didn't PWK comment on the general effect of raising a floor standing speaker off the floor in a "Dope from Hope"? - can't find it - maybe I'm mistaken
I think I understand.
In the case of a massive/rigid floor, there would be no extraneous vibrations ..... but in the case of a suspended floor, i.e., joists suspended at each end, the floor structure should be isolated from the speaker enclosure to minimize extraneous vibrations.
Am I close?
Right, VLF, but the lower the fundamental, the wider its BW, hence the higher frequencies can be perceived if not outright audible.
with regards to "coupling" or "decoupling" to the floor structure, what is the range of "higher frequencies" you are referring to?
Potentially all the way up to the XO point roll-off, though by then very low amplitude, but in general 'we' (mostly women and assume children IME) might hear a bit of added 'color' up to 4 octaves away, or 2^4 x the fundamental.
How about some L-stands? Easy to make from wood/MDF, 30mm perhaps? Two of these connected however you see fit... From the front they have a slim profile, sides can be shaped easily too.
(This is just 30 sec. drawing to give example).
Any chance the speakers can be wider to go with taller? They respond well to A800 baffling, especially if raised on stands with bottom baffle to complete the false wall. board, though of course don't have to be cinema sized.
Ok, I'm just looking at the contact points in the picture, and considering how to maintain the same contact in an easy way. The visual aspect matters too 🙂.
Anyway, if I can ask of those how knows: how important is the contact/interface to the floor? Also, the properties of the floor would matter, no?
If I were you, I'd do some simple lests, have a listen 🙂. And maybe measure the result, if possible.
Dagfinn
Remember those "carpet spikes" some cabs have on the bottom? Those - I assume - are to keep the cabinet from slip-sliding around on the carpet surface. When the spike penetrates the carpet, any padding and sinks its tooth into the wood of the floor, it more or less locks the cabinet in place regarding any (micro) motion parallel to the floor surface.
Once a cabinet is big and heavy enough, it's not going to move that much. Dont know where the sweet spot is, regarding effectiveness of the spike solution. Dont know what to do that'd be equivalent, for a bare floor, a concrete floor etc. (I wouldnt want little depressions left in the wood of my floor, just so the speakers could sound a little better. Permanently carpeted, "who cares"?)
I'm sure someone makes a product for that.
Hm, yes it's hard to find info on decoupling/coupling of speakers and stands. This is useful @GM https://trueaudio.com/st_spcs1.htm. The more I read about bass, the more the room properties becomes important. A floot isn't just a floor. In my house I have a laminate on concrete in one room, and a laminate on a regular woodbeams/laminate divider floor. One is non-resonant, the other a massive baffle extension - very resonant. Walls and ceilings the same, very different. So predicting anything like bass response based on size/dimensions is futile, each room and position will be highly different. Looking at OP's floor, it could be anything underneath the surface. If it's a void, like some of mine, it'll have a big effect on bass propagation. But how important the coupling or de-coupling is, I don't know...
It isnt obvious? If it's a void, you want zero excitation, so no coupling, perhaps suspended speakers. If it's over a concrete slab, take advantage of that "immovable" mass by coupling to it strongly. The problem for a speaker builder, manufacturer is they want the product to sound good, but have no idea where in a dwelling it's going to be put. So they provide little hard feet or carpet spikes that you can screw into receptacles on the bottom and call it a day.
Well, they're easy to construct to find out. I cant imagine the stands doing anything to the bass; I just dont have the knowledge to interpret their effect. I couldnt make a statement like "you'll lose 3 db because the two ports are 10" up higher off the floor"...
I do recall the Valencia was mentioned as not being particularly ideal for the driver that's in it; others know things like that driver performs better in a different cabinet. I'd just assume Altec knew what they were doing in that era and wouldnt put into production a sub-optimal product. Live and learn. Perhaps they squeezed down a bit too much on that 15" volume wise, to get it to fit into some customers SAF and knew. Not everyone - even in "Valencia" California - has a gigantic house, with gigantic rooms. Oh, circa 1966; swimming pools, movie stars, big cars, cheap gas. "Liar-Liar" blasting out of 'em; room full of cute women dancing in mini skirts at the party. Owner happy.
It's be interesting to know what other manufacturers products they considered competition for this speaker and what kinds of spaces such a product was being put into, around the time it came on the market.
Re spacing...... a good enough guide for a 1st approximation is vent end corrections, though of course only measuring in room will yield an accurate min - max range, i.e. if we accept k = 2.227 as setting hard on the floor, then k = 0.732 is any gap between these two points based on the vent area = speaker H x W
Attachments
So I use to have these JBL240Ti, which I also wanted to lift due to the high crossover from woofer to mid; 900Hz. This means a major part of vocals will be eminating from the woofer, and at closer listening distances this felt problematic. I didn't build stands, but I tried lifting them by simle means.
This worked fine, I didn't feel I lost any bass, and I would have built stands similar to my tables if they had stayed. This room has concrete under the HDF flooring, and flooring/walls are decoupled. Another option would have been to keep them upright and slightly slanted backwards, and for this I would have made the L-stands. Maybe even better option, but I liked the direct sound from the big woofer, 900Hz gives it a lot of content. Given the different and unpredictable properties of rooms, experimenting before building is my way, I guess...
This worked fine, I didn't feel I lost any bass, and I would have built stands similar to my tables if they had stayed. This room has concrete under the HDF flooring, and flooring/walls are decoupled. Another option would have been to keep them upright and slightly slanted backwards, and for this I would have made the L-stands. Maybe even better option, but I liked the direct sound from the big woofer, 900Hz gives it a lot of content. Given the different and unpredictable properties of rooms, experimenting before building is my way, I guess...
As I mentioned - somewhere - the stands I built were sand filled chimney flue pipe cemented to a paver stone. They were heavy. I had some Dahlquist speaker upon them, which did improve things. On a hardwood oak floor over joists.