Hi,

Thinking about buying a pair of BeoLab 9's. My setup will be playing from a dedicated laptop (streaming music services) and my questions is: is there anything I should be aware of in this setup? I have had other BL's connected to things like an AppleTV previously and this is a showstopper for me because the ATV opens up with a startup tune that plays full volume and as there is no way of controlling the BL9's and other BL speakers you can't really use it as the startup volume goes out full blast.

If I put an amplifier in between, the point of the BL9's sort of disappears a bit.

Any recommendations? 

With the proper cable adapters you should have no trouble running the 9's off of a laptop computer, the laptop's volume control will provide the management you need. 

While in the case of the ATV it has no volume control of its own, as it expects to be used asa source in some sort of larger A/V system, so I can't pretend to be surprised at the result any more than with most CD/DVD/Blu-Ray/Cassette/8-track players.

I'm a little skeptical of set-ups where one connects straight from the analog minijack out of a Mac to BL speakers with built-in amp's. There are various issues - one being the impedance scratching when you connect or disconnect the minijack, unless you have the speakers off. Another being the booms of sound that go through to the speakers on occasion, as you are racing for the volume control on your laptop.

I would recommend having a unit between the laptop and the speakers. That could be a B&O audiomaster, or maybe preferably a Digital-to-Analog converter, DAC, with volume control. Then you can have the volume control of this unit be your volume limiter, while you also avoid any impedance scratching that could damage your tweeters.

Using a DAC, you would also get better sound. Laptops are compromised by their power supply. Here's a measurement Cambridge did of jitter to their DacMagic, using a laptop running with power supply connected.

Here's what this measurement looked like when the laptop was running off its internal battery.

This was with the DacMagic using the USB connection, in other words there was a wired connection from the source (the laptop) to the digital-to-analog converter, and this solid connection transmitted the power supply noise and distortion. The small DAC inside the Mac used for this measurement does not outperform the DacMagic, of course, and is what would be delivering a signal to your speakers if you use the minijack out directly to the speakers.

Your BeoLab 9s deserve better.

The first trick is to either create a galvanic separation, that is to ensure that there isn't a solid connection between the laptop/Mac mini and the speakers. You can do that by using the optical out signal, through the same minijack connection (if you have a Mac laptop), or by streaming to an Airport Express unit, and then using the optical out of that.

Here's what the measurements above looked like when they used the optical out Toslink instead of the USB:

The power-supply induced distortion is gone.

You can also use firewire from a Mac to a stand-alone DAC. Most such units used in music production will use the built in jitter elimination of firewire transfer (a simplistic way of putting what happens) to ensure the integrity of what's ported from the laptop/Mac mini.
Mattybass asked a question over at the Vintage-forum which is relevant here - he wanted to connect through his Edirol DAC to a Beocenter 7000; but in your case you could use such a unit to connect to the BL9s. Just get an RCA>PL cable, and connect that instead of the RCA>DIN cable that mattybass will be using.

http://forum.beoworld.org/forums/t/34230.aspx

It remains an absolute mystery to me that B&O has not done what Roland and others have done, as exemplified through the product below. This is a compact firewire enabled unit which takes the CoreAudio feed out of a Mac, and which can be used as a preamplifier to active BeoLab speakers - with a B&O skin such a unit would be heaven sent, could easily be integrated with other B&O kit, and would recruit young consumers in droves when they discovered what active speakers can do. (And you also get a very good headphone amplifier ...)

http://www.roland.com/products/en/FA-66/

How audible is the USB jitter noise/distortion?

Hey Soundproof,

Thanks for the answer, it was exactly the sort of thing I was hoping for. Indeed, the BL9's "deserve better" and you have highlighted the sort of issues and options I can go for. 

I haven't finally decided on the BL9's - and was designwise tempted more by the BL 6000's. Would the same point above apply to those speakers?

Puncher:

How audible is the USB jitter noise/distortion?

Good question, Puncher. Tests have shown that jitter has to be in the 250nanoseconds range before it is audible. HiFi-publications will of course scoff at this, as quite standard gear delivers performance in the picoseconds ranges.

However, there's little doubt that a laptop with a power supply is a noisy environment for audio, and that it might be worthwhile to make an effort to get the best possible signal out of the unit - which means having a galvanic separation through optical or using CoreAudio porting where possible, with FireWire.

A more relevant point is the fact that connecting BL9s to the analog minijack out of a Mac really does the speakers a disservice.

Any of the B&O active speakers can be used in this manner, of course, and the BL6000s are a good choice. My preferred computer speakers are the BL4000s - but if one wants a really top notch playback system, then connecting B&O's active speakers to a good DAC is an excellent choice.

soundproof:

Puncher:

How audible is the USB jitter noise/distortion?

 

Good question, Puncher. Tests have shown that jitter has to be in the 250nanoseconds range before it is audible. HiFi-publications will of course scoff at this, as quite standard gear delivers performance in the picoseconds ranges.

However, there's little doubt that a laptop with a power supply is a noisy environment for audio, and that it might be worthwhile to make an effort to get the best possible signal out of the unit - which means having a galvanic separation through optical or using CoreAudio porting where possible, with FireWire.

A more relevant point is the fact that connecting BL9s to the analog minijack out of a Mac really does the speakers a disservice.

Any of the B&O active speakers can be used in this manner, of course, and the BL6000s are a good choice. My preferred computer speakers are the BL4000s - but if one wants a really top notch playback system, then connecting B&O's active speakers to a good DAC is an excellent choice.

 

 

Agree.

A Stereophile  review said, "Although its USB input is really of only utility quality and shouldn't be used for serious listening, the Cambridge Azur DacMagic otherwise offers superb measured performance", which I thing is way over the top, the sidebands they measured using USB with a constant frequency modulation were ~ -103dB..................I detect a hint of bias!

They should be made to draft their listening "findings" blind and then publish the week before the measurements are made.

I am affraid to ask: but will this work equally well with a PC being the laptop?

Yes, it should. You may want to check that the DAC you use has a good interface to a PC, but the Edirol DAC mentioned in the link communicates well with both PC/Windows and Apple/OSX.

You can also stream from a laptop to an Airport Express unit, which is then connected via optical Toslink to the DAC.