Some quick questions

the_maassk · 7th May 2009, 15:38

Am finishing the ICE setup on my U-VA this weekend (at least for this stage

). Have a few quick questions to the gurus before I put everything together:

1. Sub-woofer enclosure - Am getting it fabricated for a JBL GT5-S12. The enclosure is being made in .75" MDF and is a sealed one. Someone suggested filling glasswool in the enclosure! As far as I know, glasswool is dangerous - have seen it in linings of old refrigrators. Forget glasswool - should I be filling anything in the enclosure at all?

2. Whine - The amp is Blau MK II 4-channel, the HU is the legendary Clarion DXZ 785USB. I have what is normally called the 'alternator whine' from my speakers (sounds like a turbo as I press the acclerator with the HU in standby) . I redid the grounding on the amp but the whine persists. I earlier had a Nippon HU and the installer attributed the whine to a cheap HU. But now the HU is not 'cheap' any more I suppose. What could be the possible reasons for the whine and the solutions?

3. Tuning - Out of question in my city! I've collected a lot of information on ICE tuning tips from the forums and elsewhere. Will follow them and try to tune my system myself. Any last minute tips in this direction? I am also going to set up the TA on this unit (will be using the measuring tape method I suppose).

4. Voltages in the car - Sometimes (when playing audio at loud volumes), I notice that my headlights dim just a little bit. Although not a significant problem; should I redo the grounding in the engine bay with a grounding kit or a thicker cable?

TIA!

hydrashok · 7th May 2009, 16:06

1. If you've built the enclosure to specs, filling is really not needed. But a bit of filling might make the sub sound better to you. You can use the "polyfill" used in Reliance Pillows if you don't want to use glass wool. From what I've heard, 350 to 400gms of polyfill per Sq.Ft (of enclosure) would be a nice starting point.

2. Did you also check the RCAs? Low-quality RCAs can cause whine. Running RCAs and power wires together can also introduce whine (may not always be the case with good quality RCAs, but doesn't hurt to check).

Now, this is unsubstantiated by personal experience, but I've lately been hearing of quite a few people complaining of whine while using GTA MKII Special Amps. If possible, please try substituting the amp for another one (maybe a friend's) just to check whether the whine goes away.

3. It is not that difficult to do the tuning. Just set the HU to 'flat' or 'defeat' (all boosts and cuts and EQ to off) & then set the LPF & HPF, depending on the capabilities of the speakers & sub you are running. If you have 6.5" comps/coaxials up front, you can safely HPF them at 80hz and LPF the sub at 80Hz. I think the HU will let you do this, or you can set the filters at the amp end. Once you set the filters, you can do the TA and then fine-tune.

BTW, in some HUs, using the 'flat' or 'defeat' setting first will disable the crossover controls in the HU. If this is the case with your HU, you will have to first manually turn off the boosts and cuts, EQ, loudness, etc etc. Or, you can set the HU to flat/defeat and set the filters in the amp.

Yep, you will need the measuring tape to set TA. Set the driver's seat a few inches to the front (from the position it is in when you sit in it) and measure the distances to the various speakers. If you're not sure how to enter the details into the HU,post the measurements here. There are quite a few folks using that HU here, so you will easily get help.

4. If you use good quality power wires, this problem should go away. For a GTA MKII, power wires of 8AWG should be quite enough.

All the best!

the_maassk · 7th May 2009, 16:30

The box is to specs. So will omit the filling for now.

For the whine, I suspect the RCAs (some brand called Daytona). Will see if I can find a reputed brand and use them.

For tuning; recap:

Step 1 - Setting gains
Step 2 - Setting filters on the HU
Step 3 - TA

Might as well change the Amp power cable while I am at it, instead of fiddling with grounding.

Thanks!

frankmehta · 7th May 2009, 18:27

im quite sure your RCA's are picking up noise. get them changed to respectable ones(eg: mx) and you will surely lose the whine!

7th May 2009, 15:38	#1
the_maassk BHPian Join Date: Sep 2008 Location: Vadodara/ NG7 2QP Posts: 205 Thanked: 7 Times View My Garage	Some quick questions Am finishing the ICE setup on my U-VA this weekend (at least for this stage ). Have a few quick questions to the gurus before I put everything together: 1. Sub-woofer enclosure - Am getting it fabricated for a JBL GT5-S12. The enclosure is being made in .75" MDF and is a sealed one. Someone suggested filling glasswool in the enclosure! As far as I know, glasswool is dangerous - have seen it in linings of old refrigrators. Forget glasswool - should I be filling anything in the enclosure at all? 2. Whine - The amp is Blau MK II 4-channel, the HU is the legendary Clarion DXZ 785USB. I have what is normally called the 'alternator whine' from my speakers (sounds like a turbo as I press the acclerator with the HU in standby) . I redid the grounding on the amp but the whine persists. I earlier had a Nippon HU and the installer attributed the whine to a cheap HU. But now the HU is not 'cheap' any more I suppose. What could be the possible reasons for the whine and the solutions? 3. Tuning - Out of question in my city! I've collected a lot of information on ICE tuning tips from the forums and elsewhere. Will follow them and try to tune my system myself. Any last minute tips in this direction? I am also going to set up the TA on this unit (will be using the measuring tape method I suppose). 4. Voltages in the car - Sometimes (when playing audio at loud volumes), I notice that my headlights dim just a little bit. Although not a significant problem; should I redo the grounding in the engine bay with a grounding kit or a thicker cable? TIA!
	() Thanks

7th May 2009, 16:06	#2
hydrashok Senior - BHPian Join Date: Aug 2006 Location: In my Office Posts: 2,527 Thanked: 19 Times View My Garage	1. If you've built the enclosure to specs, filling is really not needed. But a bit of filling might make the sub sound better to you. You can use the "polyfill" used in Reliance Pillows if you don't want to use glass wool. From what I've heard, 350 to 400gms of polyfill per Sq.Ft (of enclosure) would be a nice starting point. 2. Did you also check the RCAs? Low-quality RCAs can cause whine. Running RCAs and power wires together can also introduce whine (may not always be the case with good quality RCAs, but doesn't hurt to check). Now, this is unsubstantiated by personal experience, but I've lately been hearing of quite a few people complaining of whine while using GTA MKII Special Amps. If possible, please try substituting the amp for another one (maybe a friend's) just to check whether the whine goes away. 3. It is not that difficult to do the tuning. Just set the HU to 'flat' or 'defeat' (all boosts and cuts and EQ to off) & then set the LPF & HPF, depending on the capabilities of the speakers & sub you are running. If you have 6.5" comps/coaxials up front, you can safely HPF them at 80hz and LPF the sub at 80Hz. I think the HU will let you do this, or you can set the filters at the amp end. Once you set the filters, you can do the TA and then fine-tune. BTW, in some HUs, using the 'flat' or 'defeat' setting first will disable the crossover controls in the HU. If this is the case with your HU, you will have to first manually turn off the boosts and cuts, EQ, loudness, etc etc. Or, you can set the HU to flat/defeat and set the filters in the amp. Yep, you will need the measuring tape to set TA. Set the driver's seat a few inches to the front (from the position it is in when you sit in it) and measure the distances to the various speakers. If you're not sure how to enter the details into the HU,post the measurements here. There are quite a few folks using that HU here, so you will easily get help. 4. If you use good quality power wires, this problem should go away. For a GTA MKII, power wires of 8AWG should be quite enough. All the best!
	() Thanks

7th May 2009, 16:30	#3
the_maassk BHPian Join Date: Sep 2008 Location: Vadodara/ NG7 2QP Posts: 205 Thanked: 7 Times View My Garage	The box is to specs. So will omit the filling for now. For the whine, I suspect the RCAs (some brand called Daytona). Will see if I can find a reputed brand and use them. For tuning; recap: Step 1 - Setting gains Step 2 - Setting filters on the HU Step 3 - TA Might as well change the Amp power cable while I am at it, instead of fiddling with grounding. Thanks!
	() Thanks

7th May 2009, 18:27	#4
frankmehta Senior - BHPian Join Date: Mar 2006 Location: Mumbai Posts: 4,029 Thanked: 3,668 Times View My Garage	im quite sure your RCA's are picking up noise. get them changed to respectable ones(eg: mx) and you will surely lose the whine!
	() Thanks