C400.4 & C500.1 settings

zgw8

Hi all - I have both the C400.4 running my front channels and the C500.1 running my two 8" subs. I have a couple of questions:

1. For those of you that run the amps along with Momo speakers throughout, do you use the Pre-EQ or do you bypass and use the filters in the headunit?

2. Both amps have an output setting (Low/High). On the 400.4, the manual states that if you have a high output headunit (4 or 8 volt) that you should set the output to high. On the 500.1, it refers to whether you are using RCA or speaker wire connections. Isn't it the same setting? When I set the 500.1 on low, it is sonic overkill?

Peace,

zgw8

neomagus00

high vs. low - this just changes the range of the gain dial... if you are putting 4 volts or more in, use 'high' (i run RCAs off a 6.5V HU, so i use 'high')... the mention of speaker wire connections is there just because they are usually above 4 volts. if you're running 5V, set to 'low', you're probably going to go into clipping.

pre-eq - on the 400.4, this turns the amp into the perfect machine for bi-amping a set of polk components... if you're using it to biamp, i'd use the pre-eq button (make sure you put the right speakers on the right channels!!!), otherwise, it's useless. i dunno what the button does on the 500.1, if it has one...

zgw8

so, my Clarion DXZ955 is a 4 volt output to the RCAs. I was told that anything above 2 should be set to High. Your post indicated that a 5 volt HU should be set to Low? Is that what you meant?

MacLeod

On the 500.1, the Pre-EQ is a 9db bass boost centered on 40 Hz I believe.

neomagus00

zgw8 wrote:

so, my Clarion DXZ955 is a 4 volt output to the RCAs. I was told that anything above 2 should be set to High. Your post indicated that a 5 volt HU should be set to Low? Is that what you meant?

no, you're right - high voltage, set it to 'high', i got mixed up

1996blackmax

MacLeod wrote:

On the 500.1, the Pre-EQ is a 9db bass boost centered on 40 Hz I believe.

I would not want to use a setting that introduced any boost into my sound system, let alone that much :eek: .

98thumpin

yeah might be a bit overkill unless your into having your balls shook off

Thom

Who isn't?

MacLeod

1996blackmax wrote:

I would not want to use a setting that introduced any boost into my sound system, let alone that much :eek: .

Thats actually pretty low. Most bass boosts on amps are at least 12 db and some are even 18! Bass boost isnt always a bad thing, sometimes if your sub has a response hump or rather noticeable roll off below 40 Hz, a boost can sometimes help.

Plus, if you just like a lot of bass in your music theyre good for that too. I like having the option.

98thumpin

good point

1996blackmax

Just remember that for every 3dB of boost you are asking your amp to double its power in that frequency range. I think many amps would find this hard to acomplish when pushed to high performance levels. Now if you set your gains accordingly, that is another issue. I just don't think many people know about this, and will make their amps clip when not being responsible with their volume knobs.


I like to attack any humps in my frequency response with my Parametric EQ. I drop some dB's accordingly. I do know what you are saying Mac, I have used it in the past. I just feel that if your system is properly setup and tuned in, it should really not be necessary. I also know that taste also plays a role in this, just be careful with the boost is all .

MacLeod

Huh? Youre not doubling the power for every 3db in bass boost. If that were the case then the 18 db bass boost on a PPI 500 watt amp is making 3000 watts?! No way. Its simply doing the same thing your eq does. When you adjust your eq up it increases in db's.

You are right that itll make your amp more likely to clip but as long as used correctly, a bass boose isnt a bad tool to have.

1996blackmax

Read it again Mac . For every 3dB of boost that you dial into to your amp, you are asking it to double it's power into that frequency band. For example if your boost is at 45Hz and you boost it by 3dB it will require your amp to double its power in that range when compared to the sorrounding bands that are not boosted. Reason why a person doing this will run into problems when pushing their gear at higher levels. That is why I like to cut the peaks in my system as opposed to boosting the other frequencies to match it up to the peaks.

That PPI 500 watt amp will have problems if you turn it up loud and you are also dialing it 18dB of boost. It will not make the 3000 watts, that is not what I am saying.

1996blackmax

A link from JL's site. It also says in there to be careful with the boost. The cool thing about their parametric boost is that you can also drop the level on it too.


http://mobile.jlaudio.com/pdfs/Parametric_Equalizer.pdf


A little part relating to the bass boost from their site:

"Some basic tips to get you started in the
exploration of the Bass EQ...

4) Don’t go crazy with the boost knob... there is 15dB of
boost available (which is a lot). Begin with a low boost
setting (around 3 dB) and try to stay below 6 dB
whenever possible. Remember that for every 3 dB
of additional boost you dial in, you are asking the
amplifier to double its power output for a given signal
in the boost region."

MacLeod

OK, I thought you were saying if you turn on a 6db bass boost youre making the amp double its power. I get ya now.

Still, a 500 watt amp with 18 db bass boost aint gonna produce 3000 watts even if its just at 40 Hz. Hmmmmm. Upon further reflection.....Im really not sure how the hell that works. Take my Crossfire and its 6 db boost. I wonder if instead of making 4 times the power if its taking power from the other frequencies rather than just making more power. I never really thought about this. I knew it increased the response at that particular frequency but I never thought about power output.

Where the hell is Vinny?

neomagus00

you're still limited to a maximum of 500W, no matter the frequency. Say that at 80 Hz that gets you 100 dB, and that your system is totally flat. Then, that same 500W will get you 100 dB at 40 Hz. Now dial in 3dB of boost at 40 Hz. You can still output 500W at 40Hz, to get your 100dB. But, without changing the volume level, you'll now only see 250W at 80 Hz, for 97dB.

that help a little?

MacLeod

Thats kinda how I thought it worked.....er...I mean, Yeah! I knew it all along!

Hell, I just listen to them. Ill leave the knowing how they work to the smart guys.

1996blackmax

I knew you would come around Mac .

MacLeod

No, I was still right. Techinically, its not doubling its power.....ah who am I kidding. I dont know **** about this technical stuff. I need to drink a beer.

1996blackmax

That sounds good to me right about now. Thing is I can't. Just got home from work and have to go back and do the night shift in about 6 1/2 hours. I hardly ever drink, then when I have the urge I can't .