Sig 30 with subwoofer

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lpgorbet

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Sig 30 with subwoofer
« on: 18 Nov 2006, 05:21 pm »
I have a pair of Gallo Solo's (the final, aluminum ball version) that I'm using with an SVS subwoofer. My room is small (roughly 13x14x8 feet, with some opening into other rooms), treated with Eighth Nerve corners and rectangles. I don't listen very loud (probably never above maybe 92 dB). The room and speakers etc. are pretty well tuned right now --- bass is really flat below 20 Hz except for a modest dip around 55 Hz.

Anyway, I'm wondering whether if there's any way to use the Signature 30 and have the output to the Gallos high-pass filtered (say around 80 Hz)? I ask because (a) it would, of course, make it easier on the Sig 30's; (b) I'm running the Gallos with a HT receiver (slightly modded JVC FZ10) with the output for them set to "small" cutting off around that frequency and the bass is a lot flatter than when I ran them full range. Or would any solution give up too much of what the Sig 30 has to offer, even assuming it was possible?

I suspect the Sig 30's *could* drive the Gallos full range just fine --- they're around 88-90 dB efficient and, although nominally 4 ohm, present a very benign impedance curve to amps. It would just mean some more room-juggling to try to get a smoother bass response.

Jampot

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Re: Sig 30 with subwoofer
« Reply #1 on: 18 Nov 2006, 08:39 pm »
I'm sure Vinnie will be along to impart his wisdom...

Presumably you had in mind to use the sig 30 pre- out to the sub and then filter the output to the Gallos from the speaker terminals.

Does the JVC have pre-out?
Unless the JVC is compromised in the pre amp stages perhaps you could could continue to use the built in frequency filtering...

Vinnie R.

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Re: Sig 30 with subwoofer
« Reply #2 on: 19 Nov 2006, 01:39 pm »
Hi lpgorbet,

Welcome to Audiocircle and the RWA forum!

First, if you are looking to use a subwoofer with the Signature 30, you need to use the Sig 30s volume controlled RCA output jacks.  Connect these to the RCA input jacks of your sub.

Will you be using a speaker switch box to switch between the HT receiver and the Sig 30?

Regarding filtering the bass, you can try installing a capacitor in series with the positive terminals of the speakers (for a 1st-order, 6dB/Octave rolloff).  I would definitely try it full-range... the Sig 30 will have no trouble driving them.

Best regards,

Vinnie






Lesved

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Re: Sig 30 with subwoofer
« Reply #3 on: 20 Nov 2006, 08:50 am »
Correct me if I'm wrong, but listening at a SPL of 92dB with 88dB speakers and with, let's say, 16dB of headroom, you will need an amplifier with at least 200 Watt when the impedance drops to 4 Ohm. Dynamic orchestral music may demand 25dB of headroom, i.e. about 1700 Watt (all else equal). This means you ought to choose a loudspeaker with a sensitivity of 93dB for a headroom of 16dB, or one with 102dB for a headroom of 25dB.

Vinnie R.

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Re: Sig 30 with subwoofer
« Reply #4 on: 20 Nov 2006, 12:47 pm »
Hi Lesved,

Welcome to Audiocircle and the RWA forum!

Quote
I don't listen very loud (probably never above maybe 92 dB).

I'm not so sure if lpgorbet knows how loud he really listens to.  92dB peaks?  92dB average?  Was a calibrated SPL meter used? 

Quote
I suspect the Sig 30's *could* drive the Gallos full range just fine --- they're around 88-90 dB efficient

Yes it can... especially in such a small room.  I doubt there is need for a 200 watt amp  :wink:

Best regards,

Vinnie

Alwayswantmore

Re: Sig 30 with subwoofer
« Reply #5 on: 21 Nov 2006, 02:51 am »
Anyway, I'm wondering whether if there's any way to use the Signature 30 and have the output to the Gallos high-pass filtered (say around 80 Hz)?
I run my Signature 30 using a Vandersteen X-2 highpass filter. X-2s are placed in series using the interconnect cable. The X-2 is designed to be used with a Vandersteen sub, but its function may still serve your needs.

The X-2 must be matched to the input impedance of the Signature 30 (20K ohms). And it is designed to attenuate lower frequencies before they enter the amp. 80Hz is the crossover point, and they roll off at 6 db per octave. X-2s sell for about $150 new, and sometimes you find them used on Audiogon for about $75.

Here is a link to one that I am selling so you can see what they look like (DO NOT BUY THIS ONE, YOU NEED 20K OHMS FOR THE SIGNATURE 30)... http://cls.audiogon.com/cgi-bin/cls.pl?homesubw&1168033983

Vinnie R.

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Re: Sig 30 with subwoofer
« Reply #6 on: 21 Nov 2006, 01:22 pm »
Hi Alwayswantmore,

Welcome to Audiocircle and the RWA forum!

(Alwayswantmore is my first customer who purchased his Signature 30 for use with AKG K1000 headphones.  He posts and blogs a lot on www.headfi.com.)

Quote
The X-2 must be matched to the input impedance of the Signature 30 (20K ohms). And it is designed to attenuate lower frequencies before they enter the amp. 80Hz is the crossover point, and they roll off at 6 db per octave. X-2s sell for about $150 new, and sometimes you find them used on Audiogon for about $75.

Sounds like that all they are is a series capacitor in between an RCA male and female jack  :wink:

NOTE: If you do use this, then the RCA output jacks on the Sig 30 will also be high-pass filtered, as these jacks are the input signal that passed through the DACT CT2 volume control. 

Cheers!

Vinnie





lpgorbet

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Re: Sig 30 with subwoofer
« Reply #7 on: 23 Nov 2006, 05:18 pm »
Vinnie wrote

"Will you be using a speaker switch box to switch between the HT receiver and the Sig 30?"

No. Actually, I don't use the receiver for "real" HT --- just two front stereo channels plus the subwoofer --- so I'd be using the Sig 30 full time. I currently run satellite TV and my VCR through it, but I'd probably just route those to the TV until I got a 30S or other way of switching Sig 30 input. In short, I'd be aiming to get the most I can from what the Sig 30's offer, especially for music.

"Regarding filtering the bass, you can try installing a capacitor in series with the positive terminals of the speakers (for a 1st-order, 6dB/Octave rolloff).  I would definitely try it full-range... the Sig 30 will have no trouble driving them."

Sounds like a good idea. I discovered with a more careful check with a calibrated meter that I was indeed conservative about my maximum listening level in my first post. It's more like 87-90 dB at the extreme. I've never checked how the volume readout actually works on my receiver, but it goes to "50" and nominally outputs 100 wpc at 6 ohms; my max is about "30". Maybe I'll spend some time this weekend doing more placement experiments do see if I can flatten out the bass from my main speakers. That would be a win no matter what I eventually do.

Best,
Larry

Vinnie R.

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Re: Sig 30 with subwoofer
« Reply #8 on: 25 Nov 2006, 12:32 am »
I've never checked how the volume readout actually works on my receiver, but it goes to "50" and nominally outputs 100 wpc at 6 ohms; my max is about "30". Maybe I'll spend some time this weekend doing more placement experiments do see if I can flatten out the bass from my main speakers. That would be a win no matter what I eventually do.


Hi Larry,

I get calls and emails regarding "will it be loud enough?" and "I normal set my volume on my current amp to X o'clock..." , etc.  I have to jump in and mention this:

Volume controls vary from one make/model to the next...ie, their attenuation curves are all different.  Also, gain settings (and input sensitivity) on amplifiers vary from one make/model to the next. 

So I may have a 10 watt amp that at 11 o'clock on the volume control, it plays a lot louder than a 200 watt amp at 11 o'clock on the volume control. 

As long as you have enough head room to drive your spekears as loud as you ever wish to play them, that what is important.  I do believe that it is also nice to have a good range of use out of the volume control.  If the volume knob goes from 6am (mute) to 5pm (max), it is nice if the volume isn't too loud at, say, 10am.  You want to be able to have more range so you can more precisely set the volume.  I hate "hair-trigger" volume controls.  Of course, the sensitivity of the speakers come into play as well  :wink:

Quote
Maybe I'll spend some time this weekend doing more placement experiments do see if I can flatten out the bass from my main speakers.


You can tune the sound of a system a whole lot by just doing placement experimentation, so good idea! :idea:

Keep us posted!

Vinnie