Unusual placement conundrum
Has anybody mounted acoustics on or in a wall? I have a room without any possibility of floor positioning (see pic). There is a large wall above the fireplace behind which is attic space. Is it feasible to mount my model 3s or 2s on-wall, or in-wall, with the back being open to the attic i.e. infinite baffle? If so should they be angled down or toed in. I will be using a minidsp to manage room effects, and, if necessary to control a sub. If mounted on the wall will this introduce diffraction issues? Any input is greatly appreciated.
Has anybody mounted acoustics on or in a wall? I have a room without any possibility of floor positioning (see pic). There is a large wall above the fireplace behind which is attic space. Is it feasible to mount my model 3s or 2s on-wall, or in-wall, with the back being open to the attic i.e. infinite baffle? If so should they be angled down or toed in. I will be using a minidsp to manage room effects, and, if necessary to control a sub. If mounted on the wall will this introduce diffraction issues? Any input is greatly appreciated.
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I spoke with Jim Strickland in the 80s...........Acoutats was here in Fl...Ft Lauderdale...at that time..............
about hanging panels......i was using one panel for right one for left...to hang in rears sround sound.......he said that thay had panels playing hanging from the sealeing....an thay sounded fine.....not as good as on the floor but still...............
An i have played 3 panels ea. side... just the panels leaning back about 10" off the floor....had a guy come over an he was freakout..........seid best sound he had ever heard.....he has two pr of Acoustats now......
Long ive Acoustat.........
about hanging panels......i was using one panel for right one for left...to hang in rears sround sound.......he said that thay had panels playing hanging from the sealeing....an thay sounded fine.....not as good as on the floor but still...............
An i have played 3 panels ea. side... just the panels leaning back about 10" off the floor....had a guy come over an he was freakout..........seid best sound he had ever heard.....he has two pr of Acoustats now......
Long ive Acoustat.........
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Infinite baffle would be perfect.
On the wall, only if you angle them leaving enough space for the back-wave to escape without reflecting straight back in to the panel.
Fortunately, with all old models being very directional (beaming), they like the heavy angling towards the listening postion, even as much as "crossing" the imaginary lines in front of you. In some cases (my room for example) they sound the best like that.
I kept the Model-3 pushed right into the corners as far as it would go at about 30 deg to the rear wall (60 deg to the side wall) for 15 years - it was the best I could do and they sounded excellent. On the down side, the sweet spot was about 10x10cm size. If your head is too big, you lose the HF response (ears are out of the sweet spot)
Fortunately the sound should be better than other options even for those not in the sweet spot. My 3s are in the middle of a very large room, with the back wall much further away than the listening position and the sound is fantastic. I am anticipating that with either in or on-wall, I'll need to keep the back open. My concern with on-wall is the diffraction that will be created at the edge of the speaker. Flush mounting them in the wall would avoid these issues.
Yes I went for 3ea 9"panels only flat............best sound i have ever had......worket for the old quad 57s..........Sander like the none dispershion flat sound...for me hes right...
Lot of people say the 1+1 was the best of the olders setups.......so i just puled them up of the ground an went with a 28"
...i had the 1+1s ...2+2...M3...M4s...
but this sounds the best.........big stage.......sweet sound...
Long like Acoustat....panels anyway
Lot of people say the 1+1 was the best of the olders setups.......so i just puled them up of the ground an went with a 28"
...i had the 1+1s ...2+2...M3...M4s...
but this sounds the best.........big stage.......sweet sound...
Long like Acoustat....panels anyway
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I believe the question remains unanswered, if you mount them in wall, you are creating an enclosure. The results are unpredictable, I think! I have experimented with two panels bolted together sealed, both in phase and out of phase, using servos and interfaces. Neither was worth my effort. I do not know of any one ever bragging about enclosing the back wave like a common driver.
I do know for a fact you will loose sensitivity, every time I over compensated for rear wave, absorption, I lost at least 3 db, your completely isolating the back wave which will be significant.
If you do this, please post the results for us all to refer in the future
Ed
I do know for a fact you will loose sensitivity, every time I over compensated for rear wave, absorption, I lost at least 3 db, your completely isolating the back wave which will be significant.
If you do this, please post the results for us all to refer in the future
Ed
By definition, if the speakers were mounted in a rigid wall with the front facing the room and the back facing outside you would have an infinite baffle design that would not be terribly different from setting the speakers in the middle of a very large room. I know that the latter arrangement does work. Likewise, mounting them on a wall, in front of a large hole, with the back facing a large room, such as an attic, essentially duplicates an infinite baffle. Subwoofers set up as an infinite baffle have demonstrated how this can be implemented. I agree that simply mounting the speakers on the wall will not work. What I don't know is how the speakers work in a "wide baffle" i.e. are they similar to conventional speakers? Imagine a scenario where the speakers are set up in an auditorium, well away from the walls, and a listener is positioned in front of them. Now add plywood walls to the sides and tops of the speakers, leaving the backs open. Will the listener perceive a change in the sound? This scenario will duplicate an in-wall or on-wall set up where there is nothing behind the speaker except open space. Of interest, is how big does the space behind the speaker have to be, and can this be diminished through proper insulation?
Yes, as soon as I get them refurbished I will give them a good comparance.
Though the bass is/will be better then the original, so it will not be a true comparance with a "pure" Spectra 11, but rather an updated Spectra 11 towards 1100 and more.
But it will be fun to compare to the rest of my collection!
Though the bass is/will be better then the original, so it will not be a true comparance with a "pure" Spectra 11, but rather an updated Spectra 11 towards 1100 and more.
But it will be fun to compare to the rest of my collection!
Your analysis is incorrect. If it were correct, then the speaker would work very little, if at all, and then only for a short time until the wall transformer melted. There is no complete circuit in that connection, and therefore no current flows.
The negative side of the high voltage supply, one side of the low voltage AC input, and the chassis are connected together for SAFETY reasons. The HV supply and the AC input are already connected on the PC board, and the chassis is connected via the wire. In the very unlikely event that the high voltage came into contact with either the chassis or the AC input, that high voltage would be shorted to that common connection (labeled ‘High Voltage Ground’ on the schematic), thereby eliminating any shock hazard.
No performance difference should occur with the wire connected or disconnected. It is there for safety reasons only, so the choice is yours as to reconnecting the wire to chassis.
The Spectra 22, 2200, 33, and 3300 all use the same interface. However, due to differences in the amount of bass equalization required for the different panel areas, the 22/2200 and 33/3300 are wired differently by using a different tap on the transformer bass-boost winding. These interfaces also include a switchable crossover for use with Acoustat's SPW-1 woofer module.
The Spectra 44, 4400, 66 and 6600 all use the same interface. They are different from the 22/33 series in that 1) they do not include the switchable crossover, and 2) they use a different low frequency transformer. Again, the interfaces for the 44/4400 and 66/6600 are wired with different bass taps.
As the Spectra Series represented all of Acoustat's accumulated learning, they already contain many of the improvements commonly applied to earlier models. So far, they also exhibit very good reliability, even better than some of the earlier MK-121-based models. So there's really nothing I can recommend in the way of sonic or reliability improvements.
Well, it would still work as the case is not truly grounded to any ground in the ground socket as the transformer is not grounded either.
So, the speaker chassis has a floating ground that will be connected to the transformers secondary winding with its half cycle of voltage output.
Now, what happens if my body gets grounded for whatever reason and I touch the chassis? Then I will close the circuit with a TRUE ground through my body.
This is also EXTREMELY noticable with ungrounded computers where the switched power supply will send half of the 240V/110V into the computers casing, hard drives and all that is connected to ground.
I had never ever any problems with this sitting on wooden floor until I moved and I got 110V into my body through the chassis and everything else that was connected to the computer because I had a grounded servise hatch on the floor that I stood on.
Not funny!
The secondary winding of an AC transformer has NO ground point to talk of as it will switch polarities between both taps.
It WOLD be different if there was a center tap on the transformer to be used as a ground and thus a 3rd cable.
Am I totally wrong?
Would gladly know!
Cheers!
2 + 2
Hello Andy:
I'm the original owner of a pair of 2 + 2's. They were in working condition when taken out of service about 7 years ago. They've been stored inside the entire time. I'd like to replace the grille cloths on them and put them back in service.
Is there anything I should be aware of/do to these first? It seems like now would be the time to do so.
Thanks.
Everett
Hello Andy:
I'm the original owner of a pair of 2 + 2's. They were in working condition when taken out of service about 7 years ago. They've been stored inside the entire time. I'd like to replace the grille cloths on them and put them back in service.
Is there anything I should be aware of/do to these first? It seems like now would be the time to do so.
Thanks.
Everett
Changing the grill socks is a tedious process, but with patience it's not that hard to do. The grill cloth is secured top and bottom with many staples, which must be carefuuly pried out of the wood.
Once you have the speaker unclothed, I'd recommend a thorough vacuuming and/or a gentle blast of compressed air to clean any debris from the panel. Do this to both sides of the panel. You may also find that the felt blocks on the rear of the panels are loose - these can be re-attached with contact adhesive. Also check that all of the panel mounting bolts are tight.
After cleaning the panels, I'd recommend operating the speaker for a while before applying new cloth. That way, if you run into any problems, they can be corrected without having to mess up that nice new cloth.
As long as the speakers were stored in a relatively clean environment, you shouldn't have any panel problems associated with long-term storage.
Next project…building slimmer frames for the Acoustat panels. I'm considering two options: either build a frame similar to the original one except slimmer or a frame without horizontal bars, with a narrower opening than the panel and then screw the panel directly to the frame. What would the downside be of the latter option?
What is the purpose of the felt on the back of the panel? Can it be removed if no horizontal bars are used?
I noticed there is a burn mark in the plastic about where the yellow/red cable is attached in the panel (see attached picture). Is it something to be worried about, and if so what can be done to fix it?
What is the purpose of the felt on the back of the panel? Can it be removed if no horizontal bars are used?
I noticed there is a burn mark in the plastic about where the yellow/red cable is attached in the panel (see attached picture). Is it something to be worried about, and if so what can be done to fix it?
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What model Acoustat are you working on? Also, what is your goal in making slimmer frames? Knowing what speaker you are rebuilding might help me to answer your questions, because so far your description leaves me guessing too much to be of any real assistance. If you are planing on a wooden frame, slimmer than original, then you may end up with a rather flimsy arrangement. A frame of metal (which has its own problems) may be slimmer and yet rigid enough.
The felt blocks on the rear of the panel are there to tame resonances. I recommend that they be retained, although some people have removed them and they are okay with the result.
The dark area around the bias feed wire may not be a burn mark - it's hard to tell from your photo. The panel does look like it has discolored quite a bit, which is not unusual: the high voltage tends to attract dust and especially smoke particles. The dark area may be just an accumulation of dirt, or it may even be a stray bit of conductive coating that got slopped on the edge of the panel during original manufacture. You might try cleaning the area with a mild soap and barely-wet rag. Otherwise, I wouldn't worry about it too much unless there are signs of actual burnt plastic or charred insulation on the bias feed wire. There have been virtually no reports of problems in the bias-feed area.