Subwoofers, tell me all about them ..

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Subwoofers, tell me all about them ..

Postby AndyU » Mon Oct 21, 2019 1:58 pm

OK, I’m kinda thinking about thinking about getting a sub-woofer, perhaps more than one, but I know nothing about them. I currently have a pair of ATC SCM50ASLTs with anniversary amp packs, and I’m using them well away from walls in a large room. Sometimes, especially after going to concerts, I think I could do with some more heft at the bottom end. So what kind of sub(s) should I be looking at? Are the ATC ones the way to go? If so, how do you connect them - I have a DAC pre with just XLR outs so do you use a splitter cable? Or some magic box? The ATC subs don’t seem to have pass through. Are there other alternatives? I should say that my interests are classical music, so I’m not interested in bass for its own sake, or thump-thump stuff, just musical bass for the sake of credibility. Any advice?

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Re: Subwoofers, tell me all about them ..

Postby darrenyeats » Mon Oct 21, 2019 8:41 pm

Hi Andy, I think you already know my opinion.

I used to own a sub (ATC C4) and ended up selling it. It's a decision I haven't regretted at all, not even a bit.

I addressed all my needs via speaker and listener positioning, and bass treatments. For me that was enough - but I have a small room. Otherwise, I'd have gone from my 50s to 100s or even 150s as necessary, rather than having a sub.

When it comes to positioning remember close side walls are bad. ATC recommend 1m distance, if you can't then treat side wall first reflection points (I do this). I agree that objects near the rear wall - equipment racks, furniture, TVs etc. may well disturb the sound. But _IF_ it's a plain wall, and long interconnects are used to keep it plain, there's no substantial issue with positioning 50s near the wall itself behind them, in fact in my opinion they like it. I believe people confuse problems with objects with problems with the wall.

You may well find that the room has a significant room mode. I addressed this with listener positioning, and bass treatments tuned precisely to the problem frequency (I avoid broad band stuff). You might find when moving the speakers nearer the wall behind them, you might need to move the listener position more into the room. That doesn't mean the two are exactly equivalent, they're not: it's really important the listeners have space behind them (at least 1m), this is more important than the speakers having space behind them (if aforementioned conditions are met).

I note Martin Colloms ended up placing 50SLs/50ASLs under review with a small-ish gap to the wall behind, and I agree. I suspect closer is better in many cases for a neutral balance.

An equilateral triangle between speakers and listener is a good aim, though this can flex a bit.

Others might prefer to use EQ/DSP. But I'm old school! I have my reasons which I can elaborate.
Last edited by darrenyeats on Tue Oct 22, 2019 7:56 pm, edited 2 times in total.

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Re: Subwoofers, tell me all about them ..

Postby Alastair » Tue Oct 22, 2019 9:54 am

Hi Andy

My sub choice was predominantly driven because I like film and wanted a sub with a lot of headroom to compliment my 100s. A good value C6 was found online from a shop outside the uk. The reality of having a young child in a shared room however means that film watching is now very rare!

That aside I took the view at the time that ATC would be a good choice given their general engineering and know how. If I was doing this again, I have to admit I would have liked to have tried some of the SVS models and possibly JL too. These seem to have a lot of praise, with many set up options.

Connections - not sure how to get around your current set up. No single ended outs?

Number of subs - I’ve not tried more than 1 but I’d certainly like to on the basis that it can potentially improve the evenness of the bass in the room? Not heard this in reality or tried but would certainly like to.

Regarding Darren’s very helpful and clear approach...I am quite the opposite having recently come around to fully embracing EQ. I am just very limited with where kit and I can be located in the room.

For stereo music and 5.1 film, Dirac has transformed the sound. I won’t say it’s perfect but it’s had a big impact on tidying up the sound which was frankly pretty poor due to the room set up. I am very limited to what I can do going down the more traditional and arguably, the right route regarding acoustic treatments and speaker/seat placement options.

For stereo music I have started to use the C6 as well. I listen to a lot of modern and classical music. Presently I find the addition of the C6 is quite subtle although I don’t feel I have optimised it yet, I purely need more time. Again I do use EQ but I have not fully exploited it (have the box but just using the crossover and gain options rather than the dsp/eq software). The house is also being decorated so really I can’t do much as the hi fi has now been moved to the dining room!

Takeaways in my view on the sub quest...

-Get a sub demo with a pair of active 50s like yours

-Try and borrow a sub once you’ve established your connection options for an extended loan I.e. more than a couple of days. I really feel you need some time to play around

In summary, the credibility you mention is something I am also interested in and I am pretty sure I can get some way with the C6 in my set up with some some dsp/eq help. Having said that, based on experience so far, the effects have been subtle so you’ve got to try and see if the whole exercise is worth it before sinking your hard earned money. Hence my suggestion of a good demo with someone who knows what they are doing, then home demo.

I can properly say a lot more on this so drop me a PM if you have more questions.

Alastair




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Sys 1: ATC Classic SCM100ASL, C1C, SCM11, C6, CDA2 MK2 / Krell Showcase 5 / Oppo 203 / Emotiva XMC-1
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Gym: Meridian DSP5000 96/24, DSP5000C 96/24, D6000, 568.2MM, 518
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Re: Subwoofers, tell me all about them ..

Postby tw99 » Tue Oct 22, 2019 12:46 pm

I'd be surprised if going for subs was the best answer to getting more bass, if you're listening mainly to classical music. I have a C1 sub that I use with my SCM40s, and if you set it up as ATC recommend (crossover at 48Hz) then on most material, even rock/pop, it's doing practically nothing. The sub is most useful for watching films in my experience.

The way I adjust my system to my taste is by using room correction and boosting the response below 150hz or so to get an overall downward-sloping frequency response from bass to treble.
NACD3.5 | SBT / DSpeaker anti-mode 2.0 / SIA2-150 / SCM40 + C1

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Re: Subwoofers, tell me all about them ..

Postby paul_riordan » Wed Oct 23, 2019 8:12 am

I currently have 50As on the front channels of my 5.1 surround system with a C4 sub. When listening to 2 channel music I have not found any need to add additional bass. The sub works well for films and surround music. My speakers are about 1m from the rear wall, probably very slightly closer to the sidewalls and that might be why they seem to work for me. I guess you have a few options if you want to get a bit more bottom end from your system:

1. Upgrade to 100s (or bigger) should help get more bottom end due to the larger driver(s).

2. Add a subwoofer (or two) - Personally I would go down the ATC route mainly because the voicing of the speaker/amp will mean it should be easier to integrate. You could try using a pre-amp like the Emotiva which has sub outputs - https://emotiva.com/collections/pre-amps/products/xsp-1 - I must admit I don;' like using cable splitters.

3. Room treatment / placement changes is also a good option and probably not too expensive

Not sure if I have helped or not but at least you do have lots of options...

Cheers

Paul
Source: Auralic Aries + Mytek Brooklyn DAC+
Video source: PC
Pre-amp: Mark Levinson ML380s
Cinema Processor: Anthem D2v
Speakers: ATC SCM50ASL (Front and Centre), ATC C4 (Sub), ATC SCM20A-2 (Rear)
Screen: Pioneer KRP-600A

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Re: Subwoofers, tell me all about them ..

Postby SA Audiophile » Wed Oct 23, 2019 3:57 pm

I have a pair of 50A's and have been trying unsuccessfully for the last few years to integrate a sub into my stereo system. I've tried a Rel 528SE and currently have a Sunfire True Sub. The Sunfire actually integrates better than the Rel, but the problem remains - regardless of where I place the sub, or what cut-off frequency I set it at, there's almost always a frequency band where the ATC's and the sub overlap, causing an uneven bass response. This problem is especially evident on the highly compressed modern day recordings where the bass is already over emphasised. Essentially one recording would sound good and the next less so and I end up tweaking more than I listen! Given my experience I would think the only way in which one would get a sub to integrate with the ATC's is to somehow limit the frequency range of the ATC's to say 50hz and then set the sub to 50hz, but to do this one needs something like an AV processor. Good luck!
Source: DCS P8i
Speakers: ATC SCM 50A on Mana Acoustics Stands
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Re: Subwoofers, tell me all about them ..

Postby Alastair » Wed Oct 23, 2019 4:07 pm

SA Audiophile wrote:I have a pair of 50A's and have been trying unsuccessfully for the last few years to integrate a sub into my stereo system. I've tried a Rel 528SE and currently have a Sunfire True Sub. The Sunfire actually integrates better than the Rel, but the problem remains - regardless of where I place the sub, or what cut-off frequency I set it at, there's almost always a frequency band where the ATC's and the sub overlap, causing an uneven bass response. This problem is especially evident on the highly compressed modern day recordings where the bass is already over emphasised. Essentially one recording would sound good and the next less so and I end up tweaking more than I listen! Given my experience I would think the only way in which one would get a sub to integrate with the ATC's is to somehow limit the frequency range of the ATC's to say 50hz and then set the sub to 50hz, but to do this one needs something like an AV processor. Good luck!


I’ve spent some time doing the latter I.e. use a processor with bass management to essentially create a 2.1 system. It’s not bad but just does not quite sound right to me, I tried multiple crossover settings from 30-45Hz and played around with the gain. I was though forever thinking I could hear the sub and getting distracted by that. It might have worked better if I could shift the sub around the room and speakers but that’s just not an option for me. Plus it seemed a shame to rob the 100s of running full range, it’s not like they struggle.

Out of interest did you ever try the running the sub a out of phase?
Sys 1: ATC Classic SCM100ASL, C1C, SCM11, C6, CDA2 MK2 / Krell Showcase 5 / Oppo 203 / Emotiva XMC-1
Sys 2: Quad Pro-63, Elite QSP, Pre & CDX
Gym: Meridian DSP5000 96/24, DSP5000C 96/24, D6000, 568.2MM, 518
Roon, Tidal, Dirac

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Re: Subwoofers, tell me all about them ..

Postby SA Audiophile » Wed Oct 23, 2019 4:14 pm

Interesting! I can't think that you'd want to add a sub to the 100's :-) !

Yes, I have played around with the phase of the sub quite a bit. I think the issue is that the 50A's extend a lot deeper than what the spec sheet says - even with the sub set to its min of 30hz there's sometimes still an overlap. When the sub is set out of phase the effect described above is the inverse, so it takes away some of the bass in the area where they overlap, again leading to uneven bass response.
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Re: Subwoofers, tell me all about them ..

Postby MattSPL » Sun Oct 27, 2019 3:34 pm

Hi Andy,

I used a single JL Audio f112 with ATC scm50asl’s. This was a very nice combination. The new version 2 JL Audio subs will be even better as they have multiple EQ bands as opposed to the single band EQ in the version 1 subs that only tamed the worst peak in the subs frequency response.
Correct positioning is vital with a single sub, otherwise the bass balance will favour left or right, giving an unbalanced sound. 2 subs are much better, giving an even sense of pressure in the room. I imagine 4 would be optimal.

Buying a usb microphone and downloading REW is a must to properly integrate a sub(s). Measuring the impulse response of the speakers and sub to make sure the sound arrives at the listener at the same time is very important, otherwise you get a smearing of the bass, which is why I think a lot of people don’t get on with subs.

I currently use 2 DIY 18 inch subs and dsp. I apply a HPF at 62.5hz to my speakers to remove the deep bass and set the LPF to my subs at 62.5hz. The subs are run as a left and right, so it’s like a 3 way speaker system that extends down to 5hz. The bass is seamless and not overbearing. On some recordings, usually older or poorer quality ones, there isn’t that much bass as is evident when listening to ATC speakers, yet when there is bass in the recording it is deep and room filling.
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