It is an interesting concept. Another spin on the topic is to realize that the drivers are acting as microphones. They will generate a signal which they feed back into the amp. An amp with a low dampening factor will have this signal interfering and distorting the performance. We actually hear the room reflection in a feedback loop of sorts.
Ŵhen you ha e a subwoofer connected tò a AVR an set GG the crossover say set to 80 Hz frequencies below 80 Hz are takenover from the front pair and redirected to the subwoofer or subwoofers , so if you were to turn off the power to your single or allyour Subs and the crossover builtin the AVR is still set to 80 Hz , your front paìr are then only reproducing bass above the crossover point , this also depends on how your sysystem is setup you may be running subs with builtin crossovers and your fronts may be running full range. So ok you cut the power to all the Subs and you then have maybe 4 subs with uncontroled cones .
It might be more accurate to say the unused sub is a resonant chamber that can add as well as absorb. And as you mention, leaving the sub powered but no signal will reduce any such interaction because of the amp's Damping Factor affect on the driver.
In the late 70’s the Bose rep told us that if we wanted to continue being Bose dealers we had to “bare a wall for Bose”. No other speakers could be on the same wall in the room. It certainly had the effect of absorbing the sales of other speaker brands!!
Why am i not surprised. The slight respect I ever have for Bose's marginally better than horrid products, gets negated by their shady marketing tactics. Intelligent consumers are constantly being encouraged by Bose themselves to hate on the company- as if the concept of "direct/reflected" in the realm of reproducing a stereo signal wasnt plenty already.
There are some room acoustic devices the size of a quarter that you stick them on a different places on the wall, and some audiophiles claim that they do have an effect on the sound quality, so if those tiny things can make a difference, than a big woofer in a box certainly can.
Yeah but the difference is that those quarter size “devices” don’t actually have an audible effect. Maybe if you’re talking hundreds+ placed in a given room but no one’s and I mean not one single person’s ears on this planet are good enough to detect an audible difference from just 1 or 5 or even 50 of those things. Never in a million years could someone sit blindfolded and be able to detect a difference as just a few were added. Big subs sitting idle on the other hand could possibly effect the room enough to detect an audible difference but I’d say even then in most cases you’d have to have better than average hearing to be able to sit blindfolded and tell when the subs were added or subtracted from the space. “Audiophiles” give human beings credit for having way better hearing then we actually do. I’ve proven this point time and time again over the years with my own system which is highly resolving. I’ve yet to encounter anyone that could actually pick out subtle differences in anything that minuscule when put on the spot. I’ve encountered quite a few people who claimed such nonsense but not one who could actually deliver on said claims.
As an AV integrator, everything in the room absorbs sound and /or reflects it. From the walls to the floor, chairs, your body and yes even the speaker itself. If you have parallel walls and speakers shooting at them, the sound amplitude increases, clarity decreases. Anything that helps break up those frequencies which helps standing waves from compounding, will always make a room sound better. Sometimes subs can be a bit pronounced and the room gets very "boomy", if you can't find the right medium on setting up the sub, You can combat that with another sub slightly out of phase.
Two further questions: 1) so powering the sub’s amp with the volume up but with no input “steadies” the sub cone? 2) How bad is this effect in a room with dozens of drivers typical in many bricks-and-mortar audio store listening rooms?
I drove from upstate SC to Buffalo NY to pick up a pair of JVC SK 1000’s. Point is on the way back my factory car stereo sounded different with these 50 lb speakers in the trunk not powered up of course. I thought the car stereo sounded better base wise. Was it just because different is better or just because it changed the space in the trunk where the rear car speakers are housed? Or was it the speakers, who knows?
More than likely it was the space in the trunk with your setup. Are you using 6X9’s. Space in car audio is much different than home audio. Sound waves can bounce around in car audio. Sound waves can and do go backwards in the trunk with your setup. I am guessing you might be using 6X9’s. I used 6X9’s back in the late 80’s. I had them in speaker boxes. With a 75 x 2 RMS amplifier. JVC head unit. Both made in Japan. 👍 ❤😍🤗😎👍🥰
@@davidfromamerica1871 their factory Altima speakers might be 6 x 8’s, but I agree the house speakers in the trunk just decreased the volume in the trunk space.
As Paul says the effect is minimal but there was this one time when I got a broken speaker to vibrate sympathetically to the sound waves and that sounded terrible. Was hunting around for the source for a while.
I'm not sure why with the amp on, the speaker is held still but not with the amp off. If it is connected to the amp, isn't there a low impedance connected to the speaker of the amp's output transistors? If you connect a wire across a speaker's terminals it will resist motion as the speaker becomes a linear generator, that generates a current that magnetizes the coil in the opposite direction to your push. Do some amps disconnect the speakers e.g. to prevent power on pops? Though I think I did try it with a couple of amps of mine and the speaker was flexible with the amp off and more rigid with the amp on.
There is also a Texas in Queensland Australia. It's a small town. I believe the real reason for not wanting other speakers in the room is to prevent A B switching tests.
When I'm using my subwoofer next to my disconnected JBL LX55 speakers, the woofers vibrate a little bit, and cause a faint crackling sound to come out of the tweeters. Weird.
Well i bet that was PITA but vibrating strings are of course a whole nother animal. Not so much absorbing the bass energy but filling the air with hundreds of additional sounds at various frequencies. Its a situation so bad Im surprised the issue isnt more well discussed. Then again if its a quality instrument one might enjoy the additional constant ambience coloring all their music. A grand piano is inherently one of the most beautiful things to listen to. The Roxette song "listen to your heart" was covered some years ago by a Belgian group with a female singer accompanied only by a piano. It became a huge hit worldwide with a sound I could only describe as stripped down and honest. Music from a hundreds of years old instrument still relevent today.
As Paul said, the effect is too small to worry about. Helmholtz resonators have to be tuned in large groups to have a noticable or even measurable effect.
@@wty1313 Almost true, although I have tried with a 5 l empty water bottle. There's a half decibel difference at the measured frequency with the cap. Not much for one plastic bottle, but enough to the measured by the sonometer.
I think the question is 'Does an unused speaker system function as a Helmholtz resonator type of sound absorber?' The answer given is 'Probably, Yes!'. The enclosure is resonant at some definite frequency. So does the empty vase beside the armchair act as an absorber at a frequency.
Paul indirectly gives the answer @2:48: "the amplifier holds it still" - so all one needs to do is leave the subwoofer on and unplug its input (preferably on the preamp side in order not to create an antenna). Not the most economical way to go about it as it'll consume electricity being idle, but the damping factor of the subwoofer is effectively going to counteract any sound waves from passively moving the sub driver cone.
Same effect would occur. Anything that is a sealed cavity with one end open to the sound pressure in the room will act as a Helmholtz resonator - including an open bottle of beer, BUT the effect will be very small because the effect will be spread across a very wide frequency range due to the various sizes, etc. Helmholtz resonators have to be tuned in a fairly large group to have significant effect which is why it's rarely used in real life applications.
Any piece of furniture with thin-sh panels or plaster board walls will absorb and radiate sound at far higher levels than any loose drivers in the room.
I’ve noticed that if I stand up, my ass absorbs far more bass than any subwoofer. If I lose weight, the trapped frequencies would be higher, and I much prefer trapping the lower frequencies. That’s my story and I’m sticking to it.
I would bet that speaker company’s reasoning had more to do with they didn’t want the person who was receiving the demonstration to have any other speaker to compare theirs to (A vs B) in that room. For better, or for worse, they wanted theirs to stand on its own and not be part of some sort of dealer shoot out.
The first thing you notice is the “Baffles” inside the cabinet, that is what fine tunes all speakers, including Subwoofers. You have to know what you are doing in baffle design to get it right. czcams.com/video/q2IvlqMaH4U/video.html
The only problem I had with a sub is hearing damage.😀 If you have it, you are going to use it..🤗 I had my sub set to 20 Hz in a customized baffled ported box for rock and heavy metal. Hooked to a amplifier that had “lots” of headroom for that sub. Enormous amount of air pressure coming out from that sub. No more sub for me. Save what hearing I have left. 😀
@@sudd3660 Speaker Air Pressure the bass carries does damage your hearing. The same with headphones. The air pressure bass inside the headphones is even worse. You must be one of these elite Audiophile Audiologist. 😀😀😀😀😀😀😀😀😀
@@davidfromamerica1871 well unless you are sticking your ear to the port it doesn't do that much damage (at least not to the hair cells in the cochlea). It does encourage you to turn the mids and highs louder though, so indirectly yes.
I don’t know I use pro and studio subs they don’t take away bass just add too much now I need all 15 inch and bigger pa speakers to keep up with the bass for now I have my highs eq higher than 0 db to help with that
you said "too much". check its back there must be a knob... haaa. turn it back till is ok man. all that in a room? or you are doind PA? in a room is nuts and a mess.. you are killing your hearing mate.
saw your profile photos and short videos.. you are doing it wrong.. using big pa speakers as desktop studio monitors ..no no no.. save all that for PA and buy a good pair of studio monitor speakers. you will listen more and better taking care of your ears. for what you said and what i saw you are hearing bad audio too powerful and killing your ears. save some hearing for your older years pal. see ya.
@@shangrilaladeda well. dont thank me for watching your videos .. if you wanna thank me do it for the piece of advice i gave you. save your hearing you will need it in years to come.
What frequencies would be absorbed by a woofer driver/cabinet? If it's a 12" driver, one wavelength at this woofer diameter corresponds to about 1.2 kHz I would be more concerned about the mid-range frequencies and higher, being affected or absorbed by a standard sub-woofer rather than the lower frequencies which have very long wavelengths - often wavelengths that are comparable to the size of the listening room. Overall, I wouldn't be concerned with a subwoofer selectively absorbing or trapping specific sound frequencies. It would be an interesting scientific investigation though
Somebody needs to tell Glenn that a passive radiator *is not* a "driver"! I'm sure there are some folks here that are old enough to remember when they were called "drone cones"?
Someone needs to tell digggerr jones that the description of "Dual Drive" comes directly from the manufacturer (Proficient Audio) for my FS-8 subwoofer, lol :)
Area of 8" woofer = 0.3491 sq ft. Surface area of 12 x 14 x 9 room: 636.0 sq ft. Ratio of woofer to room: 0.0006197 or 0.06%. Draw your own conclusions?
The only frequencies the sub will absorb are the frequencies that are in the sub's range, which is directly related to the size of the sub driver. The satellite speakers don't go down deep enough to have any audible effect. Not only that, but it's a useless question to ask, because a simple experiment will answer it...just take the sub out of the room and see if you hear any audible difference. If it isn't audible, then the question is moot.
🤔Does a typically impractical technical question posed by the technically ignorant require an answer, ludicrous or otherwise ? Pragmatism should always trump any minor technicalities in audio matters. Ok, I’ll go back to dreaming of a world devoid of entertaining stupidity. 😵💫
It is an interesting concept. Another spin on the topic is to realize that the drivers are acting as microphones. They will generate a signal which they feed back into the amp. An amp with a low dampening factor will have this signal interfering and distorting the performance. We actually hear the room reflection in a feedback loop of sorts.
Ŵhen you ha e a subwoofer connected tò a AVR an set GG the crossover say set to 80 Hz frequencies below 80 Hz are takenover from the front pair and redirected to the subwoofer or subwoofers , so if you were to turn off the power to your single or allyour Subs and the crossover builtin the AVR is still set to 80 Hz , your front paìr are then only reproducing bass above the crossover point , this also depends on how your sysystem is setup you may be running subs with builtin crossovers and your fronts may be running full range. So ok you cut the power to all the Subs and you then have maybe 4 subs with uncontroled cones .
It might be more accurate to say the unused sub is a resonant chamber that can add as well as absorb. And as you mention, leaving the sub powered but no signal will reduce any such interaction because of the amp's Damping Factor affect on the driver.
In the late 70’s the Bose rep told us that if we wanted to continue being Bose dealers we had to “bare a wall for Bose”. No other speakers could be on the same wall in the room. It certainly had the effect of absorbing the sales of other speaker brands!!
Why am i not surprised. The slight respect I ever have for Bose's marginally better than horrid products, gets negated by their shady marketing tactics. Intelligent consumers are constantly being encouraged by Bose themselves to hate on the company- as if the concept of "direct/reflected" in the realm of reproducing a stereo signal wasnt plenty already.
The real reason Bose requested that was their speakers usually were outperformed when compared with other highly regarded speakers.
There are some room acoustic devices the size of a quarter that you stick them on a different places on the wall, and some audiophiles claim that they do have an effect on the sound quality, so if those tiny things can make a difference, than a big woofer in a box certainly can.
Yeah but the difference is that those quarter size “devices” don’t actually have an audible effect. Maybe if you’re talking hundreds+ placed in a given room but no one’s and I mean not one single person’s ears on this planet are good enough to detect an audible difference from just 1 or 5 or even 50 of those things. Never in a million years could someone sit blindfolded and be able to detect a difference as just a few were added. Big subs sitting idle on the other hand could possibly effect the room enough to detect an audible difference but I’d say even then in most cases you’d have to have better than average hearing to be able to sit blindfolded and tell when the subs were added or subtracted from the space. “Audiophiles” give human beings credit for having way better hearing then we actually do. I’ve proven this point time and time again over the years with my own system which is highly resolving. I’ve yet to encounter anyone that could actually pick out subtle differences in anything that minuscule when put on the spot. I’ve encountered quite a few people who claimed such nonsense but not one who could actually deliver on said claims.
It’s obvious you don’t have Audiophile ears that can hear grass growing. 🙄
@@davidfromamerica1871
Yep. Just like the rest of us😉
As an AV integrator, everything in the room absorbs sound and /or reflects it. From the walls to the floor, chairs, your body and yes even the speaker itself. If you have parallel walls and speakers shooting at them, the sound amplitude increases, clarity decreases. Anything that helps break up those frequencies which helps standing waves from compounding, will always make a room sound better. Sometimes subs can be a bit pronounced and the room gets very "boomy", if you can't find the right medium on setting up the sub, You can combat that with another sub slightly out of phase.
When installed Paul, give us a nice little tour of this listening room😎
Two further questions: 1) so powering the sub’s amp with the volume up but with no input “steadies” the sub cone? 2) How bad is this effect in a room with dozens of drivers typical in many bricks-and-mortar audio store listening rooms?
Theoretically this could be used to one's advantage by placing carefully tuned speakers to reduce key room resonances.
I drove from upstate SC to Buffalo NY to pick up a pair of JVC SK 1000’s. Point is on the way back my factory car stereo sounded different with these 50 lb speakers in the trunk not powered up of course. I thought the car stereo sounded better base wise. Was it just because different is better or just because it changed the space in the trunk where the rear car speakers are housed? Or was it the speakers, who knows?
More than likely it was the space in the trunk with your setup. Are you using 6X9’s.
Space in car audio is much different than home audio. Sound waves can bounce around in car audio. Sound waves can and do go backwards in the trunk with your setup. I am guessing you might be using 6X9’s.
I used 6X9’s back in the late 80’s.
I had them in speaker boxes.
With a 75 x 2 RMS amplifier.
JVC head unit. Both made in Japan. 👍
❤😍🤗😎👍🥰
@@davidfromamerica1871 their factory Altima speakers might be 6 x 8’s, but I agree the house speakers in the trunk just decreased the volume in the trunk space.
Less air space, and an absorbing medium. (ie; the speakers)
As Paul says the effect is minimal but there was this one time when I got a broken speaker to vibrate sympathetically to the sound waves and that sounded terrible. Was hunting around for the source for a while.
I think it could be minimal effected with a closed sub but not with a ported sub?
I'm not sure why with the amp on, the speaker is held still but not with the amp off. If it is connected to the amp, isn't there a low impedance connected to the speaker of the amp's output transistors? If you connect a wire across a speaker's terminals it will resist motion as the speaker becomes a linear generator, that generates a current that magnetizes the coil in the opposite direction to your push. Do some amps disconnect the speakers e.g. to prevent power on pops? Though I think I did try it with a couple of amps of mine and the speaker was flexible with the amp off and more rigid with the amp on.
There is also a Texas in Queensland Australia. It's a small town.
I believe the real reason for not wanting other speakers in the room is to prevent A B switching tests.
What a strange question, but mind blowing that someone would notice the difference on an 8" sub no less!
Dispelling myths and giving relevant information every day.
In audio stores, they have dozens of speakers and subs out on display, often in the listening room. They don't worry about it so you shouldn't either.
When I'm using my subwoofer next to my disconnected JBL LX55 speakers, the woofers vibrate a little bit, and cause a faint crackling sound to come out of the tweeters. Weird.
Subwoofers are a strange beast. 😀 There are lots of people that will never use a subwoofer in their system.
I once had a piano in my small music room and that was a killer. Once piano out wow big difference but a sub nahhhh I Agreeeee with Paul .
Well i bet that was PITA but vibrating strings are of course a whole nother animal. Not so much absorbing the bass energy but filling the air with hundreds of additional sounds at various frequencies. Its a situation so bad Im surprised the issue isnt more well discussed.
Then again if its a quality instrument one might enjoy the additional constant ambience coloring all their music. A grand piano is inherently one of the most beautiful things to listen to.
The Roxette song "listen to your heart" was covered some years ago by a Belgian group with a female singer accompanied only by a piano. It became a huge hit worldwide with a sound I could only describe as stripped down and honest. Music from a hundreds of years old instrument still relevent today.
There is also Ontario, Oregon, along the border with Idaho and I-84.
That interesting. If that is happening, I’ve never heard that effect (even with several large inactive speakers in the room).
As Paul said, the effect is too small to worry about. Helmholtz resonators have to be tuned in large groups to have a noticable or even measurable effect.
@@wty1313 Almost true, although I have tried with a 5 l empty water bottle. There's a half decibel difference at the measured frequency with the cap. Not much for one plastic bottle, but enough to the measured by the sonometer.
I think the question is 'Does an unused speaker system function as a Helmholtz resonator type of sound absorber?'
The answer given is 'Probably, Yes!'. The enclosure is resonant at some definite frequency. So does the empty vase beside the armchair act as an absorber at a frequency.
Paul indirectly gives the answer @2:48: "the amplifier holds it still" - so all one needs to do is leave the subwoofer on and unplug its input (preferably on the preamp side in order not to create an antenna). Not the most economical way to go about it as it'll consume electricity being idle, but the damping factor of the subwoofer is effectively going to counteract any sound waves from passively moving the sub driver cone.
What about a HiFi store showroom with all those not playing speakers?
Same effect would occur. Anything that is a sealed cavity with one end open to the sound pressure in the room will act as a Helmholtz resonator - including an open bottle of beer, BUT the effect will be very small because the effect will be spread across a very wide frequency range due to the various sizes, etc. Helmholtz resonators have to be tuned in a fairly large group to have significant effect which is why it's rarely used in real life applications.
Subs can decrease the bass of other subs and speakers by cancelling certain frequencies while playing music as well.
I like Linn products but they were so hard-core about this they wouldn’t allow an old style telephone in the room.
I like to believe that "single speaker" policies are imposed to prohibit A/B comparisons
that Just Might Not Favour Certain Products.
Any piece of furniture with thin-sh panels or plaster board walls will absorb and radiate sound at far higher levels than any loose drivers in the room.
Paul..... You just ain't putting enough juice to your sub 😂
I’ve noticed that if I stand up, my ass absorbs far more bass than any subwoofer. If I lose weight, the trapped frequencies would be higher, and I much prefer trapping the lower frequencies. That’s my story and I’m sticking to it.
Onkyo receiver my subwoofer work then loose sound
I would bet that speaker company’s reasoning had more to do with they didn’t want the person who was receiving the demonstration to have any other speaker to compare theirs to (A vs B) in that room. For better, or for worse, they wanted theirs to stand on its own and not be part of some sort of dealer shoot out.
When you use 2 and put them out of phase with eachother
You right brother. Out of phase subs will eat bass. I've done this by mistake.
There’s an Ontario in Ohio too, just for the record.
They call it sympathetic resonance 😊
What if you have a complete wall of speakers in the room. Like 40 pair of speakers in the room!
The first thing you notice is the “Baffles” inside the cabinet, that is what fine tunes all speakers, including Subwoofers. You have to know what you are doing in baffle design to get it right.
czcams.com/video/q2IvlqMaH4U/video.html
The only problem I had with a sub is hearing damage.😀
If you have it, you are going to use it..🤗 I had my sub set to 20 Hz in a customized baffled ported box for rock and heavy metal. Hooked to a amplifier that had “lots” of headroom for that sub.
Enormous amount of air pressure coming out from that sub. No more sub for me. Save what hearing I have left. 😀
bass do not hurt hearing.
@@sudd3660
Speaker Air Pressure the bass carries does damage your hearing. The same with headphones. The air pressure bass inside the headphones is even worse.
You must be one of these elite Audiophile Audiologist.
😀😀😀😀😀😀😀😀😀
@@davidfromamerica1871 well unless you are sticking your ear to the port it doesn't do that much damage (at least not to the hair cells in the cochlea). It does encourage you to turn the mids and highs louder though, so indirectly yes.
OMG
Wow this question was really in the weeds
I don’t know I use pro and studio subs they don’t take away bass just add too much now I need all 15 inch and bigger pa speakers to keep up with the bass for now I have my highs eq higher than 0 db to help with that
you said "too much". check its back there must be a knob... haaa. turn it back till is ok man.
all that in a room? or you are doind PA? in a room is nuts and a mess.. you are killing your hearing mate.
saw your profile photos and short videos.. you are doing it wrong.. using big pa speakers as desktop studio monitors ..no no no.. save all that for PA and buy a good pair of studio monitor speakers. you will listen more and better taking care of your ears.
for what you said and what i saw you are hearing bad audio too powerful and killing your ears. save some hearing for your older years pal. see ya.
@@endrizo thank you for watching some of my videos
@@shangrilaladeda well. dont thank me for watching your videos .. if you wanna thank me do it for the piece of advice i gave you. save your hearing you will need it in years to come.
@@endrizo I’m nearly 40 years old I don’t want to be around for much longer life is shit
Loads of subwoofers go for sale haha.
What frequencies would be absorbed by a woofer driver/cabinet?
If it's a 12" driver, one wavelength at this woofer diameter corresponds to about 1.2 kHz
I would be more concerned about the mid-range frequencies and higher, being affected or absorbed by a standard sub-woofer rather than the lower frequencies which have very long wavelengths - often wavelengths that are comparable to the size of the listening room.
Overall, I wouldn't be concerned with a subwoofer selectively absorbing or trapping specific sound frequencies. It would be an interesting scientific investigation though
Somebody needs to tell Glenn that a passive radiator *is not* a "driver"!
I'm sure there are some folks here that are old enough to remember when they were called "drone cones"?
Someone needs to tell digggerr jones that the description of "Dual Drive" comes directly from the manufacturer (Proficient Audio) for my FS-8 subwoofer, lol :)
Remove the CURTAINS and CARPETS of any room… and don’t tell me u can’t hear a difference!!
Area of 8" woofer = 0.3491 sq ft. Surface area of 12 x 14 x 9 room: 636.0 sq ft. Ratio of woofer to room: 0.0006197 or 0.06%. Draw your own conclusions?
The only frequencies the sub will absorb are the frequencies that are in the sub's range, which is directly related to the size of the sub driver. The satellite speakers don't go down deep enough to have any audible effect. Not only that, but it's a useless question to ask, because a simple experiment will answer it...just take the sub out of the room and see if you hear any audible difference. If it isn't audible, then the question is moot.
Speakers in a room not in use are acting more like reflectors and diffusers than absorbers.
Stupid question 🥴sorry
There's no such thing as a stupid question, when asked with sincerity. Facetious, small-minded comments like yours however, are two a penny.
🤔Does a typically impractical technical question posed by the technically ignorant require an answer, ludicrous or otherwise ? Pragmatism should always trump
any minor technicalities in audio matters. Ok, I’ll go back
to dreaming of a world devoid of entertaining stupidity. 😵💫