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Official Subwoofer thread
https://forum.lddb.com/viewtopic.php?f=27&t=2442		 Page 2 of 4
Author:  jdeavs [ 22 Nov 2013, 03:45 ]
Post subject:  Re: Official Subwoofer thread
alien wrote:
This is nothing to do with Laserdisc, but cam anyone tell me why my subwoofer makes clicking noises? The clicks aren't loud and they don't happen all of the time, but they do pop up particularly in a scene where the actual subwoofer itself kicks in.


It might be that the sub is on an auto on/off setting, and there's enough time between low-freq information that the sub goes into a standby mode, then you hear it click on to full power with the low sounds starting back up. If it happens along with ongoing sounds, you might have loose debris coming in contact with the cone (could also be wiring or a tie-wrap bundled around wiring), or a damaged or mis-aligned voice coil on the driver itself. More details or an audio recording could help.

je
Author:  elieb [ 22 Nov 2013, 05:25 ]
Post subject:  Re: Official Subwoofer thread
should i be worried about an underpowered sub when calibrating a new avr?
(pioneer has the MCCAC, which cranks the volume to 0db and sub tones at -30db, my sub is 100 watts)
Author:  kris [ 22 Nov 2013, 11:34 ]
Post subject:  Re: Official Subwoofer thread
elieb wrote:
should i be worried about an underpowered sub when calibrating a new avr?
(pioneer has the MCCAC, which cranks the volume to 0db and sub tones at -30db, my sub is 100 watts)


Caution,

For some subs the 12o clock position isn't always the right choice when calibrating...
I've had similar results with audyssey the first time. leaving the sub at -30
I've adjusted the sub level to the 10-11o clock position and audyssey calibrated the sub to -3db now.
Sound great and controlled now :thumbup:
It all blends in now without sub location troubles
Author:  invenio [ 22 Nov 2013, 15:21 ]
Post subject:  Re: Official Subwoofer thread
alien wrote:
This is nothing to do with Laserdisc, but cam anyone tell me why my subwoofer makes clicking noises? The clicks aren't loud and they don't happen all of the time, but they do pop up particularly in a scene where the actual subwoofer itself kicks in.


Doesn't sound right to me. How loud are you playing the sub, if the cone has detached from the housing it can make a "rattle" noise. How old is the sub, this can happen with older subs where the adhesive starts to crack around the cone. As substance pointed out, you can get a "thud" with the sub turning on but it should only happen when you first start playing something and then if you have a very long extended period of no signal (the sub then turns off). This should only happen at the beginning of a listening session and not again. Try turning off the "auto off/on" and see if it happens. If it still does, then it's not the "auto off/on" function.

Let us know what's happening.
Author:  elieb [ 22 Nov 2013, 23:28 ]
Post subject:  Re: Official Subwoofer thread
kris wrote:
elieb wrote:
should i be worried about an underpowered sub when calibrating a new avr?
(pioneer has the MCCAC, which cranks the volume to 0db and sub tones at -30db, my sub is 100 watts)


Caution,

For some subs the 12o clock position isn't always the right choice when calibrating...
I've had similar results with audyssey the first time. leaving the sub at -30
I've adjusted the sub level to the 10-11o clock position and audyssey calibrated the sub to -3db now.
Sound great and controlled now :thumbup:
It all blends in now without sub location troubles


I'll put it another way:
my subwoofer is rated 100 watts MAX/peak, but it could be wrong.
i'm worried about the mccac "blowing out/overpowering" my sub when it produces those tones, if i set it to the 12o clock position.
Author:  kris [ 23 Nov 2013, 13:13 ]
Post subject:  Re: Official Subwoofer thread
Did you try Setting the subwoofer knob at the 9 O clock position? start from there....
The Autocalibration should detect this and set your lfe level at the right level.
Youy can always try to increase the actuall subwoofer level starting from the 9 o clock position.
I have done it this way leaving me with the right subwoofer level blending in with my main speakers.
Crancking the volume on the sub isn't always the right choice.
You won't blow the sub if you don't cranck the level on the sub too high!
Author:  elieb [ 27 Nov 2013, 00:09 ]
Post subject:  Re: Official Subwoofer thread
kris wrote:
Did you try Setting the subwoofer knob at the 9 O clock position? start from there....
The Autocalibration should detect this and set your lfe level at the right level.
Youy can always try to increase the actuall subwoofer level startring from the 9 o clock position.
I have done it this way leaving me with the right subwoofer level blending in with my main speakers.
Crancking the volume on the sub isn't always the right choice.
You won't blow the sub if you don't cranck the level on the sub too high!


I'll try it at the 9o clock setting when it arrives, est 7 days.
thanks for the advice.
Author:  alien [ 03 Dec 2013, 03:51 ]
Post subject:  Re: Official Subwoofer thread
substance wrote:
most subs have auto turn on/off. they shut off when there is no signal coming for few minutes and turn on immediately a signal is detected. some movies they go silent for 10-15mins and when action kicks in you hear that pop sound which means your sub just turned itself on.


jdeavs wrote:
It might be that the sub is on an auto on/off setting, and there's enough time between low-freq information that the sub goes into a standby mode, then you hear it click on to full power with the low sounds starting back up. If it happens along with ongoing sounds, you might have loose debris coming in contact with the cone (could also be wiring or a tie-wrap bundled around wiring), or a damaged or mis-aligned voice coil on the driver itself. More details or an audio recording could help.



invenio wrote:
Doesn't sound right to me. How loud are you playing the sub, if the cone has detached from the housing it can make a "rattle" noise. How old is the sub, this can happen with older subs where the adhesive starts to crack around the cone. As substance pointed out, you can get a "thud" with the sub turning on but it should only happen when you first start playing something and then if you have a very long extended period of no signal (the sub then turns off). This should only happen at the beginning of a listening session and not again. Try turning off the "auto off/on" and see if it happens. If it still does, then it's not the "auto off/on" function.

Let us know what's happening.

Guys I tried turning down the volume knob on the back of the actual subwoofer itself and to compensate I turned up the volume for the sub via the internal settings on my receiver. I've found that it does slightly improve things, by that I mean the clicking sounds are both even quieter and are less frequent, but they still do pop up from time to time. With that said I think I can live with it the way it is now.

On a similar topic, I just today noticed that the back of my subwoofer has a switch that is called "Phase". It can be selected on 0 or 180. Its always been left on 0 since obviously I only discovered the switch today. Anyway should I be setting this "Phase" feature to 180? or should I leave it as its always been which is on 0?
Author:  invenio [ 09 Dec 2013, 19:39 ]
Post subject:  Re: Official Subwoofer thread
Generally you should keep the phase at 0, but you can try 180 and see if it sounds better. You want the subwoofer to be in phase with the rest of the speakers so generally most people will not be phase reversing their sub to be out of phase with their speakers.
Author:  jdeavs [ 10 Dec 2013, 02:37 ]
Post subject:  Re: Official Subwoofer thread
invenio wrote:
Generally you should keep the phase at 0, but you can try 180 and see if it sounds better. You want the subwoofer to be in phase with the rest of the speakers so generally most people will not be phase reversing their sub to be out of phase with their speakers.


Unless their speakers are vintage JBLs, which are reversed in phase from most other speakers.

je
Author:  laserbite34 [ 12 Dec 2013, 16:02 ]
Post subject:  Re: Official Subwoofer thread
jdeavs wrote:
invenio wrote:
Generally you should keep the phase at 0, but you can try 180 and see if it sounds better. You want the subwoofer to be in phase with the rest of the speakers so generally most people will not be phase reversing their sub to be out of phase with their speakers.


Unless their speakers are vintage JBLs, which are reversed in phase from most other speakers.

je


Place a small battery 1.5v on the terminal inputs and watch for a forward cone motion. if it goes in the opposite direction then you know you need to reverse the + -.
Author:  jdeavs [ 19 Dec 2013, 05:02 ]
Post subject:  Re: Official Subwoofer thread
laserbite34 wrote:
jdeavs wrote:
invenio wrote:
Generally you should keep the phase at 0, but you can try 180 and see if it sounds better. You want the subwoofer to be in phase with the rest of the speakers so generally most people will not be phase reversing their sub to be out of phase with their speakers.


Unless their speakers are vintage JBLs, which are reversed in phase from most other speakers.

je


Place a small battery 1.5v on the terminal inputs and watch for a forward cone motion. if it goes in the opposite direction then you know you need to reverse the + -.


...or the phase response of your sub.

je
Author:  laserbite34 [ 28 Dec 2013, 07:16 ]
Post subject:  Re: Official Subwoofer thread
Given I had spent a bit more on the same calibrating microphones and preamp/s I would have one microphone for each loudspeaker in the room and in theory if all playing the same spot frequency or wideband pink noise they should all sum up on the RTA not subtract.

If one is found to be subtracting rather than multiply then check its wiring inside and out and try again.

Using 9 or 10 in my room I would be cut the time down for getting them all precisely tuned. Experimentation is what its all about. You can spend time with single microphone and moving the boom stand around from seating position to seating position.

Also when placing a microphone in each seat while playing wideband pink noise, note on the RTA if you steadily swaying the boom from left to right within each seated position you'll see it levelling out within a few peaks and dips on the RTA.

Now if you place another microphone of the same type and repeat this action until the pink noise levels out.

Playing the pink noise from matched LCR independently and swaying the boom left/right and even moving it gently forwards and backwards over each seated position.

Yes it takes some time.

Then manually EQ with 1/3 octave within a few + - db tolerance. It would never be flat even if you move a few feet forwards it changes. Its a fact that can't be changed. But getting it better than what it was before for so many seats is better than nothing.

Also putting the microphone up close to each speaker driver and checking all is within roughly the same frequency and level if one speaker shows a huge dip in some part of the spectrum the driver might have to be changed. If minor then a little EQ might be applied + or -.

If all LCRS was combined into one singular speaker it the cycling pink noise on the AVR would sound as one whole with little or no change in frequency or level or phase.

Might get some more new microphones next year. I bought second ECM8000 this year but it gave up after a week? I need small precision screwdrivers to open it up and find out what caused it fail?

Maybe its simple 10 min job with right spare parts.

I can check amp output on the THX sound system and know that all is summing up. But I need lots of microphones to do the rest of the work in half the time.
Author:  albert [ 02 Mar 2014, 02:05 ]
Post subject:  Re: Official Subwoofer thread
I use an Axiom EP500 mkII in my main system. It works well for movies and okay for music. The sub does go pretty low, though (18 hz down 2 db)). I may build a low profile TubaHT this summer to see if it will work better for music. Horn loaded speakers are supposed to have low distortion. My Acoustat 2+2 speakers are difficult to match with a sub.

In my bedroom system I use a M&K MX-70 sub. It mates well with my Tetra 406 speakers but doesn't go very low (30 hz). It does work well for music and is pretty good for the occasional movie. And there is nothing as relaxing as watching a LD on a 92" screen while lying in bed. :D
Author:  elieb [ 18 Mar 2014, 02:09 ]
Post subject:  Re: Official Subwoofer thread
tried my 100 watt sub with my new avr, no problems.
Author:  elieb [ 23 Apr 2014, 21:25 ]
Post subject:  Re: Official Subwoofer thread
does anyone know how to keep a wood door from vibrating when your subwoofer is on and the master volume is above -20db?
Author:  ffutures [ 23 Apr 2014, 21:39 ]
Post subject:  Re: Official Subwoofer thread
Just picked up one of these 50w subs second-hand, seems to work pretty well - should emphasise that the room is fairly small and I'm trying to avoid disturbing neighbours etc. so I'm using it at about half power most of the time.

http://www.gale.co.uk/sub5.html

Only problem so far is it has a big external power supply that gets somewhat warm, really don't like leaving it plugged in when I'm not using the subwoofer, so at the moment I'm only plugging it in when I want to use it.
Author:  invenio [ 27 Apr 2014, 23:30 ]
Post subject:  Re: Official Subwoofer thread
elieb wrote:
does anyone know how to keep a wood door from vibrating when your subwoofer is on and the master volume is above -20db?


If you keep the door shut, you can put some insulation tape so that when you close the door, there is physical contact around the frame. They sell this at any hardware store in roles. It's cheap, keeps the door functioning. The only downside is that when you open the door you will see the tape. The other thing you can do is to try adding weight to the door as it will be less likely to resonate.
Author:  elieb [ 27 Apr 2014, 23:34 ]
Post subject:  Re: Official Subwoofer thread
invenio wrote:
elieb wrote:
does anyone know how to keep a wood door from vibrating when your subwoofer is on and the master volume is above -20db?


If you keep the door shut, you can put some insulation tape so that when you close the door, there is physical contact around the frame. They sell this at any hardware store in roles. It's cheap, keeps the door functioning. The only downside is that when you open the door you will see the tape. The other thing you can do is to try adding weight to the door as it will be less likely to resonate.


i had one of those door stoppers, the kind that make a "BOIINNG" sound, but it came off.
tried using one of my old stereos, it reduced vibration...but is a small bother to move.

elie
Author:  invenio [ 27 Apr 2014, 23:40 ]
Post subject:  Re: Official Subwoofer thread
elieb wrote:
invenio wrote:
elieb wrote:
does anyone know how to keep a wood door from vibrating when your subwoofer is on and the master volume is above -20db?


If you keep the door shut, you can put some insulation tape so that when you close the door, there is physical contact around the frame. They sell this at any hardware store in roles. It's cheap, keeps the door functioning. The only downside is that when you open the door you will see the tape. The other thing you can do is to try adding weight to the door as it will be less likely to resonate.


i had one of those door stoppers, the kind that make a "BOIINNG" sound, but it came off.
tried using one of my old stereos, it reduced vibration...but is a small bother to move.

elie


Try the tape. It's only a few bucks for a huge role (if you don't like how it looks, you can always put it around your exterior doors and save some money on heating/cooling bills in the future). The idea is that you want to have the entire perimeter of the door be in contact with the door frame.
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