StudioLive AI-series mixer 96 kHz over the onboard FireWire 800 interface

[Boswell]

I'm thinking once I bypass the onboard pre (insert a Neve pre) this also disconnects the rest of that channel going through FW to the DAW (SL Capture software).

Ignoring for a moment the balanced/unbalanced problem, if you wire the output of the external Neve pre-amp to the SL's insert return point, the SL will continue to route and function exactly as before, except that now that channel will be handling a mic or line signal from a different input device (the Neve). When connected this way, if you are tracking via the SL's FW interface to a DAW, then the SL is acting purely as an A-D converter, like a line-level audio interface.

The unbalanced nature of single-jack insert returns can be a problem when you are trying to feed them with quality pre-amps. We've had threads on this before, but basically you have a balancing problem and a level problem. Assuming the pre-amp has independent drivers for its + and - outputs, you need to use a cable wired to take the + signal from from the pre-amp's output jack or XLR to the ring connection of the mixer's TRS insert jack plug in order to carry an unbalanced signal into the mixer. However, top-range pre-amps tend to have either electronically-balanced or transformer-coupled outputs, and these need different wiring to take the output to the ring and sleeve (ground) of the TRS insert jack. Note that in both cases the tip contact of the insert TRS plug is left unconnected, as this is the send signal, i.e. the output of the mixer's internal pre-amp.

The nominal level at unbalanced insert returns is usually -2dBu, this being the 6dB reduction from +4dBu through loss of half the signal. Full-scale (FS) levels are typically 18dB higher than this. The -2dBu nominal figure can be an acceptable match to the output of many mid-range pre-amps when just a + output is taken. However, with electronically balanced or transformer-coupled outputs, not only will both of these will deliver the pre-amp's full range output into a balanced or an unbalanced load, but it's a frequent production requirement to drive these pre-amps into slight overload to take advantage of the sound of transformer saturation. In this case, you may be presenting something like a +32dBu peak signal to an insert point that has only 18dB headroom above a nominal level of -2dBu, i.e. +16dBuFS. It's time to reach for the in-line attenuators...

 

[pcrecord]

Very good point Boswell !

 

[Boswell]

If I follow correctly, you can put an external preamp to the line in but it will go through the preamp of the AI
To bypass the preamp of the AI you can put the external preamp to the return of the insert using an insert cable without using the send, or a special build cable that only have the return connection.
The question is, is there any circuitry after the insert point that can alter the audio quality? If you could choose to put the insert post fader, you would be sure of a clean path to the converter. But if it's pre-fader only, it goes through the EQ, pan and the fader. So the question remain; how much circuitry come to play after the insert point?

I would ask the Presonus that question, just to be sure.

Not really any need, as it's all clear from the [="http://www.avss.com/pdf/mixers/presonus/StudioLive-blockdiagram-web.pdf"]block diagram[/]. Top left corner shows the insert return feeding only the input buffer of the ADC.

Don't forget that on all digital mixers, the faders and EQ operate in the digital domain. There's no concept of an analog insert point that is post-fader or post-EQ.

 

[pcrecord]

Don't forget that on all digital mixers, the faders and EQ operate in the digital domain. There's no concept of an analog insert point that is post-fader or post-EQ.

Yeah, I don't know where my head was this morning!!

@Chris ;
Unless you are planning to sell your converters, I'd keep sending the high end preamps to those, combined with the direct outs of the AI.
Or start with comparing both setups to know which are the best converters and decide accordingly

 

[audiokid]

Thanks for all the info guys, I keep forgetting about stuff lately. Seems I don't retain half of what I read until I actually use something.
I remember our past conversation about overloading those inputs, now I get it.

[="http://recording.org/index.php?members/47983/"]@Chris[/] ;
Unless you are planning to sell your converters, I'd keep sending the high end preamps to those, combined with the direct outs of the AI.
Or start with comparing both setups to know which are the best converters and decide accordingly

I'm planning to do a few comparisons with this console so I'm basically getting ideas for the party.
The direct outs would be the way I would go when combining this for sure.

@Bos, you linked a few products before. I should buy a few to have on hand. Was it similar to the Shure? Do these effect the sound, or better yet, would they match up "close enough" from one to the next?

Are there recommended 8 in/out in-line attenuator bays or are they best built in singles?
http://www.shure.com/americas/produ...em-solvers/a15as-inline-switchable-attenuator
here for High Fi.
http://www.musiclinkav.com/store/in...s&flypage=flypage.tpl&product_id=722&Itemid=1

 

[audiokid]

duh. To answer my question, lots of info here:

http://recording.org/index.php?search/50884/&q=attenuators&o=relevance

Some detail on pads. http://www.uneeda-audio.com/pads/

 

[Boswell]

Apart from knowing that different sorts and values of attenuators are easily available, my feeling is that the thing to do is work out how your connections are going to be made. I would write down a table (or spreadsheet) with the models of pre-amps in the leftmost column, then in further columns their output configuration (unbalanced, floating, balanced, transformer etc), their maximum output level and the connector type. Leave columns to fill in with sort of connection and attenuation needed. Only when you have a handle on how the connections are to be made would I start to look at what attenuators to consider.

PS The Presonus documentation is largely very good, but I can't find any info on the clipping levels at the insert returns.

PPS You could share the spreadsheet with the rest of us here at RO - many others may find it quite useful!

 

[audiokid]

Wonderful info Bos, if you want to do this, we could upload it, or post it for everyone. I had no idea it was this detailed but like everything pro, the last 2% is 98 percent of the problem solved or the reason why we are doing it all in the first place.

I'm not clear if you need my input on a list of pre's I use though? My list of Pre's is dropping off like flies. My "go to" is the Millennia M-2b for value and I'm considering an HV-3D for wideband transparency. I love the SPL Premiums but in the last 1/4 of this year, I'm pretty sold on transformeless pre-amps. I know and respect the Millennia Media sound so am very curious how the SL and Xmax compare. It would be fun to let you all hear the difference between an $1800 vs $130 per channel comparison. High end transformerless does not sound sterile at all. I compare it to fine sheer silk over an HD picture.
I wish I had more time just to do all the fun stuff like this. I'd love to have an extension to this site where we demystify all the nonsense. Which is really where I am heading half the time.

What can I do to help?

 

[DonnyThompson]

I know and respect the Millennia Media sound so am very curious how the SL and Xmax compare.

I wouldn't think that would be all that tough to do, after all, you do have both, right?

Although I'm a bit curious as to why you would want to compare them...other than just for fun... an $1800 dollar pre with a $130 pre - I would expect there to be be a pretty big difference, as one would, considering the price difference.

I don't think that the XMax would sound as good as the Millennia. And, I don't believe the XMax is a bad preamp, either - I really like their transparency, and in that price range, or maybe even a bit above it, I think you'd be hard pressed to do any better than a Presonus or a Focusrite, because of her transparency and gain, but I wouldn't think either one would sound nearly as good as your Millennia, nor would I really expect them to.

Would you? (not being sarcastic... I'm serious with that question).

Let us know if you end up doing an A/B.

 

[audiokid]

I wouldn't think that would be all that tough to do, after all, you do have both, right?

Yes, I have the console now.

Would you? (not being sarcastic... I'm serious with that question).

Let us know if you end up doing an A/B.

Hopefully I get a good singer in here that will indulge me If not, I will do it with speech by me. That's all I really need for where I am going with this.

I can't imagine anything rivaling the M-2b size or silkness, its a pretty unique design in that it is a Transformerless valve topology, on big rails. But, I can imagine other pre's being contenders in a best suited for a particular texture shootout.
I'm curious to see how the PreSonus sounds if I narrowed the bandwidth on the M-2b to match a XMax size, then how the pre in a Prism Atlas compares. I'm not looking for texture. I am interested to hear how these three compare when I roll off to try and match the smallest "one" in the comparison . This is where I'm going with this.
If this makes any scene, I'm inclined to believe some of why we choose particular pre's (maybe more than we think) ,has something to do with bandwidth capture.

I'm thinking the M-2b would make a great room pre too. It seems the best mixes I get, or those that are the easiest to dial in, are when the room has the largest canvas to paint with. So, for those that don't get the whole HPF thing when mixing, your mix can only be as big as your captured canvas. I am of course, getting artsy fartsy here.

 

[Kurt Foster]

The XMax discrete-component preamplifier runs on power rails of 30V, which is around twice the norm for IC‑based designs, thus allowing the designers to build in more headroom. While excellent IC (Integrated Circuit) preamplifier chips are available, the best ones are quite expensive, and there's something endearing about the simplicity of a good discrete design. As is the case with the vast majority of discrete preamps, this one uses class-A circuitry, with a frequency response that's flat within ±0.5 dB from 20Hz to 50kHz, and only 3dB down at 150kHz. THD+N noise (unweighted, 1 kHz @ +4 dBu output, unity gain) is better than 0.003 percent, and the equivalent input noise (EIN) figure is ‑126dBu, with 55dB of gain and measured from 20Hz to 22kHz. The gain‑control range is 60dB, with maximum input signal handling capacity of +14dBu.

 

[audiokid]

I've read that one too, thanks for posting that Kurt.

We're told the SL pre's are the same as the Xmax but I'm also told that the AI Series sound better than the first Generation of StudioLive Consoles. Which has me scratching my head. (The mystery of 3 versions of Xmas pres).
I have nothing to compare between both versions now but I'm hoping Dave sheds some light on this in time. He has the first gen of StudioLives and is planning to upgrade?

Being said, it would be even more interesting to learn how the Xmas rack pre compares to the consoles too? Do they all sound different and why? All builds say they have the 30v rails.

 

[Kurt Foster]

are the XMax pres transformer balanced?

 

[audiokid]

are the XMax pre transformer balanced?

Good point, I think there is better of that on the AI. the first gen SL didn't have as good a PSU either. Maybe there is something to do with a "lack of" rather what the specs say.

How does the PSU effect balancing?

 

[Kurt Foster]

i've always been under the impression that PreSonus pres were transformer balanced ...... the very first ones used Jensens and they supposedly sounded better than later versions.

 

[DonnyThompson]

From what I've researched, XMAX is a Class A, discrete transistor design that does not use op amps.

According to Presonus, the Xmax pres in the studio/live desk are the exact same Xmax pres in the rack mount versions.

 

[Kurt Foster]

probably the same type of twin servo pre design with "improvements" that PreSonus has been making for years. a lot like the Hardy 990 pre only not.

 

[kmetal]

The eureka is transformer balanced.

I dunno, if they are the same Xmax pres through and through, it really proves hwhat most designers say that it's the overall design, not just one or two components, cuz I've used the Xmax pres in the SL, the 2ch, and the rack unit, and they perform differently. The older digimax being the worst, so maybe they have been making improvements in areas other than profits. Maybe. Prob not. It's probanly just due to the pres incorporation in a different overall design.