The crossover in my current punch amp only goes as low as 80 and it's too high for my ears. Unfortunately this is not one of those punch models that have XCards so I cannot modify the crossover point. I was looking at these inline crossovers online that plug between the RCAs coming from the HU and the AMP and I can get one with a LPF of 50 or 60. Are they any good?

Thx!

 

Look for an electronic crossover, it would be best

 

Agree, active/electronic pass-over will work best.

 

Your least expensive solution is a passive crossover. The major downside to passives is they eat up a significant amount of power during operation since the signal running through them is already amplified. As power goes up, however, the components need to be beefier, so there's a break-even point cost-wise.

Active networks split the signal before it is amplified, so you don't have to worry about losing serious power through it. The major downside is you'll need an amp for each band you split your music into. Actives are significantly more expensive than passives, but their tunability is what you get for that money. With an active network, you can split the bass frequencies out to an amp specifically designed to push heavy loads at low frequencies and not worry about it wasting power trying to amplify high-frequency signals. The same is true for mids and/or highs with another amp(s).

I won't suggest modifying the internals to your amp for two reasons...it would take a while to figure out what you want to modify, and you'll definitely void your amp's warranty.

 

Passive crossovers in the output side of an amp do consume power, but when put on the input side the loss is probably insignificant, and can be made to disappear since you can adjust the input sensitivity (on the amp) to make up for it. And since it's on the line-level side, there is no power dissipation to speak of, so that's not an issue.

I've not seen the in-line crossovers you talked about, but I found these at Parts Express. At least they have a 12dB slope, which is good.

I wonder how the makers of these devices handle the impedance problem? All passive crossovers must be designed for a fixed output impedance. A subwoofer passive crossover (between the amp and speaker) rated at 100 Hz and 4 ohms, will turn into a 200 Hz crossover if used on a 2 ohm speaker. So on these RCA crossovers, how do they know what the input impedance of your amp is? It might be 10k, it might be 50k, so that leaves a lot of room for error.

The only way I can think of handling that problem is to build a load resistor into the RCA crossover, low enough that differing amplifier input impedances won't affect it significantly. Something like 1k would be low enough. But you will definitely have to adjust your amp gain if that's the case.

If you get them, let us know how you like them. Or, you can buy an old (but never installed) active 3-way adjustable cross-over of mine for $40 plus shipping. If you're interested, PM me and I'll send you pics.

 

Thank you all for the input.

modifry: That's the kind of crossover i was talking about, only that the manufacturer is different. I was thinking on the same lines as you said, since I plan to put the crossover between the HU & the amp. I have an amp that's set to 1/6'th the gain right now and there's lot more unused juice if I want. You have raised a very important question about impedance and now I'm not so sure anymore. I'll try to find some more info on this issue and let you all know.

:-)


[QUOTE]Originally posted by modifry
[B]Passive crossovers in the output side of an amp do consume power, but when put on the input side the loss is probably insignificant, and can be made to disappear since you can adjust the input sensitivity (on the amp) to make up for it.

 

Input impedance is usually between 10k-100k, with most being closer to 10k. Much lower and you start to run into stability issues. However, since the output impedance would be a handful of ohms, the difference in input impedance between 10k-50k is trivial.

 

Output of what? (serious question - I'm not following what you said)

 

Mas, you need to be careful here. If you cut the sub off at 50 or 60 Hz you are going to need your other speakers crossover point to be lower also or you end up with a hole in the freq. range.

What are you finding offensive about your current setup? Is the low output too low? Is the bass sounding too tight?

Like everyone has suggested, get yourself a good active crossover and also consider an Epicenter. I have this and it make a huge difference in my system.

Here is a pic:



You can also download the manual here

 

Thanks for the comments, I'll look into the epicenter you mentioned.

I've never had a sub crossed over higher than 60. The sub right now sounds too "boomy". I tried another PPI amp with the built in crossover set to 50 and I was happy :-) I know it could be many other things causing this boomy sound but you know there's not much room in this car to experiment with. My fronts are crossed over at 60, I don't think it's too bad of a "hole".

[QUOTE]Originally posted by matrix
[B]Mas, you need to be careful here.