SSL2+ Low Volume Direct Monitoring Vocals

[ef37a]

I just don't don't get this? It is the SAME headphones in use whether listening to a USB return signal or one from Direct Monitoring, assuming that is that the DAW and DM give overall unity gain?

I am 'de-rigged' atmo but I am PDsure I did not have this problem with my NI KA6 nor my 1st gen 8i6* but will get the KA6 live again if OP wishes me to test it.

PCBs can be 'wrongly stuffed'. All it takes is two SM resistor to be wrong in the DM signal feedback path...'it'appen.

*Nor indeed with any of the half dozen or so AIs that have come through my hands in the last 12 years AFAIR.

Dave.

[Drew Stephenson]

I can't remember if we've already covered this but have you contacted SSL and what did they say?

Hi Drew,

Yes I think briefly mentioned it earlier. SSL support came back with the two following responses...

Thanks, I thought you'd covered it.
Hmm. Whereabouts in the world are you? There may be someone nearby who can lend a second set of ears/thoughts?

[mr_nervouswreck]

I can't remember if we've already covered this but have you contacted SSL and what did they say?

Hi Drew,

Yes I think briefly mentioned it earlier. SSL support came back with the two following responses...

Thanks, I thought you'd covered it.
Hmm. Whereabouts in the world are you? There may be someone nearby who can lend a second set of ears/thoughts?

Hi Drew,

I'm in Melbourne Australia, no movement right now. Under a complete lockdown again!

I suppose the thing is, I know what I expect to hear in terms of levels and head room to achieve quality recording takes.I have been a professional recording artist for many years.

Of course Input Monitoring can be achieved through my DAW, but one would expect the SSL should cater for half decent direct monitoring levels, even with a cheap pair of of AKG-K52s. It's really not a big ask!

[James Perrett]

Given Trey803's post and your experience with other interfaces feeding the same headphones, I'd be tempted to contact your dealer and ask for a replacement. Dave may well be right - it certainly sounds like there is a problem with the link between the input amp and the direct monitoring control.

SSL's response was really disappointing though.

[mr_nervouswreck]

Given Trey803's post and your experience with other interfaces feeding the same headphones, I'd be tempted to contact your dealer and ask for a replacement. Dave may well be right - it certainly sounds like there is a problem with the link between the input amp and the direct monitoring control.

SSL's response was really disappointing though.

I'm going to do just that James, it's hard to believe that cans with an impedance of 32ohms, still there isn't sufficient monitoring level.

There are many good write ups regarding the SSL2+ and reviews. I would believe that if everyone was facing my challenge it would be quite apparent by now.

[Trey803]

Just to be very very clear

My opinions were based on testing with the mixer control ALL THE WAY turned to input. If you start blending in the usb output you will lose output volume from your input level. But all interfaces with a blend/mix control are like this.

If you are experiencing low output volume with your mixer set to input only then you may have an issue.

I would try another source such as a Bass or Guitar DI. Could this be an impedance mis-match between your mic and the SSL2+ pre-amps?

[mr_nervouswreck]

Just to be very very clear

My opinions were based on testing with the mixer control ALL THE WAY turned to input. If you start blending in the usb output you will lose output volume from your input level. But all interfaces with a blend/mix control are like this.

If you are experiencing low output volume with your mixer set to input only then you may have an issue.

I would try another source such as a Bass or Guitar DI. Could this be an impedance mis-match between your mic and the SSL2+ pre-amps?

Yes that's exactly how I have got it setup. Turned all the way to Input, and the phones set to max 10.

I just got another response from SSL Support stating this to confuse me further, after mentioning to them I had no luck with lower impedance cans. AKG-K52s

SSL supports latest response:

You'll notice in the article previously sent that for optimum performance, a typical ratio of headphone impedance to source impedance should be 8:1 or better, and that the output impedance is 10 ohms. 32 ohm headphones are still way outside of the optimal impedance value, and will more than likely also have similar issues as 250.

[ef37a]

"SSL supports latest response:

You'll notice in the article previously sent that for optimum performance, a typical ratio of headphone impedance to source impedance should be 8:1 or better, and that the output impedance is 10 ohms. 32 ohm headphones are still way outside of the optimal impedance value, and will more than likely also have similar issues as 250."

I have read every issue of SoS since Feb 2005 and it has only been in the last week or so that I have read of this concept of 'matching' headphones to amplifiers by some ratio. However, be that as it may it does not explain the difference between direct and replay volumes with the SAME phones. It also astounds me that a very respected brand would make an AI not optimised for perhaps THE most common impedance now found for headphones?

Then of course the whole headphone 'impedance/sensitivity/specification' situation is a mess. Many years ago there was a similar, not so wide, range of loudspeaker impedances. 'Pro' units were 15 Ohms (16 now) and domestic 'radio' speakers 3 Ohms. The coming of the transistor meant a gradual convergence to 8 Ohms and now the vast majority of passive speakers are nominally 8R. Of course, speaker designers have the 'luxury' of an assumed near zero source resistance from the amplifier (not valve guitar amps).
Perhaps one or more of the top headphone manufacturers would like to tell us what the optimum impedance of headphones would be?

Dave.

[James Perrett]

Perhaps one or more of the top headphone manufacturers would like to tell us what the optimum impedance of headphones would be?

It is interesting that Sennheiser choose 300 ohms for their high end headphones while Neumann, who are part of the same company, choose 150 ohms.

However, the difference in sensitivity between high and low impedance headphones may not be as great as you might think. I hope Craig Sawyers (a former technical director for Wharfedale) won't mind me quoting his post on headphone sensitivity from https://www.vintage-radio.net/forum/sho ... p?t=183009

Well, the sensitivity is down to the force factor, which is BIL. B is the magnetic field in Tesla, I is the current in amps and L is the length of wire. Of course the moving mass of the diaphragm is also relevant (though F = ma)

So assuming the B and m whatever they typically are for dynamic headphones, the sensitivity depends on IL. High resistance implies that L is large, so for a given sensitivity I has to be correspondingly low.

That is kind of a roundabout way of saying that the voltage sensitivity is likely to be similar to headphones of lower resistance.

[Trey803]

Are you capable of recording a screen video showing a few second of you singing into your mic and showing the input levels within your daw? If you need some help I could send you a link to a free chrome app that does it.

I often have similar issue when recording clean guitar with an SM57. The transients are so loud that to avoid clipping I am now so low I can't really hear the guitar that well. A compressor/limiter in this situation helps me to avoid the transients dictating a lower input level to avoid clipping.

The only way to really have a good sense of your input gain is for you to send a short video clip of your DAW's input level meter.

[mr_nervouswreck]

Alright so I've had a bit of time this afternoon to revisit and do some more troubleshooting around my 'Direct Input Monitoring' levels through the cans.

Turns out my AKG K52's which only arrived as a reference set of phones this week for this testing had a funny lead adapter. I swapped it for another adapter of mine and it seems to a little louder now, I should have checked this as soon as I got it.

I would say now when Direct Monitoring compared to the DT-770pro's, its about 30% louder to my ears when. Which is definitely an improvement.

I did an experiment plugging my Acoustic guitar into the SSL2, 'Direct Input Monitoring' levels seemed perfectly fine when turned up to around 70% cans volume.

Direct monitoring with my Microphone (NT1-A), it now seems better than before, however I still need the phones turned at least up to the 80% mark to get a decent level when tracking to hear myself well enough with the 'Monitor Mix turned almost all the way to the left to the 'Second Dot'.

I'm curious if turning my phones all the way up to 100% for example, should it be deafening loud when input monitoring my Microphone through my cans? For me that's certainly not the case, I guess it's loud enough now, but certainly no head room to really pump it, unless I turn up the gain, but that would result in clipping.

As I mentioned before, 'Playback USB Monitoring' has heaps of level and having the phones turned all the way up would be deafening.

Another experiment I did with 'Direct Input Monitoring' was having the audio coming out of my Monitors instead, turning the 'Monitor Mix Knob' up to about level 5, when singing through my microphone I had plenty of level and turning it up further was getting too loud.

I suppose I'm still a little unsure as to what sort of levels should I be expecting from the SSL2+ in terms of real world Direct Input Monitoring? Is what I'm experiencing normal and within the limitations of the hardware? Definitely a little confused now with all the tests.

So to recap:

- Input Monitoring with my Microphone, I need to have the cans turned up anywhere between 80%-100% mark have decent enough levels to record and hear myself well enough.

-Input Monitoring with my Microphone, with audio coming out my 'Monitors' is plenty loud, lot's of headroom.

-'Playback USB Monitoring has plenty of head room and volume.

p.s (My Microphone level readings are between -40db & -10db. Mostly hovering around -20db and peaking at -10db.

[James Perrett]

p.s (My Microphone level readings are between -40db & -10db. Mostly hovering around -20db and peaking at -10db.

Those are sensible levels - don't be tempted to follow SSL's advice to turn them up.

[mr_nervouswreck]

p.s (My Microphone level readings are between -40db & -10db. Mostly hovering around -20db and peaking at -10db.

Those are sensible levels - don't be tempted to follow SSL's advice to turn them up.

Yep I'll be leaving the levels as they are. I would love anyone else with an SSL2 to chime in as what I'm experiencing is normal for the hardware.

[Bob Bickerton]

As previously mentioned, what you describe is replicated on mine.

Of course, what your perception is 'loud enough' could well be different to mine!

Bob

[mr_nervouswreck]

As previously mentioned, what you describe is replicated on mine.

Of course, what your perception is 'loud enough' could well be different to mine!

Bob

Thanks and sorry to reiterate this again.

During your tests did you try 'Direct Input Monitoring' using a Microphone?

Did you generally need to have your 'Phones' set to about 80%-100 % to have enough monitoring volume?

At that level for me personally the 'Direct Monitoring' had enough volume but was far from what I would describe as deafening loud, more akin to a comfortable level without any headroom. Once turning the Input knob slightly to blend to blend the track with the input, the level was even less.

Would you concur Bob your experience was somewhat similar?

[ef37a]

Hmm, I hope we get a clear resolution to all this and a comprehensive answer from SSL would be most welcome.

I had promised myself an M4 next year but I might just go for Mk ll KA6?

....BUT! I DO like that 'loopback' trickery!

Dave.

[Bob Bickerton]

OK, I've set up the SSL 2 again and recorded some stuff.

I'm using Logic on a Mac Mini and I recorded stereo acoustic guitar and then tracked vocals against that using a Microtech Geffel UMT-70S. I was monitoring on Beyer DT770 - 80Ohm headphones. I had the SSL plugged directly into the computer (no USB hubs).

The guitar was recorded with a target level of -15dBFS and had peaks of around -10dBFS.

The vocals were recorded with a target level of -15dBFS and had peaks around -12dBFS.

Here's a photograph of my setup when recording vocals:



As you can see I had the headphone level on full and the monitor mix at around 10 o'clock.

I would regard the level in the headphone as barely workable - certainly minimal. Whilst I don't monitor particularly loud, I do like my vocal monitoring to be sufficiently loud as to ride above any vocal bleed and internal head resonances - this was not achievable with the SSL.

So in conclusion, I think what you've described is not a fault, but a design issue and, to be frank, I'd suggest the unit is not fit for purpose for your application.

Having said that, it is fit for purpose for the application I use it for, namely backup recording on location and as a monitor controller.

The solution, apart from sending it back, would be to drive a (decent) headphone amp off the speaker outputs. However, if you're using it for tracking, the lack of comfort reverb may be an issue.

Probably not what you want to hear - but that's my call on it.

Bob

[ef37a]

Oh dear! I said "M4" didn't I? Please excuse an old, daft, meds ridden valve amp jockey.

It IS the M4 I am thinking of. I did consider the SSL2+ but then realized that it does not have two extra line inputs? Foot, shot IMHO.

Dave.

[mr_nervouswreck]

So to add a little confusion to it all, my latest message to SSL and their response. What to believe? Normal Headphone Amp Limitations of the SSL, or a hardware fault?

See below:

My latest email to SSL:

Hi Kyle,

I've had a slight improvement, the adaptor for my AKG-K52s was a little funny, I seem to have a little more level now.

However when vocal monitoring using my Microphone I need the Phones Level almost at 10 to get decent level when recording to track is that to be expected?

When Input Monitoring and the audio coming out of my Active Monitor I have much more level when adjusting the Monitor Mix.

I have also tried a different usb cable and laptop, same results.

I guess I'm rather confused now, I just feel there should be more volume/headroom so to speak to when recording through my Microphone. But perhaps it's the limitations of the SSL2 design?

If you happen to have a Unit to test, I would be curious to hear what your levels are set at to achieve good Direct Monitoring levels when using a Microphone. For example if you set i the Monitor Mix to input and the phones to 10 max, is your microphone extremely loud or deafening so to speak? Of course within the parameters of normal gain levels -10db to -40db

SSL'S Email Response:

Hi,

Thanks for the info.

Everything is testing as expected on our end.

It's possible your unit is defective. Can you send a screenshot or photo of a receipt or proof of purchase for your interface?

Best regards,

[Bob Bickerton]

You could waste a lot of time and money sending it back for assessment and being told there's nothing wrong with it. You have described exactly what I have described (though subjective terms such as deafeningly loud are meaningless).

If you can send it back to the supplier for a refund or credit I would do that now.

Bob

[mr_nervouswreck]

You could waste a lot of time and money sending it back for assessment and being told there's nothing wrong with it. You have described exactly what I have described (though subjective terms such as deafeningly loud are meaningless).

If you can send it back to the supplier for a refund or credit I would do that now.

Bob

Yeah you are right Bob, the only difference being with my NT1-A the gain is turned down one notch to the left, otherwise I would be in clipping territory.

I do actually love the sound of this little unit, I did some recording over the weekend, Direct D.I Guitars and Vocals, it does sound a lot more fancier than the price would suggest.

How would I go about running a Headphone Pre-Amp into it? Do simply wire it into my Headphone inputs, and have the phones plugged into the pre-amp?

My retailer will most likely charge me a Re-Stocking fee I believe! Even then what other interface would be similar. I was thinking if anything the Audient iD4 Mkii, however my current dinosaur of a Macbook Pro does not have USB 3.0 to power it... Not sure if it would work!

I wonder if the Audient would capture similar sound to the SSL2?

[Bob Bickerton]

Just responded to a post in another thread related to this and, having looked at the SSL again, the issue is not so much headphone amp volume but an internal gain structure issue.

I said:

The problem is that the unit is designed to provide a balance between inputs and monitor mix when the input levels are at 0dBFS - and no-one records (or should record) at those levels.

Pull the input levels back to sensible -20dBFS to -15dBFS and you have a problem. You have to tweak the monitor mix way round to the input side or reduce your playback mix accordingly - either way you greatly reduce the signal being sent to the headphone amp.

So IMHO - a design issue.

In terms of what to suggest next - I wouldn't worry about the 'sound' of the unit - it'll be barely perceptible relative top other factors in your recording chain.

Finding a decent headphone amp will cost a lot more than an exchanged interface and unfortunately, I'm out of touch with alternative interfaces in that price range - maybe follow the new interface thread that's just started.

Bob

[Trey803]

Here is another YouTube review and basically saying the same as the OP

https://www.youtube.com/watch?v=Su2IUiV ... erCreative

[mr_nervouswreck]

Just responded to a post in another thread related to this and, having looked at the SSL again, the issue is not so much headphone amp volume but an internal gain structure issue.

I said:

The problem is that the unit is designed to provide a balance between inputs and monitor mix when the input levels are at 0dBFS - and no-one records (or should record) at those levels.

Pull the input levels back to sensible -20dBFS to -15dBFS and you have a problem. You have to tweak the monitor mix way round to the input side or reduce your playback mix accordingly - either way you greatly reduce the signal being sent to the headphone amp.

So IMHO - a design issue.

In terms of what to suggest next - I wouldn't worry about the 'sound' of the unit - it'll be barely perceptible relative top other factors in your recording chain.

Finding a decent headphone amp will cost a lot more than an exchanged interface and unfortunately, I'm out of touch with alternative interfaces in that price range - maybe follow the new interface thread that's just started.

Bob

Thanks Bob, my store is now adamant it's a fault in the hardware after testing an in-store unit. They have offered a full refund or a replacement unit.

I do agree with you that it's a design flaw rather than fault, I just can't believe there is not much talk of this anywhere?

All of the SSL2 reviews don't even touch on the Input Monitoring levels, but rather overall USB Playback levels, which leaves them to believe there is plenty of power to drive the phones in both aspects... This is surprising.

I don't think Head-Phone preamps are that pricey? Would something like this do the trick https://djcity.com.au/product/behringer ... gJyBvD_BwE

Either way perhaps it's worth swapping my unit over just in case mine is abnormally quite in Input Monitor Levels?

[shufflebeat]

CMoy

Have a read:

https://www.headphonesty.com/2017/03/cm ... ifier-kit/