line drivers
 

Hello all,
I am experiencing a slight hiss through my inboat speakers and tower (Rev 10s). The deck I believe puts out 4V to a WS420. After doing some research I see others are having this problem also and installed a line driver between the deck and EQ and this took care of the problem along with also making the overall system sound better. I think I have narrowed it down to either the Audio Control Overdrive Plus or the Arc Audio ALD. If anyone has any imput on this I would appreciate it, I want to make the best decision and only do this once.
Thanks

I had the Arc with the old WS420 it sort of helped, upgraded to the WS 420 SQ, and hiss was 100 gone. I would ditch the 420 and get a 420SQ

I would check my RCA's first. Then check and see if your gain is too high. I only have a 2volt pre-out deck running to a clarion eq746eq 7 volt pre-amp and I have zero hiss in the speakers.

I have already checked all of that. I have also heard that people running th Clarion do not have the problem that the Wetsound has.. How do you like the Clarion as far as adjustments are concerned because that is another one of my options.

I like it a lot. For $45 you can't beat it. The only thing is I have to use the fade knob for the inboat and towers.

I have the ALD.. LOVE it!!!
I had it in front of a 420 last year.. Zero noise.
I upgraded to the SQ this year.. Still zero noise..
I agree with making sure your gains are set appropriately though.

Not sure I see the justification for a line driver if you already have a true 4 volt source unit. The line driver does a great job if you have a weak HU preout section or an ipod (which automatically has weak voltage) used directly into an EQ.

David

I also have hiss which is only in my REV 8's not in the factory JL installed cabin speakers. Using the factory MC installed JL amp to drive sub and two WS amps for boat/tower all going through the WS 420. Clarion CMD8 head unit. Is this similar to your problem?


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That sounds like the same problem, but I have it through all my speakers. The 4V pe-out is what is stated in the manual and not measured so I am not sure it is 100% accurate. I will check my gains again, but if I remember correctly they were about 35%.

What amps are you running?

You shouldn't need a line driver between you HU and EQ

Lets just say your HU only puts out a few volts. That's what the EQ is suposed to correct.
Tim says the WS420 is a Line driver so u should be good to go.

A good example of where a line driver would help you out is if you didn't have a EQ or your EQ was passive (no voltage boost) OR you wanted to push or send a signal to a buddy over a 20+ RCA cable a line driver would be the ticket.

I have the Arc line driver boosting a signal to a subwoofer I have in my Garden.
It's a 30 foot long run and by the time the sub signal got to the outdoor sub it was very week.
After I installed the Linedriver I have lots of headroom and signal.

Check your RCA's out of your HU, and if they are all good you Might want to think about testing out a new HU with a stronger signal. And if that dosen't do the trick mabey look at the EQ

If the amp question was directed to me:

2 SYN2 amps (4 JL cabin/4 Rev 8's)
1 JL M400/4 driving the JL sub

The Rev 8's hiss when powered on. Cabin speakers are quiet.

Gains on amps are below 50%, WS 420 tower level just higher than cabin, adjusted to max head unit volume setting 27.

Hiss is costant at any volume level.

The amps I am running are:

Jl HD 750/1-Jl W6
JL MHD 600-inboats/Diamond HEX 6.5 componets.
Alpine PDX 4.150 bridged to 300/2 for tower/Rev 10s

Thanks for all the help and ideas.

Two distinct issues here.
First,
So let's say that your in-boat speakers have no hiss, or at least it is minimal. In contrast, the tower speakers do have hiss that is noticable, at least when you are still and quiet. But the EQ processor is common to both zones. And, the tower amplifiers and in-boat amplifiers are essentally the same internally from a noise standpoint. Soooo, what is difference between the tower and the in-boat? The answer....An HLCD tower speaker that is at least 10 dB more efficient and therefore the equivalent of TEN TIMES the gain. And that means the 'hiss' level from the tower is bound to be greater by 10 dB....or exactly the same as if you have 10 times the amplifier power generating the noise. You can't escape the difference.
Second,
The last thing you want is a roller-coaster ride in the gain level from component to component. With weak gain anywhere in the signal path, the impetus for the gain recovery falls on the next electronic component. Yes, each component may have its own gain adjustment. But, when too much gain mutliplication falls on a single device, you are going to raise the noise floor in comparison to the music material. Or, you can too severely clamp down on the noise floor by a gain reduction and sacrifice ultimate dynamic range. There is a good balance that will limit noise but not limit the peak music reproduction. However, you can have an equipment mismatch where there is insuffient gain from one device causing you to overly compensate on the next device. And that correction can induce more hiss. There are some cases, not all cases, where a line driver can correct this. But it is not always in the same signal path location. An ipod has a very weak pre-out voltage. So in some cases the line driver benefit is best served going between the ipod and the source unit aux input (but easy does it on the gain). For example, if you have a great inequity in gain between the CD source and ipod source then you may want to add a line driver to the ipod only. In other cases the line driver would go between the source unit and EQ. In some cases with a high voltage pre-amp source unit you wouldn't want to add any more gain and you would not use an external line driver. So the location in respect to the signal path is important. The specific equipment being packaged together is important. And the physical location of the line driver is important. You want the line driver closest to its input source and prior to any long cable path.

David

Clarion head unit to ALD
ALD to 420
420 to 3 Syn 2's and 1 Syn 4
ZERO noise anywhere

Hey David,
^Not to hijack a thread but...
In the case of a HT-6, 2 channels for the bow, 2 channels for the dash speakers, and 2 channels for 4 cabin speakers, I find the dash speakers are way to loud, in comparison to all others. My question is if I turn gain right down on THE 2 CHANNELS ONLY supplying the dash speakers, would the same hold true compensating on the next amp when only 2 channels are turned right down, or are you referring to the gains on ALL channels on 1 amp being too low

If I interpret your comments correctly the direction to take is to turn down gain on rev 8 and balance desired output at 420. At a minimum, i will investigate reduced amp gain to see if the hiss can be eliminated or reduced. Thanks!


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Dave,
Your question really has nothing to do with the topic at hand so let's make a total disconnect.

Addressing your situation, the speakers atop the dash have a positional advantage and as a result an amplitude advantage. Of course you want to gain down those two speakers so that they are in balance with the other four cockpit speakers behind you. Also, there are some serious comb-filtering problems with speakers reflecting off the windshield creating an erratic response. Given that this location typically sounds strident is another reason I don't want them to dominate....just mesh with the others.
The bow is another zone and the two zones have no bearing on the other.

David

Well I ordered the ALD, if it doesn't solve the problem, I will just put it in my truck. Thanks for all of the help and I will let you know.