Hiss in Tower Speakers?

[ChrisK]

Yes it does, awesome to be a part of a forum where people drop knowledge like this.

Most of this stuff is over my head so I'm going to ask a dumb question. A lot of the time I'm playing music through Pandora and I know the app has a setting where you can increase the quality of the music but if you do it drains the battery quicker. If I have it on the poorer quality setting could that be a culprit of the hiss? Again, probably a dumb question.

Also, if I get one of these so-called line drivers, will a standard aux male-to-male cable be sufficient to carry the power? Or do I need to purchase one that is higher quality?

It is an iphone, btw, don't know if that matters.

[bbuhtz]

Just installed new Exile surf-style speakers with a Kicker ZX550.2 amp powering them. The speakers sound awesome when turned up, couldn't be happier. However, when I turn the tower speakers all the way down on my EQ, I can hear a hiss coming from them. When I turn the gain down on the amp it goes away but if I turn the gain down just to the point where I can't hear it, I then can't turn the volume up enough on the EQ enough (volume all the way up is only about where I would want half or 3/4 to be).

Any suggestions? Here's a link to some pics on the supra forum:

http://www.supraboats.com/bbs/showth...er-PINK!/page6

Sounds like it is just your tower speakers with the hiss from your discription. Do your in boats have the hiss sound as well? If its just the tower speakers I'd think you would be able to narrow it down to either the EQ, EQ and amp gains, or some wiring, either cheaper RCAs to the tower speaker amp (550 i believe). I doubt that it would be your phone if you are not experiencing the hissing coming from the other speakers (inboats). Also could try just flip flopping the RCA outs on the EQ (inboats swapped with the tower) and see if that makes a difference. See if that changes the hissing from the towers to the inboats. Good luck, I had the hissing last year just from the tower speakers but it ended up being a bad HU and you don't have one, so that rules that out.

[EarmarkMarine]

Listen to what Phil said about the line driver after the iphone and before the EQ. You can bet that EQ has hiss and is the primary culprit. 'Hiss' is a matter of a ratio between the EQ's noise floor and the music material. The iphone has very little voltage which places the impetus for increased gain mostly on the EQ. If a cleaner line driver takes most of the gain responsibility then much less is demanded of the next gain stage which is the EQ. I can definitely see how this would produce less noise.

David
Earmark Marine

[ChrisK]

Just messed with the RCA's. The hiss went away when I disconnected the two RCA's designated for the tower from the back of the EQ. So this obviously means the culprit is the EQ, correct? Would a line driver solve that problem? Would a higher quality RCA between EQ and tower amp help the problem?

Thanks again guys.

[EarmarkMarine]

The RCA cable isn't contributing to the hiss.

[ChrisK]

I know, disconnecting the RCA from the tower outs revealed that the problem is the EQ, correct?

[jmvotto]

Chris, it's not the brand of eq it just the addition of one with hlcds.i had a ws420 on the old boat and same deal. I believe the Krypt 4200 has a adjustable gain on it for the line driver input may try adjust that.

https://forum.moomba.com/showthread....highlight=hiss

[philwsailz]

I know, disconnecting the RCA from the tower outs revealed that the problem is the EQ, correct?

Ding ding... We have a winner.

Back to my last post: while I am not going to point simply to the EQ as the culprit, it might be, (Wolfe, I know what you are thinking) but bottom line, it is at best passing through the voltage from your iPhone and not providing any amplification while at the same time is contributing at least some noise at its noise floor threshold.

A basic head unit will deliver 1-2 volts out at the RCA line outputs. A high-end head unit might deliver 5 or even more. Your iPhone might be putting out a quarter-volt. There just is not enough difference between the output sound from the phone and the noise floor sound of the EQ.

With a 2x line driver you theoretically will increase the voltage from a quarter to a half volt. Still not a lot but that is 3dB. 3 dB right Dave? As a result you can lower the gain of the amp by a corresponding 3 dB and in a perfect math world means you lower the relative hiss by half.

I am really teetering on the line here, so I am trying to be as objective as possible. Kicker makes a device that essentially makes your phone a source unit and has the voltage output to keep amp gains lower than you currently set them. As a bonus, the audio comes out of the 30 pin connector, and charging goes in. When plugged in your phone won't go dead.

The device is our PXi50.2. I will stop there as any more information takes my objective statements to subjective; something I avoid. Google it or ask more questions here but know it might be a solution that will allow you to keep using your current EQ.

Hope that helps

Phil
Kicker

[philwsailz]

Most of this stuff is over my head so I'm going to ask a dumb question. A lot of the time I'm playing music through Pandora and I know the app has a setting where you can increase the quality of the music but if you do it drains the battery quicker. If I have it on the poorer quality setting could that be a culprit of the hiss? Again, probably a dumb question.

Nope. Low-Q will sound really compressed and AM-Radio-sounding but it is a difference in signal quality, (resolution) as opposed to signal amplitude, (voltage).

Phil
Kicker

[ChrisK]

Thanks for the help, still interested to hear everyone else's opinions!