Help setting the HPF and LPF on my amp

[Nairblop 10+ year member]

only mids ganna be running active, the HU is only for tweeter....the HU is a Eclipse CD8445

If I'm not mistaken, if you're not using the passive crossover that came with your component set and have the tweets wired directly to the HU (which, in your case, has onboard sound processing/crossovers) then you are running active.

Let's say, for example, that you've used the crossover on your HU to send the tweeters all frequencies that are 2KHz and above. In this case, you'll want your mids to pick up frequencies between 2KHz on the high end, and, say, 80Hz on the low end.

tcguy is right in that this is what's called a bandpass setup. I don't know what amp you have, but my amps only have the option of either low pass or high pass. If your amp is similar, something you could do is to use your HU to set a low pass filter on your mids at 2KHz, thereby allowing only frequencies below 2KHz to "pass" to your mids. Then you could use the high pass filter on your amplifier to allow only frequencies above 80Hz to "pass" to your mids. If your amp has some kind of bandpass option, then, using my example frequencies, you'd set the high pass at 80Hz and the low pass at 2KHz.

This is the best I can explain what I think you're trying to ask. If I'm wrong about something here, hopefully someone that knows what they're talking about will correct me //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[xDATx 10+ year member]

well thats why i asked how the tweeters are gonna be crossed because that all doesn't really make sense.

so what are you saying i can't only amp my 6.5" mids?

 

[Nairblop 10+ year member]

How about this: What components do you have and did they come with a crossover?

 

[xDATx 10+ year member]

If I'm not mistaken, if you're not using the passive crossover that came with your component set and have the tweets wired directly to the HU (which, in your case, has onboard sound processing/crossovers) then you are running active.
Let's say, for example, that you've used the crossover on your HU to send the tweeters all frequencies that are 2KHz and above. In this case, you'll want your mids to pick up frequencies between 2KHz on the high end, and, say, 80Hz on the low end.

tcguy is right in that this is what's called a bandpass setup. I don't know what amp you have, but my amps only have the option of either low pass or high pass. If your amp is similar, something you could do is to use your HU to set a low pass filter on your mids at 2KHz, thereby allowing only frequencies below 2KHz to "pass" to your mids. Then you could use the high pass filter on your amplifier to allow only frequencies above 80Hz to "pass" to your mids. If your amp has some kind of bandpass option, then, using my example frequencies, you'd set the high pass at 80Hz and the low pass at 2KHz.

This is the best I can explain what I think you're trying to ask. If I'm wrong about something here, hopefully someone that knows what they're talking about will correct me //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

they are actually stock oem tweeters, my amp is a RD Audio RD-504 and there is no bandpass option

 

[Nairblop 10+ year member]

I can find RD Audio, but nothing about that model. Is it a 4 channel or a 2 channel?

 

[tcguy85 10+ year member]

i'm so lost.

what do you have? what exactly are you trying to do?

you do understand that you have to cross the mids and tweets right? you can't just amp them and run them full range, and the tweeters have to have a high-pass or they won't last a minute.

 

[Nairblop 10+ year member]

If you want to amplify your tweeters, you're going to have to have either a 4 channel amp or a couple of 2 channel amps. I don't know how you have your HU wired. For all we know, the crossover for the tweets that the factory used is still in effect. But if you amplify the tweeters, you'll almost certainly bypass the passive factory crossover, in which case you'll need to either highpass them with your HU or amplifier.

 

[xDATx 10+ year member]

I can find RD Audio, but nothing about that model. Is it a 4 channel or a 2 channel?

specs:

Rd Audio 50.4 4 channel amplifier

4 x 50W @ 4 ohms

4 x 85W @ 2 ohms

2 x 170W @ 4 ohms bridged

THD:

S/N Ratio: >105dB

Fuse: 2 x 20A

Dimensions: 11.8" x 9" x 2.5" (30cm x 22.9cm x 6.4cm)

 

[tcguy85 10+ year member]

hmmmm well it appears you can bandpass with that amp but only up to 2k it seems. so if the tweeters don't extend that low it won't do ya much good.

 

[Nairblop 10+ year member]

It looks to me like, since he has an HPF and an LPF on each channel, he can bandpass his mids using the amp. However, if your HU has the capabilities, which I believe it does, I think that would be the better option. Are you using any other speakers besides the one pair of mids and one pair of tweeters? If so, are you wanting to amplify them?

 

[xDATx 10+ year member]

It looks to me like, since he has an HPF and an LPF on each channel, he can bandpass his mids using the amp. However, if your HU has the capabilities, which I believe it does, I think that would be the better option. Are you using any other speakers besides the one pair of mids and one pair of tweeters? If so, are you wanting to amplify them?

no, no other speakers

 

[tcguy85 10+ year member]

can your HU do it all? can it control everything actively?

 

[Nairblop 10+ year member]

Ok, from the back of your HU you'll have two pairs of RCA cables (plugged into channels 1, 2, 3 & 4) running to your amplifier. Let's say you want to use channels 1 & 2 for your tweeters. Set the crossover selector on channels 1 & 2 on your amplifier to highpass. Then turn the highpass knob all the way up to 2KHz. From the corresponding speaker outputs on your amp, run speaker wire to the tweeters. Insert the remaining RCAs into channels 3 & 4 on your amp.

The more I look at your amp, the more I think that you probably can't bandpass your mids using the amp alone. Why they used two seperate knobs for high and low pass, I don't know. But I'm assuming if you select "full" rather than "high" or "low" on the crossover selector, you're going to be getting the entire spectrum of frequencies. If this is, indeed, the case, you have no choice but to set your mids at a high pass as well if you are only using the amp as a crossover. On channels 3 & 4, select high pass and turn the knob to 80Hz.

Now, you're going to have to use your HU to prevent all the really high frequencies from coming out of your mids. Go through your menu and find where you can select crossover points for channels 3 & 4. Use your HU to set a low pass filter at 2KHz. Of course, if I were you, I'd use my HU to do all the crossovers. Go to channel 1 & 2 crossover on the HU, set a high pass filter at 2KHz. Then you can (maybe) go to channel 3 & 4 and set a high pass at 80Hz (or 63Hz, or whatever works for you) as well as a low pass at 2KHz.

Do you know how to set crossover points using your HU?

 

[xDATx 10+ year member]

Ok, from the back of your HU you'll have two pairs of RCA cables (plugged into channels 1, 2, 3 & 4) running to your amplifier. Let's say you want to use channels 1 & 2 for your tweeters. Set the crossover selector on channels 1 & 2 on your amplifier to highpass. Then turn the highpass knob all the way up to 2KHz. From the corresponding speaker outputs on your amp, run speaker wire to the tweeters. Insert the remaining RCAs into channels 3 & 4 on your amp.
The more I look at your amp, the more I think that you probably can't bandpass your mids using the amp alone. Why they used two seperate knobs for high and low pass, I don't know. But I'm assuming if you select "full" rather than "high" or "low" on the crossover selector, you're going to be getting the entire spectrum of frequencies. If this is, indeed, the case, you have no choice but to set your mids at a high pass as well if you are only using the amp as a crossover. On channels 3 & 4, select high pass and turn the knob to 80Hz.

Now, you're going to have to use your HU to prevent all the really high frequencies from coming out of your mids. Go through your menu and find where you can select crossover points for channels 3 & 4. Use your HU to set a low pass filter at 2KHz. Of course, if I were you, I'd use my HU to do all the crossovers. Go to channel 1 & 2 crossover on the HU, set a high pass filter at 2KHz. Then you can (maybe) go to channel 3 & 4 and set a high pass at 80Hz (or 63Hz, or whatever works for you) as well as a low pass at 2KHz.

Do you know how to set crossover points using your HU?

yes i do, but it will do all the channels i can't select each channel

 

[Nairblop 10+ year member]

You can't set one crossover for channels 1 & 2 and then another for channels 3 & 4? Well, in that case set the amp like I suggested in the first two paragraphs above. Then go to your local audio store and get some inline lowpass crossovers for your mids so they don't get all the frequencies above 2KHz. Also, I'd be careful with the gains going to the factory tweeters. You might look into getting a budget friendly component set or looking on ebay for some aftermarket tweeters. I'm sure you could find something decent for pretty cheap.