filter, the EQ isn't enabled.
If we turn off the mono bass, there's no dip in the 50Hz-500Hz range, but if we turn on the mono bass, there's a dip in the 50Hz-500Hz range.

Someone else would have to verify this.

 

[MC_RME]

Check your test signal, channels L/R might be a bit out of phase. Maybe it is like that on the test record, or there is something else not set correctly. Mono bass does have zero deviation for mono signals.

 

[Bland_username42069]

No, that's not me Probably not me
When using the Mono Bass filter, the EQ isn't enabled.
If we turn off the mono bass, there's no dip in the 50Hz-500Hz range, but if we turn on the mono bass, there's a dip in the 50Hz-500Hz range.

Someone else would have to verify this.

none of your tests you have shown have mono on, eq off (unless I am blind which cannot be ruled out)

 

[Erogen]

none of your tests you have shown have mono on, eq off (unless I am blind which cannot be ruled out)

 

[Bland_username42069]

View attachment 513496

View attachment 513497

All monobass is doing is summing the two channels to mono. It does not do what you are showing. Either you did the test wrong or you have a problem further up the chain

 

[Erogen]

All monobass is doing is summing the two channels to mono. It does not do what you are showing. Either you did the test wrong or you have a problem further up the chain

It should only sum (theoretically), but there's also a dropout in the 500-50 Hz range.
1. That's how this filter works.
2. My RME unit is faulty, strangely enough, only in this case
3. I performed the test well.

I bet $1 that this filter is designed that way.

 

[Bland_username42069]

It should only sum (theoretically), but there's also a dropout in the 500-50 Hz range.
1. That's how this filter works.
2. My RME unit is faulty, strangely enough, only in this case
3. I performed the test well.

I bet $1 that this filter is designed that way.

Do as RME say and check to see if your cartridge is out of phase

 

[JP]

Note that Mono Bass has zero effect on frequency response with a stereo test signal that is fully identical L/R (mono). This is not the case here, obviously (reason unknown).

Typical FR sweep track - stereo cut with one channel modulated per sweep.

 

[Erogen]

Do as RME say and check to see if your cartridge is out of phase

Replacing the audio cables from the turntable to the RME, replacing the headshell, replacing the cartridge does not change anything, the 500 Hz 50 Hz drop still occurs.

 

[JP]

The clue is in how the fundamental and crosstalk converge. Bass summing typically assumes content in both channels.

 

[Bland_username42069]

Replacing the audio cables from the turntable to the RME, replacing the headshell, replacing the cartridge does not change anything, the 500 Hz 50 Hz drop still occurs.

It could be that your cartridge is not aligned properly.

Run a stereo test tone from your test record and see if the two channels are in phase.

 

[Erogen]

The clue is in how the fundamental and crosstalk converge. Bass summing typically assumes content in both channels.

How to understand?

 

[JP]

How to understand?

The test record has a signal in the left channel and nothing in the right channel. Then it has a signal in the right channel and nothing in the left. So the summing is working fine considering the abnormal scenario in which you're applying. The issue isn't the RME, it's your test methodology.

 

[MaxwellsEq]

Replacing the audio cables from the turntable to the RME, replacing the headshell, replacing the cartridge does not change anything, the 500 Hz 50 Hz drop still occurs.

You are using a test record. It has bass fully left panned, nothing on the right. Then it has bass fully panned to the right, nothing on the left.

What do you think is going to happen if you average a value of 1 and a value of 0? This is why your graph does not happen with genuine bass instruments (which are mostly mono-ed and mixed in between left and right).

Your graph does no show correct low frequency mono-ing.

 

[Salt]

Just skip that Test-Vinyl and test with REW with adequate attenuation of in/output signal.