I am currently working on an installation.
Bike=2012 Ultra
HU=Original
Front Speakers=Infinity 62.11
Rear Speakers=Polk MM651
AMP=Cerwin Vega B54.
I am setting the gains initially with a DMM and 1 khz -5db test tone.

I have the gains set for the front Kappas at 17.3 to achieve 150 watts. The amp says it is a RMS of 150 x 4 @ 2 ohms

For the rear speakers Polk MM651 2.7 ohms and RMS of 100 watts.

1) Do I have to turn down the gain to 16.43 to give me a 100 watts as that is the max RMS the polks are rated for? The peak is 200 watts but I know I shouldn't be running them at that level long term.

2) If I am correct then the Polks will not be as loud as the Kappas as I am running them at 50 watts less?

3) Once the gains are set, do I run these speakers in HP adjusting the cut off frequency or switch to Flat. I can set the front and back differently so please let me know if I set them differently.

Thanks
Jon

 

Did Polk fix the problem they were having with tweets on Harley's?

 

Both of your amp VAC calculations are correct. Good job!

The Kappas will be louder for two reasons. 1. More power 2. They're closer to your face versus a speaker that is already 2 feet behind you and the wind is carrying that sound backwards at 70mph.

The HP/AP adjustment is yours to decide. Let your ears tell you. Run them all pass and take it down the road. Turn it up and if you hear the speakers take a knee when lower bass is hitting, set the HP and start at 70-80, work down from there. Specs on both speakers say they will play down to 45Hz which I'm not buying and you won't hear while you're riding anyways. If it was ME, and others can absolutely disagree, but I'd set HP at 80, bolt the fairing on and hit the road.

 

I typically set my gains at 150% of RMS at max clean volume on the HU which for many HUs the norm seems to be at 75% or 3/4 volume.

If u had the juice u could indeed throw more juice at the Kappas but for sure u can throw some more at the Mm651s.

After u get the gains set from the DMM you can then make some small tweaks to get the fade balanced considering that ur TP is exposed to the wind a bit more. Aka, bump the TP up just a touch higher than the fairing.

2 pennies.

T.

 

cpbedor
Thanks for your comments, and confirmation. I fried the PBR300x2 I had in there previously running only the Kappas and had them set at all pass, it often would clip, so I was leaning towards the HP with the frequency around 80ish.

 

Tailwind what would be safe to push the MM651's to without blowing the speakers? 125 watts? I appreciate your thoughts.
Jon

 

You could throw 150 w at them all day.

Set up both sets with DMM, then fine tune gains by ear. The key here is to never deliver distortion to the speaker. The DMM is just a ball park figure based on specs, but your ears should be the ultimate judge.

Play your favorite song at 3/4 volume and adjust gains so that ur getting damn good clean sound out of the Speaks while also maximizing their potential. Do this for the front only then the rear only then both together.

T

 

I had a pair of the newer series where the problem was supposedly remedied. Went for a 90 minute ride at 80-85mph (just keeping up with traffic, what can I say) and had them cranked. Melted the tweeter stalk on one of them If I can ever get my hands on one to replace the burnt one, I'll try them again with the gains turned lower.

 

I got the Polks installed, Cerwin Vega b54 amp installed, pulled it out of the garage, and played a song, Living on a prayer by Bon Jovi. I picked this due to a good mix of lows mids and highs. I had the VAC on the Kappas for 150 watts, and the head unit at 13 bars right under the E on the volume. The song hit some lows and they clipped. Urghh. I turned down the gain, but they are not as loud.

The polks though, I had them set for VAC 125 watts, RMS states 100 watts, when I played them, same song, no clipping, and I could actually turn the gain up a little more for before they started to distort.

They sound really good, as long as it isn't from the radio.

BTW, thankfully installing the Cerwin Vega B54 Stealth amp I didn't loose any noticeable FM signal. The amp is mounted on top of the radio/CB module, under the Ultras fairing, and the the fairing went on without a problem.

So far I am happy with the Polks, I hope they hold up though.

I am disappointed that the Kappas 62.11 were clipping though and they are supposed to handle more power than the Polks, same frequency range and nearly the same db level, both at the same volume, and nearly the same power the Polks didn't clip even when I abused them for a few seconds and turned the radio up to max. I assume putting poly-fill in the fairing around the Kappas would not have any affect on the clipping.

Better than I had, but a little short of my hopes. I guess next will be the radio change out.

 

I'm gonna suggest you set the Kappas by ear. Meters are good but nothing is better than your own ears. I know for a fact the Kappas will handle more wattage than that and never flinch. Make certain the bike is running when setting gains.