Why is my system louder with JBL GTO5EZ vs JL HD900.5 Amp?

[KChiefin29]

Hi, I just recently set my gains on my JL HD900.5 amp. Using a mulitmeter...I set the speakers at 100 watts @ 4 ohms. The sub channel was set to 500 watts @ 4 ohms.

This equaling around:

20 V on multimeter for speakers

44 V on multimeter for sub

My volume was set at 25, which is roughly 80% of 32...max on kenwood x997. For the sub I used a 50hz frequency and 1000 hz for the speaker test.

With all this said and done....I am very disappointed in the results. I initially was using a JBL GTO-5EZ amp, which in my opinion was much louder and seemed more crisp and clear. I could even hear the tiny details such as finger slide on acoustic pieces... The gains on the JBL was set with their test cd. The switch was made due to the size of the JBL amp...

Now if I had to be honest...The JBL amp got much louder than the JL. I also wanted to mention that I didn't notice any gain in SQ with the JL amp....WTH? I figured I was making an upgrade...but seems like I made a terrible choice going with the JL HD900. Now is this due to the Class AB vs D on the JL amp?

Is it safe to turn up the gains on the JL amp past 100 watts?

I believe the JL @ 4 ohms is rated at 100watts x 4 for speakers and 500 watts x 1 for the sub channel.

If anyone has any advice, please let me know... Thanks.

Setup:

Kenwood X997 HU

JL HD900.5 amp

JL C5 - 650 components

Polk mm651um

Polk SR104 sub

triple layered dynamat extreme on inner and outer door panels + rear.

Click to read more...

 

[KChiefin29]

Decided to raise the gain on the sub for 700 watts

Speakers are set on High Pass @ 75 hz

Sub is set at low pass @ 80 hz

 

[TaylorFade 10+ year member]

Funny thing about A/B on subs... it *sounds* louder. Some will tell you that it has to do with damping factor. But that's hogwash...

... or is it?

Another thing is that the JL is regulated. So you're getting more power across the entire bandwidth (virtually) regardless of rise. With the JBL, you're likely to have a spike in output around tuning; and that peak may be why it *sounds* louder.

 

[Jepalan]

The HD900.5 has some strange specs in it's user manual. It looks like it is optimized to drive 4-ohm loads on the main channel speakers. Your Polks are 2.7ohm. Maybe that has something to do with it?

I find this confusing...

Main Channels @ 4 Ω 100 W RMS x 4

Main Channels @ 3 Ω 75 W RMS x 4

Main Channels @ 2 Ω 75 W RMS x 4

Main Channels @ 1.5 Ω 75 W RMS x 4

 

[LosIsATool 5,000+ posts]

The HD900.5 has some strange specs in it's user manual. It looks like it is optimized to drive 4-ohm loads on the main channel speakers. Your Polks are 2.7ohm. Maybe that has something to do with it?
I find this confusing...

Main Channels @ 4 Ω 100 W RMS x 4

Main Channels @ 3 Ω 75 W RMS x 4

Main Channels @ 2 Ω 75 W RMS x 4

Main Channels @ 1.5 Ω 75 W RMS x 4

It's regulated. You can't look at it the same. Personally I don't like the HDs. Also with that JBL and the EZ you where getting every bit of power it had.

 

[KChiefin29]

Alright, well I decided to re calibrate the gain settings with the multimeter. The speakers are at 21 Volts and sub is at 54 Volts....which = 110 watts to speakers and 700 watts to the sub.

The Polk SR104 wants 700 watts rms...

Sonic bass boost or what not is on as well. Now I'm hearing that there are ways to squeeze more out of my system....also im seeing a low voltage and high voltage output switch on my JL amp. Currently it is set on low voltage output.

I think my lack of experience is pretty obvious....so what's the next step as in tuning or getting more out of my system?...trying to take baby steps so I can learn as I go. Thanks guys.