This could be a simple rotary system attached to a wall which makes it wobble a bit. Nothing difficult to this really.
A slow rotating motor with a concentric weight can do this. regulate it at a rotation from 120 to 900 rpm (2hz - 15hz)
Factory workers have been reported getting sick on the job and after extensive investigation, there was a resonance caused by a large machine. They had to put the machine on special surface or feet I think.
B.
A slow rotating motor with a concentric weight can do this. regulate it at a rotation from 120 to 900 rpm (2hz - 15hz)
Factory workers have been reported getting sick on the job and after extensive investigation, there was a resonance caused by a large machine. They had to put the machine on special surface or feet I think.
B.
I've got some 45-lb a piece TC Sounds woofers. What's the most reasonable front face depth that you would use?
I was thinking either 2-inch thick plywood or since I have access to a metal machinist a one-inch thick aluminum plate.
Any ideas on driver mounting for something that heavy?
I need to get this project done before my buddy gets married in October. After that I'm afraid the new wife will put an end to the massive sub box project getting deployed.
Since I have two of these 12" TC drivers, would it be better to build them into the same box or have two sub boxes?
I could stack two sub boxes or I could place them in different locations.
Also, anyone hear of Rhino coating a sub box? Any reason to use lots of car deadening mat on one? I'm thinking its probably a waste of money since the plywood box's resonant frequency is probably much higher than the sub will be operated at. I think I heard plywood boxes typically resonant higher than MDF at something like 2000hz.
I was thinking either 2-inch thick plywood or since I have access to a metal machinist a one-inch thick aluminum plate.
Any ideas on driver mounting for something that heavy?
I need to get this project done before my buddy gets married in October. After that I'm afraid the new wife will put an end to the massive sub box project getting deployed.
Since I have two of these 12" TC drivers, would it be better to build them into the same box or have two sub boxes?
I could stack two sub boxes or I could place them in different locations.
Also, anyone hear of Rhino coating a sub box? Any reason to use lots of car deadening mat on one? I'm thinking its probably a waste of money since the plywood box's resonant frequency is probably much higher than the sub will be operated at. I think I heard plywood boxes typically resonant higher than MDF at something like 2000hz.
1: not neccessary. Use good play and brace the hell out of the box. Much more effective than simply thick panels.Daveis said:
2: Brace the cabinet internally, and make one of the internal braces with a hole positioned and sized to accespt the magnet with it in place. I do this with heavy compression drivers on flares and it works well even with the rough treatment a gigging rig gets. It can be a bit fiddly to get it right the first time.
Also, if it's <80Hz only, raise the box a couple of inches and fire the driver to the floor.
3: I use truck bed liner type products on MI/PA cabinets and it's tough. Don't think it makes a difference to box panel resonances as I brace a lot anyway and use good ply.....
It can be a domestically challenging look.
I built a box with Peerless 12" passive radiators and TC-Sounds SVC 12" aluminum drivers.
The box internal volume ended up being about 6.5 cu feet.
The passive radiators are tuned to 10.5 hz supposedly.
We did a sine sweep from 20-200 hz and there is strong room vibration at 50 and 150hz. Bass trails off under 30hz.
But at 22hz just one of the passive radiators makes a clicking/clacking sound. (although at times I hear the sound from the driver closest to the passive, my friend says its clearly coming from the passive radiator; his head right in front of it)
Could a passive radiator (830548 12" XLS 425g Passive Radiator) be defective? I didn't even think to check to see how the cone mass was attached and whether it might be loose.
I was expecting stronger bass around 20hz. Should I decrease the internal box volume by placing some wood blocks inside?
We were watching the movie Casino Royale(2006) and there's s seen where Bond breaks into M's house. He's playing with a cell phone and there's background mood music with a heartbeat kind of sound. It's low, but not particularly loud.
I can hear the wall vibrating almost the same frequency as the clicking sound. Is it normal to hear quiet low frequency sound under 20hz as a clicking?
Another thing... the box has some internal cross bracing and a few shelf braces. But there's no stuffing. Should I pack the box with heavy fill?
The box internal volume ended up being about 6.5 cu feet.
The passive radiators are tuned to 10.5 hz supposedly.
We did a sine sweep from 20-200 hz and there is strong room vibration at 50 and 150hz. Bass trails off under 30hz.
But at 22hz just one of the passive radiators makes a clicking/clacking sound. (although at times I hear the sound from the driver closest to the passive, my friend says its clearly coming from the passive radiator; his head right in front of it)
Could a passive radiator (830548 12" XLS 425g Passive Radiator) be defective? I didn't even think to check to see how the cone mass was attached and whether it might be loose.
I was expecting stronger bass around 20hz. Should I decrease the internal box volume by placing some wood blocks inside?
We were watching the movie Casino Royale(2006) and there's s seen where Bond breaks into M's house. He's playing with a cell phone and there's background mood music with a heartbeat kind of sound. It's low, but not particularly loud.
I can hear the wall vibrating almost the same frequency as the clicking sound. Is it normal to hear quiet low frequency sound under 20hz as a clicking?
Another thing... the box has some internal cross bracing and a few shelf braces. But there's no stuffing. Should I pack the box with heavy fill?
As a diagnosis for rubbing drivers or passive radiator suspension, I'd turn the box to see if having any of the units firing up or down changes the clacking.
There are lots of recordings (at least from the Age of Vinyl) that have subway sounds and you can probably hear people farting in the control room of CDs if you listen for it. If you have infrasonic capabilities, good to be able to turn them off. As with records, the folks making CDs today may not know what infrasonics they are selling you - although I suppose they ought to be conscientious in doing LF filtering.
A friend had subs coming in below his Klipschs (a very good idea). But he could turn them off except for that exceptional special effect. I wonder if movie theatres do that?
Shaking buildings and making real potent (that is, "visceral") infrasonics takes big power and monumental speaker displacements (unless your sound source has hit and remained on a narrow resonant frequency.... as will happen with slow sweep testing that shakes windows and walls at certain frequencies).
Final thought. I was fixing my woofer amp a few weeks ago. So the system had a fairly sharp drop below 140 Hz. Hard to believe how little difference it made. Readily detectable on some sources, of course, but musically marginal. I hate to mention this.
There are lots of recordings (at least from the Age of Vinyl) that have subway sounds and you can probably hear people farting in the control room of CDs if you listen for it. If you have infrasonic capabilities, good to be able to turn them off. As with records, the folks making CDs today may not know what infrasonics they are selling you - although I suppose they ought to be conscientious in doing LF filtering.
A friend had subs coming in below his Klipschs (a very good idea). But he could turn them off except for that exceptional special effect. I wonder if movie theatres do that?
Shaking buildings and making real potent (that is, "visceral") infrasonics takes big power and monumental speaker displacements (unless your sound source has hit and remained on a narrow resonant frequency.... as will happen with slow sweep testing that shakes windows and walls at certain frequencies).
Final thought. I was fixing my woofer amp a few weeks ago. So the system had a fairly sharp drop below 140 Hz. Hard to believe how little difference it made. Readily detectable on some sources, of course, but musically marginal. I hate to mention this.
I found the complete opposite.bentoronto said:
Turn off the two channel upperbass through to treble and the tiny amount of signal being reproduced by the bass/sub-bass speaker seemed so quiet, one asks the question, "what is it contributing".
Now switch on the full speaker signal again and the music sounds normal.
Switch off that tiny Sub-bass/bass speaker and listen to just the upper bass and above and the music sounds different, sometimes completely different, to the point of unlistenable.
I do not like that thumping bass heard at most concerts and discos.
I do not like male voice to have that horrible bass enhanced "artificitial" tone.
But, I cannot live with a system that cuts off or attenuates the low bass frequencies. These low frequencies are, in whatever proportion is appropriate, indispensable to the full enjoyment of the music/sound track.
"Switch off that tiny Sub-bass/bass speaker and listen to just the upper bass and above and the music sounds different, sometimes completely different, to the point of unlistenable."
"Unlistenable," eh?
I don't know if we are talking about the same bass crossover - 140 Hz in my case. If we are, I have to say our observations are really different. And that's about as polite as I can be.
"Unlistenable," eh?
I don't know if we are talking about the same bass crossover - 140 Hz in my case. If we are, I have to say our observations are really different. And that's about as polite as I can be.
Well, would it be above or below the polite threshold to ask if Andrew T was speaking speculatively based on some concept or theory or was it based on his actual listening?
And if based on theory, I suppose it wasn't the well-accepted theory that the brain readily re-inserts the bass sounds that are absent? The brain does not really restore sternum shaking or the visceral experience of bass, but if the upper range is handled well, the lower partials sure "sound" fine... up to a point, of course.
And if based on theory, I suppose it wasn't the well-accepted theory that the brain readily re-inserts the bass sounds that are absent? The brain does not really restore sternum shaking or the visceral experience of bass, but if the upper range is handled well, the lower partials sure "sound" fine... up to a point, of course.
I am talking about a pair of Acoustic Energy AE1s with an active L-R 4pole 150Hz HP filter in front of the power amps and a modified Tannoy B950 fed from an L-R 4pole 150Hz LP filter in front of it's power amp (summed stereo channel).bentoronto said:
Turning off the bass speaker amplifier to leave the frequencies of 150Hz and above, ruins the sound effect.
Turning off the upper amplifiers leaves a tiny volume of bass sound effect that defies my attempts to explain why such a small signal should have such a big effect.
Interesting. Though I'd expect there to be a fair bit going on at 50-150Hz. Look how much of a piano you'd lose if you were filtering sounds below 150Hz (http://en.wikipedia.org/wiki/Piano_key_frequencies). I know LR4 isn't a brick wall, but even then...
What types of music are you finding shows the issue the most?
What types of music are you finding shows the issue the most?
