Verify Amp/Speaker Wiring and Make Corrections?

I picked up 3 Electrovoice Evid 6.2's cheap, that's why I chose to use them...so now I'm curious if you guys can check this wiring to make sure it's ideal for the conditions. The only in-boat speakers I have are the 4" Fosgate coaxials and I thought it would be better to run them off the 4th channel of the Kicker amp as opposed to the head unit. If you think otherwise, let me know. I just can't seem to wrap my hands around ohm dropping and bridging and all that good stuff. Although the Evids are 8 ohm, somebody who used to own them said he just hooked them straight up to the amp (same Kicker listed) and it worked fine. I wired the dual voice coils on the sub per the JL Audio website. All suggestions and comments welcome. Thanks. (and if you're wondering why I'm using some of the stuff I'm using, it's because I found it all cheap and I was on a budget...sort of)

This note is from the owners manual of the Evids, not sure if it helps: The crossover frequency is set for the ideal 160 Hz acoustic crossover point with a 4-ohm load on each satellite output. It is best to use a 4-ohm load on each satellite output when possible. Increasing the impedance of the satellites on a satellite outputs lowers the crossover frequency to the satellites, resulting in more overlap between the subwoofer and the satellite. Using an 8-ohm load on each satellite output results in operating the satellite down to 80 Hz.



(Message edited by leblanc1 on May 03, 2006)

(Message edited by leblanc1 on May 03, 2006)

If I read your diagram correctly it's not correct. This will result in a 2 ohm load on one channel and a 8 ohm load on the other 3 channels. This will be a tricky one. If you wire the Fosgates in series they will look like a fourth Evid to the amp. Wire two of the Evids in parallel and the third in parallel with the pair of Fosgates. This will result in 2 x 4ohm load to the kicker's 400x2 (200w to each Evid, 100w to each Fosgate). Run L+R to bridged front, same to rear, everything will be running mono, anything else will just get weird. You won't miss the stereo once those Evids get going. I would raise the XO up to 200hz or you will probably blow the cones out of the Evids or Fosgates.

One more thing, I blew up my first amp running the evids in 8 ohms stereo, I wouldn't recommend car amps pushing 8 ohms. There endless other options.

That made sense Mike. More like this? I'm becoming cross eyed doing this.

Steve,
If you wire your Fosgate 4" speakers in that configuration (second diagram), they will not last long. The left channel will see a 4 ohm load as you have it drawn. This means that the amplifer will deliver 400W to a 4 ohm load, hence each 8 ohm on the left channel will split the 400 Watts. i.e. the Evid 6.2 on the left channel will get 200W and the Fosgate 4" speakers will get 200W (100W each). I didn't look around much to verify the specs on your kicker amp, but I believe those are RMS ratings. This is going to be a tricky wiring situation. In the second diagram, each Evid on the right channel will get about 200W so, that is probably enough power for them. The way you have the Evid's wired in the first diagram, they will only get about 50W of power each. Your diagram says that the Evid rating is 300W each, is this max power or RMS?

For your sub, is that the 12W3V2-D2 or 12W3V2-D4? If it is the dual 2 ohm voicecoil then your drawing is correct. If it is the dual 4 ohm voicecoil sub you will want to wire the voicecoil's in parallel.

Wire all three Evids in series, then bridge them to two channels on amp-resulting in 4ohm mono, then just run each fosgate to each other channel and turn the gain down to protect them from blowing. If you want to run the evids wired in parrallel then they will end up at 2ohms on the amp-here's a rule of thumb-two speakers wired in Par. will cut the ohm in half, add a third and that willcut in half, a forth and that will cut in half. OS four 8ohm speakers wired in Par will have you at 1ohm, three will have you at 2ohm. Just remember, your 4 channel amp is two amps in one, try to keep one set of speakers on one side and the other set on the other side, this will allow you optimal control of crossover frequencies and power to the speakers so you can balance the sound best!

*glad you changed your mind on the amps, definetely a better choice...

Jeff,
That is not right.
Three 8 ohm speakers in parallel will give you 2.67 ohms. The equation for parallel impedances is Z = 1/(1/Z1 + 1/Z2 + 1/Z3 ....+ 1/Zn). Where Z is the impedance of the total load, and Z1...Zn is the impedance of each speaker wired in parallel. If you wire four 8 ohm speakers in parallel you will get a 2 ohm load.

If Steve wired all three Evid's in series he would get a 24 ohm load.

Steve if want to talk about this further, feel free to PM me and we'll figure something out.

Jeff, your calculations are off, like Mike mentioned this is a very tricky setup and you will get things to work but far from optimal. if you wire those fosgates up to that amp your proabbly going burn up the voice coils pretty quick. What about wiring two evids in parallel, bridge two of the channels, then run the fosgates of the HU, and run the one evid off one of the remaining channels. Keep an eye on the amp, like Miek mentioned for some reason?? car audio amps don't like constant resistances higher than 4/6 ohms. On second thought, sell one of the evids and the fosgates you have and buy two sets of co-axials, your amps will thank you.

Right, i understand it won't be exactly 2ohms but that is essentially what you will run at, also needing an amp that is stable at 2ohm Bridged that is. I was backwards on the series thing, but there is absolutely no reason why he can't run his 4" fosgates off each of the other two channels. No voice coils are going to burn up unless you crank up the gain on your amp, but yes you can also run them to the Head unit and run the third tower speaker to your other two channels bridged. I have all my boat speakers to my radio and 4 tower speaker to my 4 channel amp, and two 12 subs to a mono amp and all is good..and loud as hell

If I run the Fosgates off the HU and the third Evid bridged to the other two channels of the amp, what power will the speaker see at 8ohms and the amp putting out 400W bridged? What negative effect does this have on the amp? To me it would seem to cut the power in half to 200W? (bridged at 400W...is that 2ohms or 4ohms?)

Steve,

What most guys don't really grasp is that whenever you run wires in series or parallel you are still splitting the power to the speakers. In series you are splitting the voltage between the speakers. In parallel you are splitting the current. Either way your speakers will see 1/2 the power delivered from the amp. I still feel that the way I would this particular combination of components is the same way I described it first. If you blow the Fosgates up then replace them, but I think they will handle the power especially if they are crossed at 150hz+. I would not run the Evid's unbalanced as shown above. I would add another amp maybe 200x2 bridged dedicated to one Evid, then the Kicker 800.4 bridged to each other Evid. A bridged amp pushing an 8 ohm load is design condition (equivalent to 4 ohms in stereo configuration). I think you run a greater risk of blowing your Fosgates running them in full range off your head unit.

Here's what I would do if it were my boat... Sell or trade the third Evid for some good boat speakers like Polk db675s or equiv. Dedicate the Kicker to the tower (adding a switch to kill the tower when not needed). Buy some decent boat speakers that will balance out that nice JL sub, like some Polk db675s or equiv., and another amp to run the boat so you can adjust the crossovers and gains appropriately.

Steve,
I agree with Mike. It would probably be better to either pick up another Evid and run 4 evids (2 in parallel on each bridged half of the amp) or sell one of them. As for running the fosgates off of the amp, you will probably be ok as long as your adjust your crossover and gain accordingly just as mike said. I sent you an email detailing how to set your gain. If you decide to run your fosgates off of the amp then you can adjust the output voltage from the amplifer to 12.65V with a 1Khz sine wave for the fosgates. This will give you 40W RMS. The amp with 2 evids and the set of fosgates is shown below.

Tom, your input on this has been nothing less than amazing. What formula are you using to determine output voltage using the different sine waves? I have a digita Fluke meter that will make doing that very easy.

I think I may have solved the problem...well with input from another source of course. Thinking outside the box, it was suggested that I use the JL 500/1 to run the 3 Evids, and the Kicker to run the sub. By doing so, running the 3 Evids in parallel brings them down to 2.67 ohms. The JL amp is stable from around 1ohms to 4 ohms and pushes 500W no matter what the resistance. 500W divided by the 3 sets of speakers is about 166W each (they're rated for about 150 continuous). The Kicker will push the sub off of two channels bridged delivering 400W at 4 ohms. I can either run the Fosgates off the other channels on the Kicker or the HU.

Thoughts?

(Message edited by leblanc1 on May 06, 2006)

The equation to get the voltage levels is the power equation P = (V*V)/R. You should set the voltage output at the speaker terminals with no load. Doing this will give you desired power into the load R. you can solve this equation for voltage if you know power and your load impedance. The voltage and power terms in the equation are RMS values, and voltage measured by your fluke is RMS (this is generally the case for DMM's).

About running the Evids off of the JL amp. It sounds like a good idea at first, but it's not going to work. The JL 500/1 amp is a class D amp, which means subs only. This is due to the fact that the amplifer only reproduces frequencies from 5Hz to 500Hz (bass frequencies). So if you are going to run the Evid's in a more full-range application you are stuck using the Kicker amp, or getting a different one.