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A quick word on subwoofers...


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I'm sticking to my guns.

I can't see any adantage in sending a high-level signal meant to drive a speaker to be attenuated to line-level before being re-amplified again.

I see high-level inputs as a work around the absence of sub outs in stereo pre-amps and integrated amplifiers. Ultimately convinence trumps performance though.

It makes sense for manufacturers to promote high-level, it's the only way that they can sell subs to the 2-channel crowd...

Edited by tuga
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Two subs are better for near-field listening but a well positioned and dialled in single sub in a domestic environment can be great fun. 

I've had plenty of speakers that don't 'need' a sub, some that defintely do... but never any that aren't improved by one. Provided it's effect is almost inaudible. I've got just one, and it's the way

Thanks and nice one  Glad you're enjoying the benefits of a sub/sat system  Even if the mains go down to 20Hz a subwoofer should be incorporated because ime a subwoofer can inject power into a sy

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On 07/04/2021 at 17:37, dannybgoode said:

No, as per the above you don't need an a dedicated crossover apparently. I don't have one and it does free up the mains as described. 

I am not technically minded enough to understand it :)

Ime, if using line level in particular then to do the job effectively using a dedicated in built or an external crossover is essential. And in the main using a low crossover point wastes the potential benefits of a subwoofer. Better to unburden the mains as much as possible and pass the LF burden onto the subwoofer to deal with. Using a low crossover frequency can negate a lot of the performance gains. Fwiw, I generally find 90Hz to be the sweet spot :)

The goal is to effectively aligned/calibrated/dialled in a subwoofer so that the subwoofer integrates seamlessly with the mains and disappears into the soundstage with a deep, sharp, tight fisted, fast and powerful punchy sub bass. image.gif.f1ff61f488fcec76c4ca81d307159dce.gifGet it right and a subwoofer can make the most profound difference to the overall performance of the system. 


 

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"Almost everything you ever wanted to know about subwoofers" by former JL Audio engineer Barry Ober:

http://www.soundoctor.com/whitepapers/subs.htm

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Someone made a list of amps designed to work with subs...

Stereo amplifiers with proper support for subwoofers by Thorbjørn Sigberg of Siberg Audio:

https://www.sigbergaudio.no/en/blogs/news/stereo-amplifiers-with-proper-support-for-subwoofers

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Gosh, there are a lot of bass modules out there parading as subwoofers....

Sheep in wolves' clothing!

Edited by Nifkin
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On 08/04/2021 at 11:58, tuga said:

Are you high-passing the signal into your woofers? Do the amps on your woofers know that subs are being used?

(or are they reproducing the full range signal and thus still running as hot as usual?)

Crossovers in the pre amp so the bass channel goes through the subs unaltered and the subs take a 60Hz low pass signal.

The sub 380Hz passed through then all  goes to the woofer power amp.

The amp does run cooler, helped by the Room Perfect cutting the output in bass to allow for the extra power from the subs.

I can switch the subs to an anechoic room eq setting for silly cinema bass.

The subs ended up slightly forward of coplanar wrt the woofers on 0 phase adjustment as they sit just outside the mains.

At those frequencies the bass sources seem to function well as one combined source.

I won't be offended if you think it shouldn't work!

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2 hours ago, timmytiger said:

The amp does run cooler, helped by the Room Perfect cutting the output in bass to allow for the extra power from the subs.

Are you high-passing the signal which goes into the mains?

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1 hour ago, tuga said:

Are you high-passing the signal which goes into the mains?

That's right,  tweets and mids are on another power amp channel over 380 Hz.

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Just now, timmytiger said:

That's right,  tweets and mids are on another power amp channel over 380 Hz.

That's what I have been advocating.

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11 hours ago, tuga said:

That's what I have been advocating.

Did you ever try a sub in your own system? I remember you saying that you wanted more bass than your Stirlings could manage.

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2 hours ago, savvypaul said:

Did you ever try a sub in your own system? I remember you saying that you wanted more bass than your Stirlings could manage.

I have though about it often.

Adding subs has the advantage of producing a more even response at the listening spot but I can't get around the practical disadvantages which are cost, lack of space, more cables, a dedicated preamp or integrated or an extra DAC.

Like I said in an earlier post the RME is a DAC-preamp and it allows one to use both analogue outputs simultaneously. It is not ideal because I cannot high-pass the mains and I would have a preamp feeding and integrated, but it is doable.

Another downside is that I am using the RME DSD Direct mode which bypasses the DSP module and thus the signal is going as DSD straight into the D/A stage. It is how the DAC measures and sounds best. But in order to use the volume control the signal would have to go through DSP, so I'd need to have HQPlayer oversample my CD rips to PCM768 instead of DSD256 which doesn't measure or sound as good.

But the worst part would be finding floorspace for two subs. They'd have to be at least 10" or 12" or a pair of particularly high-performance smaller models which would probably be very expensive.

So I will probably end up getting floorstanders in spite of the disadvantage in terms of low end flatness... For the time being they're fine, it's only with complex orchestral music that I find the need for more extension. Our current sitting room is quite small and I may as well wait until we move before getting a pair of mammoths.

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4 hours ago, tuga said:

I have though about it often.

Adding subs has the advantage of producing a more even response at the listening spot but I can't get around the practical disadvantages which are cost, lack of space, more cables, a dedicated preamp or integrated or an extra DAC.

Like I said in an earlier post the RME is a DAC-preamp and it allows one to use both analogue outputs simultaneously. It is not ideal because I cannot high-pass the mains and I would have a preamp feeding and integrated, but it is doable.

Another downside is that I am using the RME DSD Direct mode which bypasses the DSP module and thus the signal is going as DSD straight into the D/A stage. It is how the DAC measures and sounds best. But in order to use the volume control the signal would have to go through DSP, so I'd need to have HQPlayer oversample my CD rips to PCM768 instead of DSD256 which doesn't measure or sound as good.

But the worst part would be finding floorspace for two subs. They'd have to be at least 10" or 12" or a pair of particularly high-performance smaller models which would probably be very expensive.

So I will probably end up getting floorstanders in spite of the disadvantage in terms of low end flatness... For the time being they're fine, it's only with complex orchestral music that I find the need for more extension. Our current sitting room is quite small and I may as well wait until we move before getting a pair of mammoths.

My Klipsch Heresy are great fun but they are -3db at 58hz. 

In an ideal world I'd get a pair of Cornwalls - I just about have the room for them - but they are now silly money (£6.5k new) and this has inspired 2nd hand prices to become just as daft (relatively).

Are two subs necessarily better than one? I thought that bass was mono below a certain frequency?

Edited by savvypaul
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1 hour ago, savvypaul said:

My Klipsch Heresy are great fun but they are -3db at 58hz. 

In an ideal world I'd get a pair of Cornwalls - I just about have the room for them - but they are now silly money (£6.5k new) and this has inspired 2nd hand prices to become just as daft (relatively).

Are two subs necessarily better than one? I thought that bass was mono below a certain frequency?

I think that the main advantage is that with two or more subs you get a flatter response in the low- and sub-bass (I put a link to a test in one of my first replies). It will also raise the SPL ceiling, although we are more tolerant of distortion at such low frequencies and as you say our localisation ability in this range is virtually non-existent (apparently the threshold is below 80Hz, here's an online test).

If I'm not mistaken the mk 1 to 3 versions of the Heresy of were sealed cabinet designs so you would probably get away without high-passing them.

Edited by tuga
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1 hour ago, tuga said:

If I'm not mistaken the mk 1 to 3 versions of the Heresy of were sealed cabinet designs so you would probably get away without high-passing them.

Yes, sealed box. They are reputed to be easy to do well with subs - at least that's the impression I get from owners on the Klipsch forum.

I've read a few recommendations for this DSP unit that sits between the preamplifier outputs and the sub: http://www.bkelec.com/anti-modes/AM8033SII.htm

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31 minutes ago, savvypaul said:

Yes, sealed box. They are reputed to be easy to do well with subs - at least that's the impression I get from owners on the Klipsch forum.

I've read a few recommendations for this DSP unit that sits between the preamplifier outputs and the sub: http://www.bkelec.com/anti-modes/AM8033SII.htm

I remember when they first came out. Probably still worth getting for it's ease of use but all in all a rather crude tool for the job.

Their Anti-Mode 2.0 Dual Core or a miniDSP DDRC-24 would be better options. Maybe @MartinC can chime in...

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