[zoiks_guy]

Dear friends,

I have a very basic question regarding the need of an amp at volumes levels low to medium.

A little bit about my setup and where I am coming from. I have Stock Verna fluidic HU, stock speakers, Kenwood 4 ch amp (will have to check the model) and JBL sub in a vented box. Input to amp goes through a High-low converter fetched from rear speakers. I noticed that Verna has front components as stock so I was thinking of powering them using the 2 free channels of my amp. This brought me to the doubt I am asking.

I understand that usually HUs pump out about 15WPC. I also noticed that car speakers are quite sensitive, with average being 93dB. Ideally, such speakers should sound quite loud if fed directly through a head unit. This brings us to the question of needing an amp for speakers (not sub). What is it that adding an amp really helps in improving the sound? If it is merely being able to pump out more watts, then can we say that for one to notice the difference between SQ with or without amp, one HAS to listen at medium to high volume levels? After all, only at such volume levels the amp would be pumping out more than 15WPC, no?

BDW, I am open towards upgrading the front speakers but considering that the stock speakers are also components, would that make a considerable difference?

[greenhorn]

Originally Posted by saurabh2711

Hello ICE Gurus,

Request your inputs on a radical idea going through my head off late.


Pardon my ignorance and lack of knowledge, and don't start bashing me..
please treat me a new-nooby or an infant in terms of ICE.

Thanks in advance
Saurabh

Bad news for you - if you want decent bass, in my opinion you need a sub. Especially if you are running a sony HU which is known to have a rather puny output (there is a reason safaris used to come with alpine). I recall fitting a 10" sub in jkdas' safari and after maxing out the settings, the bass was just about ok. If you want disco level bass, you will have to spend a lot more money.
My suggestion, get a boxed sub. should give the best results. or as a cheaper & jugaad alternative, you can try the an amplifier with a low pass input and driving the hifi speakers you have. I don't have much faith in those speakers though.

Hooking up anything in parallel with the JBL speakers is a bad idea, because the JBL speakers are already low impedance, and if you add any more load, it might be the end of the poor HU

[greenhorn]

Originally Posted by zoiks_guy

Dear friends,

I understand that usually HUs pump out about 15WPC. I also noticed that car speakers are quite sensitive, with average being 93dB. Ideally, such speakers should sound quite loud if fed directly through a head unit. This brings us to the question of needing an amp for speakers (not sub). What is it that adding an amp really helps in improving the sound? If it is merely being able to pump out more watts, then can we say that for one to notice the difference between SQ with or without amp, one HAS to listen at medium to high volume levels? After all, only at such volume levels the amp would be pumping out more than 15WPC, no?

usually only entry level comps are highly sensitive (92dBish). as you go up any manufacturer's price range, you'll see the sensitivity drop to somewhere in between 85-89). So yes, adding an amp and a higher priced set of speakers may not give you better volumes. But the improvement usually lies in the frequency response which should improve. alternately you can buy something from the SPL range of a manufacturer if you are looking at higher volume levels (most higher end speakers fit into the SPL (Sound pressure level) and SQ ( Sound Quality) focus buckets)

If you want to drive the stock comps off the amp, I have my doubts about its power handling capacity.
will a replacement comp set be better than your stock comps - that's a subjective question!

[zoiks_guy]

Originally Posted by greenhorn

So yes, adding an amp and a higher priced set of speakers may not give you better volumes. But the improvement usually lies in the frequency response which should improve. alternately you can buy something from the SPL range of a manufacturer if you are looking at higher volume levels (most higher end speakers fit into the SPL (Sound pressure level) and SQ ( Sound Quality) focus buckets)

GreenHorn, looks like I could not express myself properly. I am not looking to have higher volume levels. As I said, I listen at low-medium volumes. Let me rephrase the question. Assuming I buy a fairly efficient set of Components (93dB) in about 10K range, would driving them through an amp make a considerable difference especially considering I DO NOT like to listen at high volume levels? In other words, since the volume would be moderate won't the amp end up pumping the same power level that my HU already pumps?

[greenhorn]

apart from higher capacity, a good set of comps should extend & refine the frequency response at both extremes compared to most stock speakers (though the improvement is incremental)

What do you feel is missing with your current setup?
Highs (you feel the highs lack refinement) -> comps with a better tweeter, or just a better tweeter
Lows ( there is insufficient bass ) -> have you tweaked your bass settings in the HU?

If yes, and the bass is still not sufficient, look for a sub OR if you want the space in the boot, amp + upgraded comps, though bass would still not be the same league as a standalone sub.

My setup is running the main speakers on the HU, with a sub + amp taking care of the lows. HU + speakers alone was bearable with a bit of tweaking the loudness & bass controls etc, but the sub helps a lot. But still there is the problem of the bass coming from the back. If i lower the HPF, and route more bass to the fronts, they start distorting.

[zoiks_guy]

Originally Posted by greenhorn

apart from higher capacity, a good set of comps should extend & refine the frequency response at both extremes compared to most stock speakers (though the improvement is incremental)

What do you feel is missing with your current setup?
Highs (you feel the highs lack refinement) -> comps with a better tweeter, or just a better tweeter
Lows ( there is insufficient bass ) -> have you tweaked your bass settings in the HU?

If yes, and the bass is still not sufficient, look for a sub OR if you want the space in the boot, amp + upgraded comps, though bass would still not be the same league as a standalone sub.

My setup is running the main speakers on the HU, with a sub + amp taking care of the lows. HU + speakers alone was bearable with a bit of tweaking the loudness & bass controls etc, but the sub helps a lot. But still there is the problem of the bass coming from the back. If i lower the HPF, and route more bass to the fronts, they start distorting.

Thanks Greenhorn, I get the point. My current setup is: Stock HU with stock speakers. I know that front stock speakers are comps. Additionally, I have a 4 ch powering my sub with 2 Chs free.

What I find lacking in my setup is:

1. Unclear highs
2. Non existent bass from the Comps or rear speakers
3. Overpowered bass from the sub. Additionally, the bass is sort of delayed and lasts longer than it should. Since my sub box is vented, I am thinking of moving it in a sealed box. Is that a good idea? Note that the sub is in the boot witih parcel tray metal UNCUT.
4. My free two channels on my amp are poking me

[greenhorn]

Unclear highs -> can be a bottleneck with either the HU or the tweeters in your stock comps
Non existent bass from comps + overpowered bass from sub ->
1. no need to move it into a sealed. stuff your vent very tightly using towels etc, that should help.
2. Try swapping phase of sub
3. Disable any bass boost etc in the HU & use the gain on the amp
4. Try playing around the HPF/LPF in your HU (if any settings exist) or in your amp. Reduce the crossover frequency in your amp if it can be adjusted ( to something around 70-80 Hz)

[zoiks_guy]

Dear friends,

I have a 4 ch Kenwood KAC M846 amp. I am using two channels in bridged mode to feed my sub and two are free. It is giving me a very low quality bass and my goal is to improve it.

Since my HU is stock, I am feeding my amp using a local high-low converter (pic attached). There are two variable knobs to adjust the "level". Since there are no voltages marked on it, I am not sure how to figure out the optimum level. I would appreciate any help with the same.

[greenhorn]

this convertor might be one of the reasons for your poor bass. also which sub are you using?

Your amp supports direct speaker level input, why not get one of those harnesses
http://www.ebay.com/itm/5-Pin-Speake...MAAOSwVFlUDl7f

setting levels here, since there are no specs here is more or less by ear. The channels should be matched, and there should be no noise or distortion. Noise = low convertor level & high amp level. Distortion happens when the reverse is done.
the middle ground somewhere in between should be fine.

[zoiks_guy]

Originally Posted by greenhorn

this convertor might be one of the reasons for your poor bass. also which sub are you using?

Your amp supports direct speaker level input, why not get one of those harnesses
http://www.ebay.com/itm/5-Pin-Speake...MAAOSwVFlUDl7f

setting levels here, since there are no specs here is more or less by ear. The channels should be matched, and there should be no noise or distortion. Noise = low convertor level & high amp level. Distortion happens when the reverse is done.
the middle ground somewhere in between should be fine.

Thanks again Greenhorn. I took a lot of inputs from you yesterday and thought of revisiting each and every point in the signal path. I particularly liked the stuffing suggestion to convert vented box to sealed. Don't know why it never occurred to me .

The only reason I am using High-Low converter is that I couldn't source the harness you mentioned. I enquired at about 10 accessories shops in Navi Mumbai but in vain. Didn't want to test my soldering skills either. I will be more than happy if I can somehow source it as I am thinking of using the free two channels on the amp to power a new pair of front Comps.

Coming back to the Bass, here are the immediate steps I intend to do:

1. Figure out the max volume my HU can deliver clean power at, using the two test tones.
2. Trust my ears to figure out optimum "level" on the LC. Will use your pointers regarding noise and distortion.
3. Figure out the optimum level of gain on my amp.
4. Move my sub to A-Ch of the amp as only A-Ch supports LPF. Right now it is on B-Ch, which only supports HPF. Then switch on the LPF on the amp.
5. Check Sub phase.

1,2 and 3 could be difficult, given the variables at different stages but looking forward to it.

[zoiks_guy]

Originally Posted by greenhorn

this convertor might be one of the reasons for your poor bass. also which sub are you using?

Your amp supports direct speaker level input, why not get one of those harnesses
http://www.ebay.com/itm/5-Pin-Speake...MAAOSwVFlUDl7f

setting levels here, since there are no specs here is more or less by ear. The channels should be matched, and there should be no noise or distortion. Noise = low convertor level & high amp level. Distortion happens when the reverse is done.
the middle ground somewhere in between should be fine.

I forgot to answer your question. The sub is JBL, pretty basic one. It says 1000W (Peak). I think it is GTO series.

P.S. Sorry for back to back posts. I tried editing my earlier post but couldn't.

[greenhorn]

Originally Posted by zoiks_guy

Coming back to the Bass, here are the immediate steps I intend to do:

1. Figure out the max volume my HU can deliver clean power at, using the two test tones.
2. Trust my ears to figure out optimum "level" on the LC. Will use your pointers regarding noise and distortion.
3. Figure out the optimum level of gain on my amp.
4. Move my sub to A-Ch of the amp as only A-Ch supports LPF. Right now it is on B-Ch, which only supports HPF. Then switch on the LPF on the amp.
5. Check Sub phase.

1,2 and 3 could be difficult, given the variables at different stages but looking forward to it.

1 would be better done using some typical songs you listen to. Look for stuff with deep bass, some with fast bass, and some older stuff with purely vocals - baritone male & female
2 &3 - set both amp and the convertor at around 70%. move your HU volume controls from 0 to maximum listening levels. Adjust the amp level and then the HU level, or the convertor, depending on if you get any noise/hum

[zoiks_guy]

My 4 Ch amp powers my sub in bridged mode, with two channels being free. I just noticed that the High-Low converter I am using to feed my amp is giving out only one channel to the amp even though two pairs of speaker level inputs are physically connected. Most likely the problem is at one of points where the installer tapped the rear speakers.

I would like to ask what impact does it really have? I personally think it won't have much impact as my amp just powers a sub in bridged mode. Bigger question is, how does the amp itself picks the input signal in bridged mode? Does it pick one out of Left and Right or does it combine the two to make a combined input?

[greenhorn]

impact is not much - usually bass in music is split evenly between channels, and you would have only a 3dB loss if one channel is not playing. Exceptions are where the bass actually moved between channels - some demo ish music perhaps

the amp sums both channels to use - It's a fairly simple circuit.

Get the wiring fixed!

[zoiks_guy]

OK, facing another weird problem. When I switch on my HU and start listening at low volume, I don't hear the sub at all. I have to crank the volume up considerably before the sub starts sounding. After that I continue to hear the sub even at low volumes. Any idea what is it that suddenly makes my sub kick?