True...or False? - AVS Forum
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ranger91's Avatar ranger91 08:14 AM 12-16-2011
so i have upgraded my subs,and now i think i need a bigger amp,but my friend is saying no,i need to get a 4 volt head unit instead.

AMP- Kenwood Excelon X621
SUBS- 2 Kicker L7 Solobaric 10" DVC 2ohm in ported Kicker boxes.

Im currently putting out 305(RMS)to each sub..they will handle 600RMS each.

My current head unit is an old Kenwood(so old it wont even play mp3)

He says by going to a 4 volt H/U it will hit alot harder...right now these things barely hit..and are FAR less than the single old JBL 12 i was running...very disappointed in these considering what i spent on them.

JMII's Avatar JMII 10:45 AM 12-16-2011
Quote:
Originally Posted by ranger91 View Post

He says by going to a 4 volt H/U it will hit alot harder...right now these things barely hit..and are FAR less than the single old JBL 12 i was running...very disappointed in these considering what i spent on them.

The input voltage will not make the amp put out any more power. Sure it could make it "louder" at a lower volume setting on the radio, but in the end the max output (clipping level) will be the same. The main advantage to higher voltage output is a cleaner signal between the radio and amps.

I've got a Kicker L5 in my truck and can tell you those square subs NEED power, they are not very efficient. Was your JBL 12" in a sealed box? Maybe the Kicker's are just ported really high and you now missing the low end?
ranger91's Avatar ranger91 02:42 PM 12-16-2011
no,my JBL was in a ported box
HowardV's Avatar HowardV 05:54 PM 12-16-2011
The only reason you would want to upgrade to a 4v output head-unit is if your current head-unit is at full volume and you're not getting enough output from your amp (and your amps gains are a full output). If that's not the case, a higher voltage HU wouldn't help.

And even if that is the case, you can always buy a line driver that has the same effect of a higher-output HU.

Example of line driver.

Example 2
MrBobb's Avatar MrBobb 09:25 PM 12-16-2011
I thought the reason for a 4v preout is to overcome the inherent noise in a car environment, NOT to make it louder.
ranger91's Avatar ranger91 08:49 AM 12-17-2011
i was looking at some head units last night that are 5 and 6v out...still unclear as to what the voltage does.
ranger91's Avatar ranger91 08:52 AM 12-17-2011
"Ask" and you shall receive...

"A 4 volt pre-out will give a stronger, cleaner signal at the amplifier, with a higher signal resolution. End result is your amp won't have to boost a weak signal via the input sensitivity adjustment to get the signal in the target range for the input stage of the amplifier."
HowardV's Avatar HowardV 11:39 AM 12-17-2011
Quote:
Originally Posted by ranger91 View Post

"Ask" and you shall receive...

"A 4 volt pre-out will give a stronger, cleaner signal at the amplifier, with a higher signal resolution. End result is your amp won't have to boost a weak signal via the input sensitivity adjustment to get the signal in the target range for the input stage of the amplifier."

This sounds like bogus advertising claims to get someone to buy a new 4v or higher head unit. After all, that's the entire purpose of gain controls on an amp! They are there to match the amp to different head units with different output levels.

There are times when an amp's gain controls are turned all the way up, and the head unit's volume is turned up pretty high as well. You don't hear distortion, but think there's more room for the amp to put out more power. This is usually evident during softer songs and mainly with recordings that aren't loud. This is when you want to install a line driver or getting a head unit with a higher voltage output. If this isn't a concern right now, then a higher voltage head unit will not help you in any way.
fdiggy's Avatar fdiggy 12:45 PM 12-17-2011
When using an amp you want more output from the outs. I had a Kenwood with 5V and currently now have a unit with 2V. Sound was far and away better on the 5V. Was louder and cleaner. I am currently shopping for a new GPS BT head unit and wont buy another without at least 4V. I love the JVC i have but the sound is lacking.
bellslove4's Avatar bellslove4 06:29 PM 01-30-2012
no idea haha
Mark the Red's Avatar Mark the Red 10:06 AM 02-01-2012
Are you running those subs in stereo? If so, run them in mono mode wiring. Stereo sound is useless on sub frequencies and might cause phase cancellations.

The Excelon amps are designed for the Excelon headunits which put out a 4v signal. THere have been several complaints of needing to put the gains of the amp REAL high to achieve satisfactory output from the subs when using "other" headunits. First try boosting the gain significantly on the amp. Unless you hear a significant noise floor, I will vouch for the amp having minimal clipping at high gain as I have very opinions of the entire Excleon line of products. The Excelon series amps are outstanding and all put out rated output.

Here is a link reviewing another Excelon amp.: http://www.diymobileaudio.com/forum/...5s-review.html

However, those subs are usually terribly inefficient so you might need a bigger amp if you truly are a bass head. I've never used those subs FWIW.

If with the gain much higher you still are not satisfied, you might be better served by buying a bigger amp. Or you can get the outstanding kdc-x994 headunit for like $160 shipped on ebay so it might make sense.

But if it were me, I'd get a new good class D MONO amp. I believe that to be your problem. That amp you have (class A/B) is not really meant for subwoofers even though the wattage says it is. PLus with those subs being really inefficient, its much better to overpower them.

Here is a 1500w amp for $170 shipped. Wire those bad boys at 1ohm total mono load and bass ye will have in spades. Just make sure you set the subsonic frequency at or near the tuning frequency of those boxes. Typically most prefab boxes are between 30-35Hz. Running 1500w into those subs will definitely require subsonic protection.
http://www.sonicelectronix.com/item_...500D.html#tabs
Aaronco2's Avatar Aaronco2 09:48 AM 02-20-2012
Quote:
Originally Posted by HowardV View Post

This sounds like bogus advertising claims to get someone to buy a new 4v or higher head unit. After all, that's the entire purpose of gain controls on an amp! They are there to match the amp to different head units with different output levels.

There are times when an amp's gain controls are turned all the way up, and the head unit's volume is turned up pretty high as well. You don't hear distortion, but think there's more room for the amp to put out more power. This is usually evident during softer songs and mainly with recordings that aren't loud. This is when you want to install a line driver or getting a head unit with a higher voltage output. If this isn't a concern right now, then a higher voltage head unit will not help you in any way.

There are merits to having a 4V output versus say a 2-2.5V output. It is true that your amp is getting a larger signal from the deck, but I've had 3 decks over the past 10 years in 2 different cars. My first a kenwood (fantastic unit that got used into oblivion) had 2.5 V output. Sounded great with my subs. When it died, got a pioneer with a ton more features including more bass control. it had 5V output. Guess what, still sounded great. My new car and HU still sounds great. Its a pioneer with 3V output. Granted I have always had smaller cars. Not sure if anyone w/ an SUV has noticed a difference.

I would suggest looking up your JBL's spec sheets and redesign the box/boxes. I had my GT1000d in a box that was 2x the spec'd sealed enclosure size before, and after redesigning it, I felt that I could hear a marked improvement. Same Amplifier from before. Alpine MRD-500 (can't remember exact model # right meow)

Hopefully this hasn't muddied the waters for your decision.

PS- don't start a ported v. sealed debate. I just prefer sealed!
cubdenno's Avatar cubdenno 10:01 AM 02-20-2012
Quote:
Originally Posted by Aaronco2 View Post


PS- don't start a ported v. sealed debate. I just prefer sealed!

but where is the fun in that?

See I prefer ported.

Shall we discuss?

Just kidding. We can agree to disagree.
monibithy's Avatar monibithy 01:49 AM 03-31-2012
I think no.
Winston_Smith's Avatar Winston_Smith 06:32 AM 03-31-2012
The problem is that the amp does not have enough power to run the L7‘s.

He says he is running two 10“ 2ohm dvc subs, so he can only wire to 0.5ohm, 2ohm or 8 ohm bridged. There is no way that these subs are wired to that amp at 2ohms in stereo, you can only wire them in stereo at 1ohm and 4ohm (series and parallel). The most each sub is getting is 179 watts, which is 400 watts below RMS. I think you will find that your amp is just not powerful enough.
As for the pre-out on his h/u, you ever look at the input sensitivity on an amp? On the amp that he has the input sensitivity is 0.2V to 5V, so no matter how crap his h/u is it’s still going to drive the amp.

Get a better amp, mono block amp, wire the subs to 2 ohms.
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