[randog]

I am very curious about using subwoofer cabinets as stands for bookshelf/monitor speakers and whether vibration is an issue.

I don't have any experience in this but somewhere deep inside something tells me that the vibration caused by the low frequencies of the sub(s) can't be a Good Thing for the mains. Is this a valid concern? Full-range floor-standing speakers are built as a cohesive structure so I don't see that as a valid comparison.

I'd really be interested in hearing some thought-provoking banter on this.  

Randog

[Tyson]

If your subs are VERY rigid, and VERY heavy, and your main speakers are also VERY heavy and rigid, you could get by putting the mains on the subs - just put some sorbothane under the speakers so the vibrations that are there will be absorbed.

[U4EA]

I think you would be asking for trouble here.  I would build a shelf or false box to mount the speaker right above the sub if I had to do it this way.  

Subs should be placed for sound.  Sometimes this is not an option because of room configuration or WAF.  But maybe you should give this a try.  Placing for sound that is.  There are many tutorials on the web dealing with sub placement and tuning.

THis is a good one http://www.smr-home-theatre.org/Sub-woofer-Set-Up/

[Ravi]

Let me go against the grain here...I think it should be fine to use subs as stands for your speakers.  If the subs are well built, and you use some damping material inbetween the sub and the speaker, you'll have no problem.  I mean, a 3 way in separate chambers is virtually the same idea.  As long as the sub is not a Tumult, or some other super sub thats gonna rattle the speaker to the floor, you should be fine.  I would even say to fasten the speaker to the sub, to avoid vibrations from knocking the 1801s right off.

[Tonto Yoder]

Check out some of the Von Schweikert speakers that have mid/tweets in a seperate box sitting atop a woofer enclsure.
http://www.vonschweikert.com/vrline/VR-45M.HTM

[John Bauder]

ACI has a set up like this with powered subs.  http://www.audioc.com/speakers/JagLE/intro.htm

Maybe Mike would like to comment on the pros and cons.

[nathanm]

When I can afford one my plan is to get a 2nd sub and place the main speakers on top of them.  Personally I am not fond of the bass coming from one area of the room and the rest from another.  I think it will be cool with everything projecting from one general area. A sheet of rubber or something would prevent the smaller speaker from vibrating off, if one is lucky enough to play 'em that loud.  Also would make a protective barrier!  I already put a nice scratch in an otherwise flawless black gloss finish by a simple 3 inch slide of the main speaker across the top of the sub.  Foolish!

The other thing to consider is, the vibration will be in-time with the music so unless you are playing a different song on the mains from the subs it wouldn't be that big of a deal.

[ABEX]

Wilson does this by attaching the Mid And Tweeter boxes over selaed Sub units.

There are a few things to consider and it would be wise to see where the manf. says the sub units should be placed in a room.RELs might be able to do it,but they are expensive.

I would make a stand out of angle iron that fits along the edges of the subs and taper the angles so the spaekrs fit over the subs with the tweeters at ear level.

I have thought about doing that,but I just sold my sub yesterday and the speakers I have coming will go to 27Hz. so I really do not need a sub till I can get a REL with a XO point at 27Hz..
 
Happy building!

[randog]

Funny you mention that...
The purpose of this post is because I have an idea of a design to isolate the speakers from the subs while still using them as stands. I wanted to get a consensus as to whether it might be necessary. So far, the opinions seem pretty split.

Randog

[Tonto Yoder]

Don't know what you have in mind, but you might consider the high-tech looking Goldmund speakers that make the isolation of boxes quite obvious.