"The Ultimate Subwoofers" Part Deux

[sergiup]

Part Deux please?

 

[IronGiant]

Since you asked so nicely, enjoy

carrying on from here: http://www.avforums.com/forums/subwoofers-tactile-transducers/1744516-ultimate-subwoofers.html

 

[Ashmanuk]

I haven't got up to reference yet (shut it Ashman! ;-)) but will be getting ridiculous over the next few days.

LOL I haven't said anything YET!!!!!!!!

 

[KelvinS1965]

Just saw the comment about reference being a bit of a push for a single 15". Since that's my aim (although I do tend to listen 5-10db down usually I want a bit of headroom) I don't want to find I'm still blowing up subs.

Just to clarify, what is reference for a sub anyway? I thought 105dB average plus 10dB peaks. Of course it also depends on distance too I suppose but I'm about 3.5 metres from mine.

 

[Member 639844]

Just saw the comment about reference being a bit of a push for a single 15". Since that's my aim (although I do tend to listen 5-10db down usually I want a bit of headroom) I don't want to find I'm still blowing up subs.

Just to clarify, what is reference for a sub anyway? I thought 105dB average plus 10dB peaks. Of course it also depends on distance too I suppose but I'm about 3.5 metres from mine.

Reference in terms of THX etc, is 105db clean to 20hz at the listening position, with the 20hz stipulation being because lower frequencies are harder, so hitting this target will take care of the entire range above it. True reference level for the LFE channel is 2-120hz, average spl 85db, and max peak potential of upto 115db (with potential for an additional 3db with redirected bass also joining the party). The chances of a 3 hz 118db peak being in the sound track are pretty slim, but thats the potential built into the channel for sound mixers to play with.

Our single 15 will be capable of running at reference level without you killing it, but there will be limits to what its actual output will be. 105db at 20hz is realistic, 115db at 10hz simply isnt, and that goes for any single sealed 15 inch subwoofer, not just ours

Given the levels your talking about, I do think a pair of 15's is what you should be looking at for peace of mind, and of course the 18 is looming, with the driver due to land this week.

 

[KelvinS1965]

Thanks for the detailed explanation there Dan. It's not surprising that the Monolith died even at -10db down (especially since it's a dB or two 'hot' as well). Obviously not every film will achieve this; we watched 'Once upon a time in America' a couple of nights ago with the damaged Mono and it didn't cause it any problems for example. Not your typical blockbuster action movie in LFE terms though.

I think I'd be OK with 105db at 20Hz, with anything above that limited (and the ultra low frequencies rolled off as required). As you say I'd not get anymore from another make of the same size either. I just don't think 2 x 15" singles is realistic in my current room/current budget (though should be possible in the dedicated room I'm hoping for in a couple of years time).

 

[Member 639844]

I think a single 15 at -10 will be fine. At -5 you might find occasions where some very heavy scenes could start to see it being pushed hard, and reference level will no doubt have moments that can really make a single 15 work hard. As I said before though, you dont need to worry about hurting the subwoofer like you have experienced with the monolith, the system will never suddenly unload the driver (as happens below port tune), and everything about its design is intended to help protect the system from damage when pushed hard. You should find it nigh on impossible to force the driver to hits its absolute limits, and the amps have the usual thermal and soft clip sensors in them so protect them from damage. I'd be surprised if you managed to kill one of our subs at -10 to -5, and while its a possibility to kill it at reference, I cant imagine a scenario where you wouldnt notice the sub struggling for long enough to do the driver any permanent damage.

In short, I think your Monolith experience has made you very aware of the potential a sound track has to push any system hard, but has probably also made you a little over cautious in relation to how tough I think our subs actually are.

 

[mattkhan]

It's not surprising that the Monolith died even at -10db down (especially since it's a dB or two 'hot' as well).

have you killed 2 monoliths at -10dB? if so, do you have (REW or similar) measurements for how they are responding in room? I suppose I am really asking there are you actually driving them at way past -10dB. I ask because I used to have a monolith and it was often (albeit not normally) driven in the -5 to -10dB range & hence am curious as to what you're doing to kill it repeatedly (fwiw my current sub can sound strained at those levels so it's not surprising per se, just seems a bit unlucky alf!)

Cheers
Matt

 

[KelvinS1965]

I think you're right Dan. It's been maybe 4 years since the original driver went and I was just starting to think it was set in such a way that I was safe up to my usual listening levels. One rogue disc proved me wrong (shame it wasn't even a decent film either IMHO), but it shows that it's a fairly infrequent occurrence considering how many films I've watched in that period. Maybe £130 every 4 years isn't bad, but of course I'm after an improvement. Reading the responses from those who have heard the 15" seems that I shouldn't be disappointed on that score.

As you've said previously, it's easy enough to plan for adding a second sub later by selecting the bigger amp to start with.

I think it's good timing that this thread has hit it's 'part deux' just as we're starting to get feedback from out in the field...waiting to hear more from Paul.

 

[KelvinS1965]

Yes Matt: The first driver was killed at -15db (War of the Worlds) but that was partly due to Audyssey on an old amp that applied a 13dB boost at 20Hz or so. This one was -10dB on The Amazing Spiderman (though running a dB or two hot, so consider it -8dB for the sake of argument). As my OH said afterwards, it wasn't even that loud though I've noticed since I've now got the full set of PMC speakers that I'm tending to listen louder as they just don't sound strained at all.

I run an Antimode 8033 and I've measured manually using my SPL meter and an excel spreadsheet that I got from here a few years back. Keep meaning to try REW but got sidetracked learning display calibration and Chromapure in particular. Now my displays are 'perfect' I'm turning back to the sound side...

 

[scottthehat]

Totally agree with Dan my 15 with a big bass hitter like cloverfield will do -5 after that its pushing it.
But other low bass films it will do reference.
just knowing the film and what the bass is like. But like Dan said the more subs the better and easier each has to work which means louder.

 

[PHTheLoverman]

Referring to an earlier question...
My Audyssey had been run recently and changed the frequency settings to 40hz(!). This changed the sound of the MKs and they were then set to the 80hz that they should have been at. With the 15" I believe they are now at 120hz.

 

[Member 639844]

As my OH said afterwards, it wasn't even that loud though I've noticed since I've now got the full set of PMC speakers that I'm tending to listen louder as they just don't sound strained at all.

The thing you have to remember is that 95db at 10-20hz doesnt sound anything like as loud to the ear as 95db at say 80hz. Add to this that the driver has to work a lot harder just to maintain the spl, and its quite clear as to why low frequencies can kill a driver pretty quickly even though they dont seem that loud. At -10, you still have the potential to put upto 105db through the LFE channel (and therefore your subwoofer) at any frequency within the LFE range.

To put a little perspective on it, the Monolith is capable of about 98db max output at 20hz.

 

[mattkhan]

Keep meaning to try REW but got sidetracked learning display calibration and Chromapure in particular. Now my displays are 'perfect' I'm turning back to the sound side...

fair enough, you clearly do just need all of those 18"

tbf REW is pretty straightforward to use albeit interpreting the data can be (is) an endless voyage of discovery. The cost of entry is relatively low now with USB mics & HDMI connectivity (driving 1-2 channels at a time over the same connection) supported via ASIO. I just ordered a calibrated mic, possibly (almost certainly?) overkill but my RS meter has recently showed some oddities so figured now is a good time to upgrade measurement kit.

Cheers
Matt

 

[MemX]

I need to REW my room but haven't got a laptop, so need a volunteer who is happy to be paid in Pizza and Beer lol

 

[ManGina]

Been reading this thread avidly since upgrade fever has me firmly in its grasp.
Couple of questions if I may. From the pics a few pages back I noticed just the 2 connections? My current sub (canton) is connected by a plumbed in mark grant sub cable. Does this range need two cables? What connects the external amp to my av amp? What are the dimensions of the 18" cabinet and how easy is it to get someone who knows what they're doing to set it up / calibrate it for me as clearly I don't have a clue ! Thanks in advance

 

[Darkmatter21]

Just an extra side note about reference level, it is 115 dB in the LFE channel, but if you combine the redirected bass if you crossover your other speakers to your sub you can be asking it to go as high as 126 dB which is a massive ask of any single sub.

In order to get near reference out of my pair of BK XLS200's I corner load them for about 6-9 extra dB headroom and obviously as a pair they get an extra 6dB as they sit on top of each other. But there is no chance they can reach reference down to 20 or even 25hz, I think according to the CEA2010 figures they can hit reference as a pair at 31hz and above.

 

[kbfern]

Hi Ya Paul

Are we getting further details of last nights listening session today pretty please.

 

[scottthehat]

Just an extra side note about reference level, it is 115 dB in the LFE channel, but if you combine the redirected bass if you crossover your other speakers to your sub you can be asking it to go as high as 126 dB which is a massive ask of any single sub.

In order to get near reference out of my pair of BK XLS200's I corner load them for about 6-9 extra dB headroom and obviously as a pair they get an extra 6dB as they sit on top of each other. But there is no chance they can reach reference down to 20 or even 25hz, I think according to the CEA2010 figures they can hit reference as a pair at 31hz and above.

Surely if you have a sub in use then your using crossovers which means redirected bass so is there any more info on this.

 

[Ashmanuk]

Referring to an earlier question...
My Audyssey had been run recently and changed the frequency settings to 40hz(!). This changed the sound of the MKs and they were then set to the 80hz that they should have been at. With the 15" I believe they are now at 120hz.

My XT32 always shows my fronts as 40Hz, I run mine at 80Hz for a while but Slingo did advise to try 100Hz and above so now I'm on 100Hz but my Fi drivers don't like it above 100Hz so I'm very surprised your on 120Hz.
When playing music with subs at 120Hz my Fi drivers start to sound very honky more bloated less defined.

I'm sure Dan said the 15"'s are using Fi drivers ?

 

[Ashmanuk]

Been reading this thread avidly since upgrade fever has me firmly in its grasp.
Couple of questions if I may. From the pics a few pages back I noticed just the 2 connections? My current sub (canton) is connected by a plumbed in mark grant sub cable. Does this range need two cables? What connects the external amp to my av amp? What are the dimensions of the 18" cabinet and how easy is it to get someone who knows what they're doing to set it up / calibrate it for me as clearly I don't have a clue ! Thanks in advance

The ultra subs company are a little different as in the sub cabinet is passive i.e a wooden box and sub driver then you add an amp of your choice which is an external amp, there using the inuke range which are very good value for the money.
So you would connect your Mark Grant RCA phono cable to the inuke amp as normal then speaker cable from the inuke to your subs speaker terminal. (Which is the two connections you see)
Hope this helps.

EDIT: sorry you would need to add one of these to your Mark Grant RCA cables, http://www.amazon.co.uk/Adaptor-XLR-plug-RCA-socket/dp/B0012IPSEW

 

[Darkmatter21]

Surely if you have a sub in use then your using crossovers which means redirected bass so is there any more info on this.

I decided against using redirected bass, so i set all speakers to full range. So the sub is only dealing with the LFE content. This is a personal preferance, mainly due to the ported 8 inch drivers of the RX2 outputting a similar ammount of depth to the 10inch sealed drivers of the XLS200, i didn't feel there was much need to crossover to get 5hz or so extra depth. There is obviously some downsides to this as it means the Onkyo is being driven very hard but i find it sounds better when you approach reference level than if i re direct. My assumption was that the subs are struggling and starting to sound muddled to me. If i had a beefier sub i would reconsider using redirected bass as it would give me much better depth than the current solution.

There are endless articles about this sort of stuff, is there any information you would like in particular?

Audioholics Subwoofer Room Size Rating Protocol

This is a good article, if you type in CEA 2010 subwoofer figures or the such like into google you can find them out for a given sub and see if it will likely reach the SPL you desire.

http://www.hometheatershack.com/for...hived/5748-cea-2010-standard-compilation.html

 

[Darkmatter21]

My XT32 always shows my fronts as 40Hz, I run mine at 80Hz for a while but Slingo did advise to try 100Hz and above so now I'm on 100Hz but my Fi drivers don't like it above 100Hz so I'm very surprised your on 120Hz.
When playing music with subs at 120Hz my Fi drivers start to sound very honky more bloated less defined.

I'm sure Dan said the 15"'s are using Fi drivers ?

I can imagine with a crossover at 120hz that it would sound a bit funny. If the slopes are -12/octave then wouldn't that mean it would only be -12 down at 240hz etc which is pretty high frequency for a 15 inch subwoofer to be playing at! I experimented with crossovers of up to 200hz and found that 80hz or lower worked best for me but maybe if i had -24dB/octave filters it would work better?

 

[mattkhan]

It's interesting that people (inc me whenever I've tried more than 110 or so) generally find a high crossover a bad thing yet these subs are configured at gecko with a 150Hz XO and sound great.

 

[scottthehat]

My acoustic elegance drivers sound better with a 150Hz crossover on front and my speakers have 2 8 bass drivers each and an 8inch mid. To me the sub sound better clearer and has more depth. And more in your face.