Home Speaker Asylum

General speaker questions for audio and home theater.

My experience

I've done a couple sub setups. Both used a VTL Deluxe preamp that has two sets of independent outputs (cathode follower to the mains, and 12AU7 buffered to the sub) and an old ACI Titan II LE powered sub.

1. Spica TC-50
For this, I put a series cap in the unbuffered output for a 6 dB/octave high-pass filter at 80 Hz. Integrating with the sub was pretty much seamless and very musical. To dial it in, I'd listen to the Spicas alone for a while, then turn the sub on and see if they lost any of opening/imaging/naturalness. If they did, the sub was too loud. I also used the old R/S SPL meter, with its well known bass rolloff, to double-check. If I got a measured flat response, that suggested I was at least not "sub heavy." Less is always more with subs.

2. Tannoy Stirling GR
The Tannoys are good to somewhere in the mid-40's (down 6dB at 39 Hz) so I did away with the series cap in the preamp, and set the sub for 12 dB/octave at 45 Hz. With this, the sub rarely puts out anything at all; I've been surprised at how little material there is down there. When there is material for it, such as "Turn Me On" from Nora Jones' "Come Away With Me" SACD, it adds a touch of the bottom end that the Tannoys miss. For the rest of that recording, the sub does nothing. As the Tannoys are extremely fast and airy, and have the best imaging I've ever heard, anything that impinges on that is a mortal sin. With almost all recordings, even played very loud, the sub does nothing.

For me, it's a matter of extending the range *if* it can be done without degrading the mains. With the Tannoys, there is almost no overlap, but for the Spicas, with their 6 dB/octave rolloff, there was quite a bit. (If "no overlap" is a requirement, then no sealed main speaker can ever be integrated with a sub.)

What we're doing when integrating subs is not much different from what a full-range speaker designer does - we're both using an LCR circuit to give a high-pass to the tweeter, and low-pass to the woofer. But, as we are adding an *additional* LCR circuit, plus power amp and driver, it's a matter of deciding if the additional stuff adds to the experience, or detracts from it. My best advice is to try it, live with it for a long time, and periodically check back with the sub turned off to see whether the it actually helps, or adds anything unwanted.



"A man need merely light the filaments of his receiving set and the world's greatest artists will perform for him." Alfred N. Goldsmith, RCA, 1922

Edits: 04/14/17

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  • My experience - Bill Way 08:19:34 04/14/17 (0)


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