Archive for November, 2011

Reproducing the Live Event – How Loud is Loud Enough?

We audiophiles are obsessed with frequency response (FR):

  • Is that system “flat” to 20hHz?
  • How low will these speakers go? I *must* have 20hz!
  • There was a “BBC dip” in that Tannoy. No, I would call it a smile.
  • Urgh. Those speakers are waaarrrm.
  • And so on….

Even looking at the august Stereophile, keeper of the truth of measurements, we see JA focusing primarily on (for loudspeakers) impedance, FR, and time domain criteria.

What’s usually missing, often ignored, is the amplitude response (AR). How loudly will the system play distortion-free, and how softly? As any Lowther or horn fan would say, this dimension is also vital to producing the illusion of a live event.

Wait, you may say, everybody (including JA) publishes sensitivity data (dB/V for speakers, and dB gain for amps) and uses said data for buying decisions. True enough. But our present system of metrics makes it difficult to answer the original question regarding distortion-free amplitude envelope.

More fundamentally, before we even worry about what our own system can do, we might ask the question: how much is enough? How loudly (and softly) must my system play to reproduce “live levels”? (Assuming one cares. And BAAS members seem to have wildly disparate opinions on this point.)

While researching this issue in the context of my own system, I discovered an excellent survey article on the issue of audio dynamic range (click here). The source was a Greek website (unsurprising given the audiophile mania over there). I will warn you that the piece is long, winding, and – given the blazing red background – hard on the eyes. But it rewards the reader with a trove of cool data, from microphones to the digital chain and (eventually) out your speakers and into the room. Along the way, we investigate the noise floor of Davies Hall and Skywalker and more.

I’ll give you the gist. How much dynamic range do I need? More than you think. Can my present system do it? Almost certainly not. What can I do about it? Ummm, 24 bits, 500+ watts, multichannel….

Read the article. It’s a bit of work, but you’ll likely learn something new and useful.

Enjoy your Thanksgiving.

Bob

 

Thursday, November 24th, 2011 Audiophile, Bob, General, Technical Comments Off

Bay Area audiophiles meet the new Qol technology

This weekend offered something new few BAAS members, who were introduced to one of the first net-new technologies to hit the high-end scene in years. Of course, I’m talking about the Qol (think “coal” re pronunciation) algorithm from BSG Technologies.

Each of the three sessions began with a thorough briefing from BSG CEO Larry Kay. We then tested the transparency of the analog circuits in the Qol device. With Qol in a tape loop of the Wavelength preamp, we switched the unit in and out while playing the Mahler 2 from Classic. Not a single member could hear a difference. Nada. This in itself can be considered a fine accomplishment IMO. In fact, add an attenuator and a little gain to the Qol and a great preamp would emerge,

We spent much of the rest of the time switching the actual Qol processing in and out. This test was a bit tougher to interpret, as the nature of the Qol – adding (“restoring”) phase and harmonic information to the signal – results in a 0.5dB-2dB rise in acoustic power. So everybody heard a big and positive difference when the Qol was switched in. The question was how much of this goodness was due to the effect and how much do to the gain.

It’s not my role here to render a judgement. But I will say two things. First, BAAS members were unanimous that the Qol processing did no harm, i.e., the processed signal sounded at least as good as the raw signal. Second, one minute into the demo, an experienced BAAS listener sitting in the room’s sweet spot pronounced “I’m sure it’s doing more than a gain change!” Beyond that, I’d urge interested listeners to spend time with the unit themselves. (As I understand it, BSG has a reasonable home audition policy, at least in the Bay Area.)

All of our testing was supported by the new Triode loudspeakers from Jim Jordan of Vaughn. Jim also brought a stack of Wavelength electronics, which featured NOS Western Electric 300B tubes. The source was my highly-modified Pioneer Elite universal player.

Many thanks to Larry, Jim, and Shawn Herrara (local Qol dealer) for making the event a success.

Bob

Edit: The new issue of The Absolute Sound (#220) contains a seven-page rage of the Qol device by Robert Harley.

 

Monday, November 14th, 2011 Audiophile, Bob, Equipment, Events Comments Off

Where’s the dough in downloads? Ringtones!

Well, it’s nice to be HDtracks, Linn, or some other music download service. And it’s great to be Apple or Amazon – but not for their music download sales.

But being on top of ringtones? Now that rocks!

You may be surprised at the size of this market. Don’t be. Number of buyers is huge, size of sales channels (starting with cellphone companies) is huge, and most buyers just want the latest Ga Ga now and easily.

You might also be surprised at the movie and commercial soundtrack bizes too…but that’s another story.

Bob

Thursday, November 10th, 2011 Audiophile, Bob, General, Music, News Comments Off
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