I built two very large main speakers and find the system performs better when using a powered sub. Originally, i thought large mains would eliminate the need for a sub. Of course i am keeping the sub and enjoying the warmth and punch it adds. Is anyone else also using a sub with large main speakers? Now i am wondering about building an even larger sub to get even more performance.
Godzilla
Godzilla
Godzilla said:
I use to run four subs even though the mains were tuned to 40 Hz since you want the mains BW to overlap the sub's somewhat and multiples to both increase acoustic efficiency down low and help somewhat with room modes, so recommend you do likewise rather than going for one big one.
GM
Makes sense to me, especially if you're crossing to the sub higher, relieving the mains of some of their LF duties with the benefit of lower distortion.Godzilla said:
With the new system I'm building the mains will be set to 40Hz via a Linkwitz xform for low level/late night music, and 60Hz and subs below that if I want to crank it. Perhaps I'll find a preference for the subs on always. Time will tell. When I added the LABhorns under my KHorns I thought I'd only use them for movies, but it turned out to be everything.
Godzilla said:
Build some more rather than one large one. It'll make it easier to spread out room modes. Look fro Toole's papers on the Harman site regarding subs and loudspeakers in rooms.Earl Geddes mentioned earlier today that he may post a how-to setup piece on this subject in the near future.Godzilla said:
Godzilla said:
Yes, all typical rooms have standing waves and there's no place in a room where a ~flat response can be had with just one sub, so a 'stereo' pair is considered the absolute minimum regardless of room size. Really, due to room modes extending up into our acute hearing BW, smaller rooms typically need four or more subs spread around as does room ratios that fall too far outside a golden or acoustic one: http://www.harman.com/wp/pdf/multsubs.pdf
Since down low the WLs are long enough for fairly widely spaced subs to sum, they can be smaller with the trade-off of course being more expensive than a single large one due to the extra drivers (and plate amps in some apps).
GM
So two powered subs - one each next to or near my BIBs - would sound better than one sub all by itself. Or would one of the subs need to be in another part of the room for optimal performance?
http://www.zillaspeak.com/systems.asp
I have an old ACI sv12 sub. I understand i can buy another one from Meniscus Audio. Maybe two of these would really round out the already amazing sound i am getting from my stand alone BIBs. Might as well get the most performance i can while i am still alive and well! I want to treat myself really good since my operation. Do the subs have to be the same? Or can they be different. Say and 8 inch sub in a small box and a 12 inch sub in a big box. Or am i thinking about this too hard and being wasteful?
Godzilla
http://www.zillaspeak.com/systems.asp
I have an old ACI sv12 sub. I understand i can buy another one from Meniscus Audio. Maybe two of these would really round out the already amazing sound i am getting from my stand alone BIBs. Might as well get the most performance i can while i am still alive and well! I want to treat myself really good since my operation. Do the subs have to be the same? Or can they be different. Say and 8 inch sub in a small box and a 12 inch sub in a big box. Or am i thinking about this too hard and being wasteful?
Godzilla
Actually, per the Harmon paper, Dr. Geddes in another thread and numerous other papers, DIYers, subs near/next to the mains is almost never the best compromise positions and why wide BW mains and separate sub systems are preferred.
No, they don't and often need to be different since they're being used as much for acoustic room correction as for bass extension, a point I've periodically made. Still, unless you map the room to determine what's needed it's best to err on the conservative side and at least use the same size and adjust the tuning/level as required.
GM
No, they don't and often need to be different since they're being used as much for acoustic room correction as for bass extension, a point I've periodically made. Still, unless you map the room to determine what's needed it's best to err on the conservative side and at least use the same size and adjust the tuning/level as required.
GM
Re: Re: Using subwoofer with large main speakers
I did post that, just don't remember where.
Usuing multiple subs spread arround the room is the single most effective way to get good bass that I have found in years of research. I don't care what kind, what tuning, what bandwidth, what size, what anything as long as there are at least three and they are 1) one in a corner (if its a monopole) 2) a second as far away from the first as possible (not in a corner) 3) the third can go almost anywhere as long as it is far from the others. I usually do the third along a side wall. Then set them up per the procedure I stated (if someone can find it).
There are things that can improve on the situation above, like well damping the room with flimsy well damped walls and ceiling. And putting one subs above the rooms centerline. Stagering the subs tuning for small bandwidth and high efficiency. But the above is just about a minimum IMO.
And yes, keep the subs some distance from the mains. DOn't have to be extreme about this, but closer is certainly not better.
Brett said:
I did post that, just don't remember where.
GM said:
Usuing multiple subs spread arround the room is the single most effective way to get good bass that I have found in years of research. I don't care what kind, what tuning, what bandwidth, what size, what anything as long as there are at least three and they are 1) one in a corner (if its a monopole) 2) a second as far away from the first as possible (not in a corner) 3) the third can go almost anywhere as long as it is far from the others. I usually do the third along a side wall. Then set them up per the procedure I stated (if someone can find it).
There are things that can improve on the situation above, like well damping the room with flimsy well damped walls and ceiling. And putting one subs above the rooms centerline. Stagering the subs tuning for small bandwidth and high efficiency. But the above is just about a minimum IMO.
And yes, keep the subs some distance from the mains. DOn't have to be extreme about this, but closer is certainly not better.
PeteMcK said:
Some years back I would have been in total agreement with you. In hindsight I don't know why it took me so long to see. Ever since I tried this approach I have never done anything else and my rooms always have great bass. Its the answer, of that I have no doubt.
Just buy powered subs. There cheap and the amps usually have the necessary controls. The only problems that I have had has been with hum. They can often be on different power circuits when they are spread arround the room and I am forced to use the speaker feeds to avoid the hum.
Using a good sub with large main speakers sounds great.
The sub fills in the low bass that the mains won't play as well. Your mains play the full range, and the sub helps with the drums and bass notes.
IMO you can get less distortion by turning the bass down in the mains and letting the sub play most of the bass.
The sub fills in the low bass that the mains won't play as well. Your mains play the full range, and the sub helps with the drums and bass notes.
IMO you can get less distortion by turning the bass down in the mains and letting the sub play most of the bass.
bjorno, if i am reading your sims correctly you modeled a box that is 50 inches tall (100 L folded in half), 15 inches wide (where the driver is placed) and 20.75 inches deep. There are two ports 2 x 4 inches at the bottom of the box. Do the ports simply go thru the inner baffle?
Thanks,
Godzilla
Thanks,
Godzilla
Yes, they do!
Also a late reply to:
IMO, that’s a good idea. Arguments:
http://www.icad.org/websiteV2.0/Conferences/ICAD2002/proceedings/71_Martens.pdf
One or two subs that goes below lowest modal frequency is IMO only necessary for the case of HT use but if in total of two or more, it’s easier to get a smoother FR at the listening area that also better suits music listening.
In addition to one or two main subs, one or two smaller bass speakers can be placed laterally in order to secure an externalised overall bass que i.e. avoiding ‘sound inside head sensations’.
Laterally placed bass speakers normally don’t need LF extension below 40Hz (but signal td is often needed to balance the speaker distances for optimum result).
The additional bass speakers, when operating within room discrete modal range should also support an improved stage width appearance (constant width) if a suitable BW: s and SPL: s are chosen. See picture 1(1) that applies for symmetrical set-ups.
Extending the # of subs where diminishing returns is at a # > 4 in total, in a room symmetric set-up of the main speakers improves the FR smoothness of bass octaves at the listening area whence one sub is enough for the case of HT LFE when operating below lowest room modal frequency.
The additional bass speakers, when operating within room discrete modal range should also support an improved stage width appearance (constant width) if a suitable BW: s and SPL: s are chosen.
If placed at closer listening distance than the mains, signal delay, i.e. excess phase must be removed and phase should be adjusted (necessary for a tight fused lower octave image minimum spread when acoustically crossing over to the mains) and can be placed asymmetrically for best result.
If the subs are (only) placed at the rear they must be of good quality as rub and buzz localisation artefacts are easily heard segregated when originating from the outside of the mains including within cone of confusion where the limit for frontal phantom spread or image position/stage width ends.
b
1(2)
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