Go Back   Team-BHP > Under the Hood > In-Car Entertainment


Reply
 
Thread Tools Search this Thread
Old 7th October 2007, 16:07   #31
BHPian
 
Gill's Avatar
 
Join Date: Aug 2007
Location: Mohali
Posts: 699
Thanked: 12 Times
Default

Quote:
Originally Posted by low_bass_makker View Post
I dont understand what you two guys trying to say. The Sub is bottoming out, But why ? how come what is the problem.
Bai ji we are trying to figure out the problem too.....May be the enc is not right or the enc is too big for that sub to handle at that power!!!
SS if the sub is coming back at a slow speed then it is a good sealed box. Like I said a very small leak will work but one can check for any major leak but playing the sub only and see that any air is coming out or not.
LBM Bai ji, I read somewhere and i mentioned it in earlier post that if sub in comming out slow then there is a leak!!Hold on i will give u the link too

Last edited by Gill : 7th October 2007 at 16:16.
Gill is offline   Reply With Quote
Old 7th October 2007, 22:23   #32
BHPian
 
kURETI's Avatar
 
Join Date: Apr 2006
Location: Bangalore
Posts: 104
Thanked: 0 Times
Default

1st the enclosure needs to be airtight if its an sealed enclosure. before u check for airleaks check the dimension as per the specification of the sub. Yes using screws are better as they dont loosen when the sub is playing.
forget to check airleaks, put it on and test if the bass is tight else check for dimension or build an other enclosure with proper care.
kURETI is offline   Reply With Quote
Old 7th October 2007, 22:29   #33
BHPian
 
kURETI's Avatar
 
Join Date: Apr 2006
Location: Bangalore
Posts: 104
Thanked: 0 Times
Default

performance of the sub calls for a good amplifier and a good enclosure - selection of enclosures largely depends upon the vehicle and the amplifier.
a good and a knowledgeable installer will be of a great help to decide the sub, enclosure and amplifier.

Remember the more u spend the better you get.
kURETI is offline   Reply With Quote
Old 8th October 2007, 07:53   #34
BHPian
 
ScarySkulls's Avatar
 
Join Date: Mar 2004
Location: Halifax, N.S.
Posts: 623
Thanked: 19 Times
Default

Quote:
Originally Posted by kURETI View Post
before u check for airleaks check the dimension as per the specification of the sub.
Yep. Done. Dimensions ok. Angle of the rear slant also ok.


Quote:
Originally Posted by kURETI View Post
forget to check airleaks, put it on and test if the bass is tight else check for dimension or build an other enclosure with proper care.
Dont know what is the best way to check for air leaks except ripping out the carpet and then checking.

I think time is ripe for building another one.
ScarySkulls is offline   Reply With Quote
Old 8th October 2007, 09:38   #35
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,509
Thanked: 3,885 Times
Default

Quote:
Originally Posted by ScarySkulls View Post
I tried with all my might. Got all dimensions perfect. Sealed up the insides with a mix of the dust and fevicol. Then topped it with silicone sealant. Still leak in the end
what is the problem you are facing? bass is not tight? can you detail the sound?
navin is offline   Reply With Quote
Old 8th October 2007, 10:22   #36
BHPian
 
ScarySkulls's Avatar
 
Join Date: Mar 2004
Location: Halifax, N.S.
Posts: 623
Thanked: 19 Times
Default

Problem faced is that Sub bottoms out very easily even at moderate settings.

Read up on internet and found that a leaky box can do that. A friend also told be his incident when a leaky box was causing his IDQ's to bottom out easily.
Box changed and everything back to normal.

Why, Even our SPL Guru LBM's subs will bottom out if he tries to cover ports with hands. Which shouldnt happen because in a sealed enclosure, the Sub will effectively handle more power than a ported one. But a hand cannot achieve a good seal. Hence leak. And Hence Bottoming out.

What's your take Navin Ji?
ScarySkulls is offline   Reply With Quote
Old 8th October 2007, 11:01   #37
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,509
Thanked: 3,885 Times
Default

Quote:
Originally Posted by ScarySkulls View Post
Why, Even our SPL Guru LBM's subs will bottom out if he tries to cover ports with hands. Which shouldnt happen because in a sealed enclosure
no covering the port with hands is not a good way to seal a box.
ask LBM to try this. stuff about 0.5lb of polyfill or even opencell foam in the port (make sure it can be removed) and see if this sub stil bottoms out. what you guys are doing is tuning the box to a very low freq and the sub acoustically decouples when driven at that freq. and bottoms out.

if your HU had a Subsonic filter you could engage that and the sub would not bottom out as easily.
navin is offline   Reply With Quote
Old 8th October 2007, 11:10   #38
Senior - BHPian
 
Join Date: Mar 2006
Location: Faridabad
Posts: 6,814
Thanked: 294 Times
Default

Quote:
Originally Posted by ScarySkulls View Post
Why, Even our SPL Guru LBM's subs will bottom out if he tries to cover ports with hands. Which shouldnt happen because in a sealed enclosure, the Sub will effectively handle more power than a ported one. But a hand cannot achieve a good seal. Hence leak. And Hence Bottoming out.

What's your take Navin Ji?

As we are talk here a new enclousre of 15 x 15 x 12.5 inch is being made. The internal volume comes to 1.16 cuft. And after removing the woofer displacement volume which is 0.12 cuft the final volume is 1.04 cuft.

The enclosure volume is taken 1 cuft because more power handling is required as 1200 watts rms is going in to the sub.

I will try to run the sub with 1200 and 335 watts from the Steg and 700 watts rms with the alpine mrd-1005. So that I will get a fair idea how the sub handle different wattages...

Will be posting some details about the test tomorrow.
low_bass_makker is offline   Reply With Quote
Old 8th October 2007, 11:20   #39
Senior - BHPian
 
DerAlte's Avatar
 
Join Date: Mar 2007
Location: Bangalore
Posts: 8,076
Thanked: 2,876 Times
Default

Quote:
Originally Posted by navin View Post
what is the problem you are facing? bass is not tight? can you detail the sound?
Quote:
Originally Posted by ScarySkulls View Post
Problem faced is that Sub bottoms out very easily even at moderate settings.

Read up on internet and found that a leaky box can do that. A friend also told be his incident when a leaky box was causing his IDQ's to bottom out easily.
Box changed and everything back to normal.

Why, Even our SPL Guru LBM's subs will bottom out if he tries to cover ports with hands. Which shouldnt happen because in a sealed enclosure, the Sub will effectively handle more power than a ported one. But a hand cannot achieve a good seal. Hence leak. And Hence Bottoming out.

What's your take Navin Ji?
Aaargh! Too many assumptions, too many conjectures, too many ideas in the expression ...
* @scaryskulls has not described the symptoms that make him infer that the sub is bottoming out, since he couldn't have actually measured the travel, nor has he described he circumstances under which it happens
* That there is a leak is a conjecture
* That the circumstances of whoever said "bottoming=leak" are comparable to this situation is also conjecture
* It is possible for the sub to bottom out in a perfectly sealed box. After all, the air behind the sub is not solid, incompressible medium that will prevent the cone from traveling any further. It will at most only try to slow it down
* The bottoming out can be caused by
- the nature of the signal (independent of box) - faster the acceleration of the cone, more the chances that it will bottom out
- the amp is 'too good' or 'too bad' for the sub: too large output di/dt (no reflection on the ID sub) or too much peak clipping/ringing
* The leak, if at all, is more likely to be between the sub frame and the box, if the gasket is not seated well
* If the box is much larger than idea Vb, it could possibly lead to bottoming out under some circumstances
* Comparing sealed box behavior with ported/BR box behavior (with port closed by hand) is not correct - the internal volumes and dynamics are different
DerAlte is offline   Reply With Quote
Old 8th October 2007, 13:20   #40
BHPian
 
ScarySkulls's Avatar
 
Join Date: Mar 2004
Location: Halifax, N.S.
Posts: 623
Thanked: 19 Times
Default

Quote:
Originally Posted by DerAlte View Post
* @scaryskulls has not described the symptoms that make him infer that the sub is bottoming out, since he couldn't have actually measured the travel, nor has he described he circumstances under which it happens
Symptoms:- Bottoming out at a volume level prior to when the HU starts clipping. Bottoming out with Zero bass boosts or EQ.

Quote:
Originally Posted by DerAlte View Post
* That there is a leak is a conjecture
That is true.

Quote:
Originally Posted by DerAlte View Post
* That the circumstances of whoever said "bottoming=leak" are comparable to this situation is also conjecture
Cant understand why. Please educate more on this.

Quote:
Originally Posted by DerAlte View Post
* The bottoming out can be caused by
- the nature of the signal (independent of box) - faster the acceleration of the cone, more the chances that it will bottom out
Happens on all varieties of songs. Mp3 or Audio cd. Signal from Amp appears clean too --> Components play clean all the way.

Quote:
Originally Posted by DerAlte View Post
- the amp is 'too good' or 'too bad' for the sub: too large output di/dt (no reflection on the ID sub) or too much peak clipping/ringing
I dont think a GTO75.4 amp should be either of the two for a 10" ID sub.

Quote:
Originally Posted by DerAlte View Post
* The leak, if at all, is more likely to be between the sub frame and the box, if the gasket is not seated well
Very much possible. Best way to detect and correct leaks caused by this?

Quote:
Originally Posted by DerAlte View Post
* If the box is much larger than idea Vb, it could possibly lead to bottoming out under some circumstances
Box has been built to exact specs as on the recommended enclosure sheet.

Quote:
Originally Posted by DerAlte View Post
* Comparing sealed box behavior with ported/BR box behavior (with port closed by hand) is not correct - the internal volumes and dynamics are different
Yes, Yes. Ofcourse. That is what many others think also
ScarySkulls is offline   Reply With Quote
Old 9th October 2007, 09:52   #41
Senior - BHPian
 
DerAlte's Avatar
 
Join Date: Mar 2007
Location: Bangalore
Posts: 8,076
Thanked: 2,876 Times
Default

Quote:
Originally Posted by ScarySkulls View Post
Symptoms:- Bottoming out at a volume level prior to when the HU starts clipping. Bottoming out with Zero bass boosts or EQ.
What makes you infer it is "bottoming out"?

Quote:
Originally Posted by ScarySkulls View Post
Cant understand why. Please educate more on this.
It is a conjecture since it is not established that bottoming out, if so in your case, is due to a leak

Quote:
Originally Posted by ScarySkulls View Post
Happens on all varieties of songs. Mp3 or Audio cd. Signal from Amp appears clean too --> Components play clean all the way
Mechanics of the components are not comparable to the sub at all. In fact the root cause of bottoming out (excessive travel) is at frequencies (< 40Hz) that the components don't handle.

Try playing "Jaane kyun log pyaar karte hain" from that Aamir Khan movie - it has a synthetic bass accompaniment which slides really really low on every note. You can figure out at what point (even at low volume) the cone really starts to reach limits of excursion.

Quote:
Originally Posted by ScarySkulls View Post
I dont think a GTO75.4 amp should be either of the two for a 10" ID sub.
I agree, though I have not personally experienced the combination.

Quote:
Originally Posted by ScarySkulls View Post
Very much possible. Best way to detect and correct leaks caused by this?
Talcum, or any other, powder sprinkled around the periphery of the frame. Will not be affected by the normal bass but will be blown away by a leak! The leak should go away if you unmount and mount the sub again - make sure that you tighten diametrically opposite screws / bolts. If it still doesn't use a thin layer of either a silicone sealant or a gasket sealant used in automobiles.

Quote:
Originally Posted by navin View Post
ask LBM to try this. stuff about 0.5lb of polyfill or even opencell foam in the port (make sure it can be removed) and see if this sub stil bottoms out. what you guys are doing is tuning the box to a very low freq and the sub acoustically decouples when driven at that freq. and bottoms out.

if your HU had a Subsonic filter you could engage that and the sub would not bottom out as easily.
I agree, this could be the most likely cause and remedy. Or a smaller sealed box (ID is comfortable down to 0.7cft).
DerAlte is offline   Reply With Quote
Old 9th October 2007, 12:08   #42
Senior - BHPian
 
Bass&Trouble's Avatar
 
Join Date: Mar 2006
Location: Bombay
Posts: 2,744
Thanked: 71 Times
Default

Quote:
Originally Posted by DerAlte View Post
Try playing "Jaane kyun log pyaar karte hain" from that Aamir Khan movie - it has a synthetic bass accompaniment which slides really really low on every note. You can figure out at what point (even at low volume) the cone really starts to reach limits of excursion.
People who tried "Jaane kyun log pyar karte hain" also tried:

Bally Sagoo's version of Chura Liya
Karunesh - Punjab
Nitin Sawhney - Nadiya

Bass&Trouble is offline   Reply With Quote
Old 9th October 2007, 12:35   #43
Senior - BHPian
 
Join Date: Mar 2006
Location: Faridabad
Posts: 6,814
Thanked: 294 Times
Default

I would use sine waves for the same.
low_bass_makker is offline   Reply With Quote
Old 9th October 2007, 12:38   #44
Senior - BHPian
 
Bass&Trouble's Avatar
 
Join Date: Mar 2006
Location: Bombay
Posts: 2,744
Thanked: 71 Times
Default

Quote:
Originally Posted by low_bass_makker View Post
I would use sine waves for the same.
Yeah, on a 2400 W rms amp at that. At full tilt. No wonder you're in the market for a new battery.
Bass&Trouble is offline   Reply With Quote
Old 9th October 2007, 12:39   #45
BHPian
 
ScarySkulls's Avatar
 
Join Date: Mar 2004
Location: Halifax, N.S.
Posts: 623
Thanked: 19 Times
Default

Quote:
Originally Posted by DerAlte View Post
What makes you infer it is "bottoming out"?
If the general notion that "Speaker fat rahe hain yaar"....Or crossing excursion limits means bottoming out, then that's perfectly it.

Good idea on the Talcum powder. Thanks.
Lets see what happens. Give it a shot Gill.
ScarySkulls is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Spider Diesel Tuning Box VS. Pete's Tuning Box - Spider Box feedback on pg 2 Endeavour333 Modifications & Accessories 130 11th September 2017 01:24
DIY PICS : ANHC Fiberglass Subwoofer Box yashshroff In-Car Entertainment 56 25th August 2011 17:06
Active Subwoofer vs Free Air/Enclosed Subwoofer Epic In-Car Entertainment 2 2nd December 2009 10:59
Best direction to face box subwoofer in boot of car ? DRAGONLORD In-Car Entertainment 4 28th December 2007 02:31
Need help in making my subwoofer box libre sito In-Car Entertainment 6 27th August 2004 23:24


All times are GMT +5.5. The time now is 01:34.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks