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Thread: Hiss in Tower Speakers?
05-17-2012, 01:50 PM #1
Hiss in Tower Speakers?
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:
05-17-2012, 02:09 PM #2
I didn't click the link yet, but which eq do you have?2006 Supra 20 - Sold
2006 Supra 24 Gravity Games - Sold
2015 Supra SE450
05-17-2012, 02:18 PM #3
Hmmm.. It appears you have a Krypt EQ....
First - off, take the EQ out of the equation and wire the Kicker amp straight to the radio. Set the gain on the amp to get the volume you want based on the radio being at about 3/4 of max volume. Note, your head unit tone controls, (bass and treble) should be flat. With the setup this way and the radio turned down all the way do the speakers hiss?
If when the amp is wired straight to the radio there is no hiss and you can get your desired loudness, the hiss is coming from the EQ.
If when the amp is wired straight to the radio there IS hiss, the noise may be due to your perception that the tower speakers need to be louder, and you are compensating by setting the gain higher than necessary to try to get more than max power out of the amp.
At high volume do the speakers get all crunchy like your dads stock car stereo when it is turned all the way up? I ask this question somewhat gingerly, as I don't want to offend you, but I hear way too many systems where the owner has no clue that the amp is in hard clipping and the speaker cones are being bashed around so hard by the clipped square wave signal that the sound is more a buzz than music... A generation or two have grown up with no sense of what a clean non-distorted stereo sounds like; they simply don't know and think that crunchy sound of a heavily-clipped amplifier is what music is supposed to sound like when it is loud...
I have a feeling that the hiss is going to go away when you remove the EQ from the signal chain. Every piece of electronic gear you put between the CD or iPod and the speakers has a pre-amplifier gain stage, and all pre-amps make some noise. Some are worse than others, but know that the better the gear, the lower the noise generally. Your radio has a preamp stage and it makes a little noise. The EQ has a preamp gain stage, and it amplifies the little bit of noise in the radio, plus it adds its own. As you experienced with the amp, its gain stage will add noise when turned up, so that is a good example. For every part of the signal chain you want gains set as low as possible while set just high enough to give you rated power output from the amp.
Unfortunately, sometimes you find that a piece of gear is just inherently noisy, and a HLCD tower speaker is going to be very revealing of that. There is not going to be much you can do short of finding out where the noise really lives, and then either eliminate it by removing the offending piece of gear from the system, or replacing it with a product that has similar function, but better performance and signal-to-noise specs.
Last edited by philwsailz; 05-17-2012 at 02:21 PM.
05-17-2012, 02:29 PM #4
05-17-2012, 02:40 PM #5
Why do i feel worried now??89' Comp Resto:
Riding and Mod pic's:
89' Supra/Custom Tower & Interior/Swivel Racks
4 Blade-14X14/1600 lbs Ballast
Roswell Bar/Led's/Krypt 6.5 HLCD's/Krypt 4200 Eq
JL-PPI Amps 1750 Watts/Kicker Interiors/L7 Kicker Sub
05-17-2012, 03:23 PM #6
Here is a quick check. If the amplifier is run at a 4-ohm load the input gain may be set a little higher...for 2-ohm load a little lower. If the EQ has strong preout voltage this will reduce the amplifier input gain. So disconnect the RCA inputs to the amplifier and set the amplifier input gain at an anticipated 35 percent to reach full power in this scenario. When the amplifier is turned on any thermal noise you hear is totally owned by the amplifier and I would expect it to be there but minimal. Any additional noise you hear once you plug back in the input RCAs (please power down before un/plugging/in RCAs) is totally owned by the components upstream in the signal path or a mismatch in the interface between the upstream components.
05-17-2012, 05:03 PM #7
Phil, thank you for the detail, however I don't have a radio/HU. My source is my phone, which goes aux in to the EQ, then to the amps. Also, I know what you mean by not understanding what loud is supposed to sound like, but it truly wasn't loud enough.
Wolfeman, my system is an on-going project that can't be completed all at once with my budget, can't wait to get the whole thing dialed in with high-quality stuff!
David, thanks for the suggestions, I'll try that out.
05-17-2012, 05:49 PM #82004 Moomba LSV Blue
05-17-2012, 06:19 PM #9
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.
05-17-2012, 07:08 PM #10
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.