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Old 7th November 2010, 23:23   #10501
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hello!

For a budget of 10K for the first stage, what would be the best way to improve the stock ICE of the i20?

Will just better compo's for now and an amp later on help?

-Thks!
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Old 8th November 2010, 09:44   #10502
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Quote:
Originally Posted by abhipuru16 View Post
Guys!
I just completed with tuning my amplifier with a Digital Multi-Meter.
Everything, I think, went good "finally". I am writing a long post describing all that happened today.
The outcome is many times better as before the vocals were not being played to my liking.

First of all, the equipment-

Velocity VPA4130 Amplifier
Fiesta Stock Headunit with Pre-outs taken from the Mainboard

According to the amplifier's rating of
4X130Watts RMS at 4Ohm
2X400Watts RMS at 4Ohm

I was aiming for 23V for front channel and 40V for the rear channel.

So, I first stickered and labelled all the speaker wires to keep polarity under check.
I put the Multi-meter's + in the place where my sub's positive went and "-" likewise. The subwoofer runs bridged from the rear channels.
After that, I set the 50Hz 0db test tone on repeat and kept the volume to 75% of my headunit's maximum volume which is 34, that is, it was set at 24.
Now, while increasing the gains, their came a point where there was kind of a hilltop, after which, a further increase in the gains resulted in a decline in the voltage that the DMM showed.
When the volume was at 24 the hilltop came in at 20.xxV. Further increasing the gains resulted in a decrease in the voltage.
So, after a lot of tinkering around I frustratingly maxed the headunit's volume at 34 and then tried setting the gains. This time the maximum voltage I could achieve was 38.9V.
Now, during all this, the interesting thing I noticed was the gains were set quite low for both front and rear channel. Almost like 1/5th or 1/6th of the total.
The best part was that the gains for the front channel were set when the DMM read exactly 23V.
I am thinking, could I have further gained those 2V in the rear channels if I had set the volume to something like 30 or 32?

By the way, before proceeding with setting the gains, everything was set to a big "ZERO" both on the headunit and amp.

Is there anything wrong?

EDIT-
Also, given that I have taken pre-outs from the Head-unit's mainboard, even if I turn the volume to maximum and set the gains, would there be any distortion that could cause problems in tuning?
I don't think so because we are taking the signals well before they are fed to the Head-unit's amplifier.
Correct me if I am wrong.
No replies? Help me please.
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Old 8th November 2010, 09:46   #10503
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@spyking, if you stretch your budget a little bit, you will be able to get the following if you select judiciously to get a substantial improvement:

1. Good components in front (~6K) - anyhow required to get any improvement
2. A 4-channel amp (4.5 - 6K). But, first check if your stock HU has Pre-outs, else
3. Line Output Converter (~3K)
4. Wiring - good RCA cables + Finolex / Havell / L&T cables for power

@abhipuru16, first get used to whatever you are getting, so that you can tell the difference of any change that you would like to make in the future. Trying to extract the max out of the amp without checking what you are getting as normal output at this level will lead you nowhere. Concentrate on getting a balanced system first.

Setting the volume to max need not lead to distortion if the signal voltage in this condition does not lead to amp saturation and clipping. Did not understand the "well before" in your expression "well before they are fed to the Head-unit's amplifier". Where exactly was the signal tapped off? The only place one can / should is at the output of the pre-amp after the mixer, and this is just before the HU amp.

Last edited by DerAlte : 8th November 2010 at 09:56.
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Old 8th November 2010, 09:54   #10504
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Quote:
Originally Posted by DerAlte View Post
@spyking, if you stretch your budget a little bit, you will be able to get the following if you select judiciously to get a substantial improvement:

1. Good components in front (~6K) - anyhow required to get any improvement
2. A 4-channel amp (4.5 - 6K). But, first check if your stock HU has Pre-outs, else
3. Line Output Converter (~3K)
4. Wiring - good RCA cables + Finolex / Havell / L&T cables for power

Sir, is there any difference in using Speaker Line Inputs on the AMP and Line Out Put Convertor? Am using speaker line inputs to drive comps and thinking of to improve if there is considerable difference with the Line Output converter.
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Old 8th November 2010, 16:13   #10505
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Guru's, I need help with subwoofer enclosures. I am more interested in 0.8 cu.ft and 1 cu.ft sealed boxes. What would be the enclosure dimension interms of L x B x H for the above mentioned volumes.
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Old 8th November 2010, 16:22   #10506
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Quote:
Originally Posted by donarun View Post
Guru's, I need help with subwoofer enclosures. I am more interested in 0.8 cu.ft and 1 cu.ft sealed boxes. What would be the enclosure dimension interms of L x B x H for the above mentioned volumes.
Dimensions are not that critical but make sure of teh following.

a. The depth of the enclosure should be such that the speaker has some breathing rooom behind the magnet. 3" is enough.

b. the height and width of the baffle (the board on which the speaker is mounted) should be such that the speaker can comfortable fit on it

c. the intnernal volume of the box (Hx W x D) should be 10-20% more than the calculated volume to allow for displacement of the woofer.

d. If possible have as few NON parallel sides as possible

For example for a 1 ct. ft. box and a 10" woofer a box that is 14" x 14" x 10" should be enough but you could also have a box where the depth is 12" at the bottom and 8" at the top instead of 10" even.

Last edited by navin : 8th November 2010 at 16:23.
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Old 8th November 2010, 20:52   #10507
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Originally Posted by DerAlte View Post
@spyking, if you stretch your budget a little bit, you will be able to get the following if you select judiciously to get a substantial improvement:
The HU is a Nippon unit and does not come with pre-outs.
Would you suggest some good budget amps?
And I was suggested on the forums to look at Bull Components as they won't be to bright with the HU, what would be the models to look for?

Thanks!
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Old 9th November 2010, 17:46   #10508
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GURUS,
i have the following things in hand, collected over the past 6 months, one by one and need your advices for fitment in a hardtop MM540 jeep.
1. Blaupunkt Melbourne SD27 HU - 18W RMS x 4 channels, with Aux Line In, 4 Preouts for Amplifier and only SD Card Reader, of course with FM/AM radio functions. i like this HU bcoz of its simplicity and also my main listening would be only in SDCards, ripped from cds.
2. Kenwood KAC-M845 4 channel amp - 60W RMS x 4 or 180W RMS x 2 @4ohms
3. Blaupunkt Vc130.4 Components - 5.25" size - 40W RMS min and 150W RMS max power handling capacities
4. Blaupunkt Vx 542 Components - 130mm/5.25" size - 70W RMS min and 280W RMS max power handling.
5. PolkAudio Subwoofer - 8" - DB840 - SVC - 180W RMS min and 360W RMS peak power handling capacities.
6. Boss Audio 18 Farad Super Hybrid Capacitor, with options for connecting 2 amps at the same time.
7. Overhead Flip Down 9" LCD Monitor with DVD Player, USB/SD Slots, In-built Speakers, FM Transmitter, AV in/out, IR Headphones etc.,. This is a seperate unit which can be used for the rear passengers, who can watch the video, hear the audio in the headphones, without disturbing the front passengers - who can listen to the audio...

My doubts/clarifications needed are:
option 1:
1. as there is no sub out from the HU, so the front 2 channels can be connected to the amp, flowing to the components - if yes, which of the 2 components would match best with the amp output specs ? Vc 130.4 or Vx 542 ? pls help me to decide.
2. the rear 2 channels need to be bridged in the same amp - to drive the polk 8" sub, would that be fine as the amp is pushing out only the min rms needed for the sub ?
2 front components plus an 8" sub - all driven by the kenwood amp - am i speaking rightly ?
Option 2 :
1. the front 2 channels are divided into 4 so that 2 channels go to the Vc 130.4 Comps and the other 2 channels go to the amp, and then to the VX 542 comps - how to do this efficiently ? how to make 4 outputs from 2 channels ?
2. the sub is driven from the same amp, rear channels to the amp, bridged to drive the sub - is this correct ?

Option 3:
1. front 2 channels to the kenwood amp, then to the Vc 130.4 Comps and
2. rear 2 channels to the amp, then to the Vx 542 comps
3. if this is the case, where can i take the sub out ? what to do for this ?
4. will 4 comps be enough filling, without a sub ?

Audio Gurus, pls help me to make a blasting ICE in my jeep.
i would also like to know the speakers/subwoofer placement positions in the jeep interiors...as to where and in what direction to keep the speakers, tweeters, sub etc., in my jeep. the front seats are bucket seats and the rear are side facing seats.

Have a Safe Motoring, Cheers.
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Old 9th November 2010, 18:52   #10509
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Hi Shekaran
I recommend option 1

1. The preamps for rear could be used to send out a mono signal for the subwoofer. The HU might have settings for this.
If there are stereo->mono settings in the HU, there's a high probability that the amplifier has a slider switch that switches between stereo and mono output.
You'll have to bridge the rear channels from the amplifier and LPF the signal to the sub.

2. Use the VX542 components. Avoid running the VC130.4 off an amplifier.

3. 150 RMS should be adequate for the 8" polk sub.
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Old 9th November 2010, 20:06   #10510
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Another question friends.
If I play a 80Hz 0db test tone and put the DMM terminals to the speaker outputs from the amplifier with the HPF well above 80Hz like say 100Hz, would there be any voltage reading shown by the Multimeter?
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Old 9th November 2010, 23:18   #10511
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@abhipuru16 yes you would but down by about 50%. That's because most amps while they do not play flat have a industry standard 12db/oct filter. Unless you pick higher. Basic theory says for every octave moved down it would be 12db reduction.
Out of interest To understand this you will have to read up on octave progression in say a piano. that will help in the correlation to frequency. Then apply it to the volume reduction.
*BUT* remember the pots(rotary controllers) on the amp are not linear but log. For more details on that see amp manual or wait till navin sir replies. He knows it *much* better.
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Old 10th November 2010, 00:06   #10512
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Gurus,
As Nitrous Suggested, am planning to setup my ICE as the pic attached.

1. front Vc 130.4 Compos run off the HU front 2 channels pushing out 18W.
2. rear Vx 542 compos are driven by the kenwood amp pushing 60W x 2 channels.
3. polk 8" sub is driven by the bridged 2 channel output of 180W from the amp.
the capacitor is connected between the battery and the amp.

what are all the cables i need to use for the above connections ? friends, pls specify make, availability in chennai and also the approx. price. how many fuses i need to use, placement ? what type of rca cable for hu to amp connection ? what will be the best speaker cables from the amp to the speakers ? what will be the power cables specs ? what more parts/wires should i include ?

Gurus, pls suggest in what direction and place, all these speakers/tweeters/sub shoulb be placed for a rich sound effect, inside the boxy jeep interior.

Thanks for all the suggestions, advices. Happy Motoring. Cheers.
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Old 10th November 2010, 01:09   #10513
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Quote:
Originally Posted by valhallen.282 View Post
@abhipuru16 yes you would but down by about 50%. That's because most amps while they do not play flat have a industry standard 12db/oct filter. Unless you pick higher. Basic theory says for every octave moved down it would be 12db reduction.
Out of interest To understand this you will have to read up on octave progression in say a piano. that will help in the correlation to frequency. Then apply it to the volume reduction.
*BUT* remember the pots(rotary controllers) on the amp are not linear but log. For more details on that see amp manual or wait till navin sir replies. He knows it *much* better.
Would it be an abrupt change in the reading?
Would I be able to know that I have infact reached 80Hz on HPF or for that matter LPF?
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Old 10th November 2010, 11:00   #10514
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Quote:
Originally Posted by abhipuru16 View Post
Another question friends.
If I play a 80Hz 0db test tone and put the DMM terminals to the speaker outputs from the amplifier with the HPF well above 80Hz like say 100Hz, would there be any voltage reading shown by the Multimeter?
Quote:
Originally Posted by abhipuru16 View Post
Would it be an abrupt change in the reading?
Would I be able to know that I have infact reached 80Hz on HPF or for that matter LPF?
The reading will not be abrupt. A crossover has a slope of say 12/18/24db per octave.
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Old 10th November 2010, 11:33   #10515
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So, there is no way to set HPF/LPF accurately (well, theoretically) with something like a DMM?
And by the way, my amplifier has a 12db/octave slope, it's fixed.
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