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been reading a bunch here and learned a lot...enough to have a plan even! however, i would appreciate a reality check...and maybe even a slap in the head (
) if i've missed/misinterpreted anything.


here's the relevant equipment / details:
  • yamaha rx-v2600 (output labeled as 'subwoofer', menu adjustments refer to 'LFE' and 'subwoofer' separately)
  • def tech bp2006tl mains (8" x 250w integrated 'sub', 4.75" mids, def tech says flat response to 33hz, have both speaker level and LFE inputs...internal x-over sums the lows from both inputs)
  • def tech clr2300 center (same driver arrangement, no LFE in)

usage is almost entirely theatre (i have a nice 2-channel for serious music). room is ~3800cuft (30' x 16' x 8'), and in short i believe that the room is too big and/or the subs are undersized. with the sub levels raised to the point of adequate SPL, it's flat-out muddy (overdriven?). more significantly, the truly low end rumble isn't there (and never has been, even w/ 3x 8" / 250w 'subs'). i want what we all want...tight, accurate, punch!


so the obvious answer (at least to me) would appear to be a standalone sub. no, i'm not sure which one yet. leading contenders are the SVS PB12-NSD and the hsu VTF3.3. in any case, my dilemma is how to best integrate a true sub with the def tech pseudo-subs.


current receiver settings (pre-standalone sub)
  • all sources output digital bitstream (via HDMI and S/PDIF coax) to receiver, which handles all decoding
  • 'large' fronts & center
  • 'bass out' to subwoofer (other choices are 'both' and 'front')
  • 80hz 'bass x-over' (choices 40/60/80/90/100/110/120/160/200hz)
  • normal sub phase
  • 0db 'LFE level' (range is -20db - 0db)
  • there is also a 'subwoofer speaker level' adjustment (-10db - +10db) that was set using avia and an SPL meter


there are also sub level controls on the speakers themselves...set to def techs recommendations (1 o'clock mains, 2 o'clock center...whatever that means), so as to provide a constant there, with all tuning done at the receiver. speakers are currently connected using both speaker-level and LFE inputs, making the receiver x-over setting largely irrelevant i guess.


so, gory detail behind us...


my plan is to move the receiver subwoofer output away from the fronts and connect it only to the true sub, using the receiver x-over to cut out the lows sent to the front stage. my thinking is that this will let the 8" 'subs' up there function more as mid-bass. i'm not sure where the x-over is between the (small) midrange drivers and the 8" 'subs', and i want to make sure the 8" have something to do! i envision the true sub located near field, with no corner loading.


other than the connection change, the only other change i see is in the receiver x-over frequency. def tech recommends a 'fairly low' x-over setting...40-50hz. my choices are 40 or 60. i realize there are slopes, but where would that 40-60hz info be better realized...at the 12" big hitter or the 8"? again, def tech says they're flat to 33hz, and i believe the x-over to the mids is ~80hz (which seems awfully low for the 12cm mid drivers).


obviously, the entire setup will be recalibrated w/avia once the changes are in place.


final question...how about the LFE level setting? i see in the sticky that this channel is designed to be boosted by 10db and should be handled correctly by the receiver's decoder. so that means set at 0db on my system...calibrate there and leave it there?


thanks for any/all input, and phew...sorry to ramble!
 

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I'll answer the last question first. You need to set the LFE level to its default setting. Per the "sticky" it should be set to the higher of the settings available to you. So, yes, in your case "0dB" is correct.



Properly implementing speakers like yours with built-in "subs" presents many people, in their minds, with a dilemma. I put "subs" in quotes because, as you seem to already know, they are not true subs. You seem to have a very good grasp of your options and the implications. I think you are definitely on the right track with your plan to run your speakers as SMALL but with a lower crossover so as to take advantage of their "subs". Many people are stubborn about this and insist on running these speakers as LARGE when using an outboard sub. And some even insist upon connecting their "sub" sections (at least for the fronts) to their subwoofer output when using an outboard sub, sending the LFE channel to their speakers' "subs" as well as their outboard sub. YOU, on the other hand DO seem to be thinking very clearly about this. Great.


So, an issue you have, as you well know, is deciding upon which crossover setting(s) to use. Does your receiver offer individual crossover settings for each speaker set? If not, one thing you have to consider is not setting the crossover setting too low for your surround speakers (which I didn't see mentioned in your post). Another thing to consider, as you point out, is which driver, the subs or the speakers' "sub", can reproduce the bass best in that 40-60Hz range. One thing to consider when considering this question, also, is that the higher the better in terms of the benefit gained by the SMALL speaker setting at the amplifier level. ALthough I do not know that the 20Hz difference between 40 and 60Hz is going to make that much difference in this respect. And I guess another thing to consider, as you point out, is where the speakers' "subs" are crossed in with their upper sections. So, you may want to try to figure this out. I suspect it may be 80Hz but you could email DefTech about this if it is not clear from the literature you have or their website.


Another thing to consider is whether your receiver truncates the LFE signal at the crossover setting. I do not know the age of your receiver, but many older receivers do this. If your receiver does this, then the lower the xover setting the more the LFE channel is truncated.


And, if your receiver has pre-outs, I think you also have the option to use those to connect the speakers' "sub" sections. But I think it is probably best to simply connect the speakers with speaker-level connections, only, and treat them as one integral unit.


So, I do not know what to tell you. There is no "correct" answer. You should experiment. I suspect the speakers' "subs" will perform better than the sub itself from 40Hz up, but that is only a hunch.




Another very important issue you face is deciding how and where to set the output level of the speakers' adjustable "sub" sections. I think there are several ways to do this. One would involve adjusting the speakers' "subs" levels, initially, with them running as LARGE. If you have an SPL meter (or better yet, a better method for measuring FR) you could adjust each one individually, when running as LARGE, for as flat a response as possible (if a flat FR is what you desire). Then, when you set them to SMALL and add in a sub, you could further adjust them, individually, while simultaneously adjusting the sub for as flat an overall response as possible. Or, if you are going to use an SPL meter (or better method), you could just go ahead and set them to SMALL and dive in and start shooting for a flat FR (if a flat FR is what you desire).


Of course, if you do not have the means or do not want to do a bunch of measurements, you can just set everything to taste. So, you can adjust the speakers to taste, initially, while set as LARGE. Using 2-channel music would probably be the best way to do this for the fronts. Doing this for the center may be a bit more difficult, although I'm sure you could figure something out. Then you could make the decision, once they're adjusted to taste when running as LARGE, to not change their levels when you switch them to SMALL and add in a sub. This would be similar to the situation one faces when using a standard speaker that doesn't offer the adjustability you have. On the other hand, if you are going to adjust the sound to taste, you COULD just use the speakers' adjustable "sub" sections inconjunction with the subs adjustable volume to tune your whole setup.


Either way you do it, there are a lot of different things that can be adjusted individually but NOT really independently. You have the speakers' "subs" volumes, the sub's own volume, and the individual speaker level trims that you will use to calibrate the channels' levels. Not really an easy task when you consider that each adjustable setting available to you will have an implication for all the other adjustable settings. So you can need to have some sort of plan or methodology, whether it is really sound or not, OR you could just dive in and do things sort of randomly.


Now, if your receiver offers some sort of auto-cal/EQ capability, such as YPAO, you will probably want to use it, although there are still going to be some steps you need to take to adjust the speakers' "subs" output prior to running it. YPAO only has limited EQing capabilities and you also want to apply as little EQ as possible. So, it would probably be in your best interest to give YPAO a sort of head-start by adjusting things to be as flat as possibly manually prior to running YPAO.



So, yes, your speakers DO complicate things a bit. If it were me, I might be tempted to adjust the speakers' "subs" to a flat individual FR, or to taste, when running as LARGE, and then resolve to not touch their "subs'" levels after that. Just treat them as a normal speaker. On the other hand, if you can get a good handle on it, they can provide you with quite a bit of adjustability and attenuation. "Getting a handle on it" being the operative phrase, there.
 
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