Just got the new DS800.4S EVO 4-Ohm amp the other day and I'm trying to read up quickly to start the install tomorrow. Again, for now until I can sort out the new speakers (WDXMoto-G2 or Arc Moto 602HD or ???), I'm going to stick with the Rokker 7.25" 2ohms I have already installed in the fairing and lowers.

Firstly, I'm reading the spec on the amp is:

800.4D EVO 4Ω
Power @ 12.6V @ 2Ω: 4 x 200 W RMS
Power @ 12.6V @ 4Ω: 4 x 110 W RMS
Power @ 12.6V @ 8Ω: 4 x 61 W RMS

Power @ 14.4V @ 2Ω: 4 x 261 W RMS
Power @ 14.4V @ 4Ω: 4 x 144 W RMS
Power @ 14.4V @ 8Ω: 4 x 79 W RMS


So, in reading Slydogs excellent pinned post on Setting Amp Gain, the chart is showing that for 200w (12.6v @ 2Ω) the output voltage should be 20.0v for 200w. And then, at 261w (14.4v @ @ 2Ω) the output should be 22.4 v for 250w. So I'm figuring somewhere between the 2 would be safe, say around 21.2v. or should I target the 22.4v? A little unclear on this. And then I am assuming you would check Ch 1 and then Ch 2 and if they are off a little, go with the higher of the two as the max? Then however I handle 1 & 2, I duplicate for 3 & 4.

The SD manual is saying to shoot for 20.0v. But that's at 200w which is the spec for 12.6v so knowing the bike running will be around 14.0v-14.1v, I'm not sure what to shoot for?

Also, Slydog was suggesting using the 1000hz -5db tone (1khz). However, SD is saying to use 60hz +0db, and using X-over of Full. Any thoughts on which to do?

Lastly, once I get the voltage and gains set, I think I need to set the X-over to HP, and I'm thinking setting the cross to 80 to 90hz. Any thoughts there? J&M has never provided clear spec's on his Rokker 7.25" speakers, in particular Freq Range or recommended settings, so I'm really not that sure what to target? Also, the cross over adjustment screw isn't all that granular wiht the markings, so how do you know exactly what you are adjusting to? Is there a way to measure it with a multimeter? or do you just eyeball it?

If someone could kindly slap me in the right direction, with what target I should shoot for, I would greatly appreciate the help. Thanks guys!

 

If you send those Rokkers that much power I guarantee you will see some magic smoke come boiling out of those speakers.

As an added note: none of the speakers you mentioned are going to handle that much power.

 

I agree on the Rokkers.

But I think with the bike going the best he will see is 12-13v at best. (110w)
Most of any quality coax will handle that.

The Arc's will probably be a little less efficient but handle more power.

 

Well, since I made this post, and pundered this further, I came to the conclusion that I should probably adjust my target voltage to 20.0v. The speakers are rated for 170+ watts RMS, or so John claims, and I don't typically play the music wide open blaring all the time anyway. No doubt if I push them they won't last long but I really don't care much about them. I'm just going to run them until I can get some insight on this next gen of coax's coming down the pike.

Also, regarding the other new coax's speakers not handling this amp, I thought that with 4 Ohm speakers, the amp will then only be putting out 144w which based on that chart is around 24.5v. I thought the WDXMoto-G2 and the Arc Moto 602HD would be able to handle 150w RMS? If not, I will obviously need to turn down the gains a bit, and target a specific output voltage to be safe, but I'd rather opt with a higher output amp that's turned down a bit, than over push a lesser amp, I think, right??

 

I don't se any problem with feeding the ARC 602 HD (rated at 125 rms) or the WDX Moto (rated at 175 rms) 144 watts rms (if the SD 800 will even produce that much power)...even the Rokkers should handle that amp, as long as you set gains, properly (on the low side) and don't crank them WFO!

 

Never said they wouldn't handle the amp, I simply meant they wouldn't handle the watts you quoted. I honestly wish they would take that sticky down. It will get a novice in far more trouble than any good that it will do.

 

For a novice like me, having something tangible is a heck of a lot easier to get into the ball park, rather than going by ear which is very subjective. I fully understand that once I set the gains to whatever value you all agree I should shoot for, then that's just a starting point. I think I'll just mark on the amp where 20.0v is, and then tweak it slightly from there.

That said, on the HP cross over, any thoughts on what to shoot for with these speaks? 80hz or 90hz, or something different? And then, how do you tell if the 80hz is really 80hz? Or is this an ear thing too?

Thanks!!

 

It's actually all pretty much an ear thing. I would start them at 80 and work from there. In the end it's ultimately all about pleasing your own ears.

 

you go ahead and send those rockers that much power and see what happens, pretty sure you wont like it. The SD amp will make the power, all the other quality 6.5's that we speak about here will work just fine with that amp. I currently run the old version and have not had any issues with ANY of the MANY speakers that i;ve tested it with, but i have to agree with bates,,,,set the gains by ear first , backing off at the point of distortion,,,if you absolutely feel the need to know the voltage, go ahead and check it at that point, that way you will know what your speaker can safely handle without damage, as the distortion is one of the things that will hurt it. there is a place for the voltage measurement, but if you dont have a lot of experience with both the process and the products, i'd say do it by ear, then test, then tweek.
m

 

And if u need a simple way to acquire volt numbers there is a free phone app called Ohms Law that will tell u exactly where u are or where u want to be based on your input

T