Crossover setting Help

gfunk_nz · Post by **gfunk_nz** » Sat Sep 26, 2009 7:01 pm

I am trying to figure the best way of accurately setting up a crossover, about the only way I can think is by using a set tone at teh frequency I want to crossover at then pu a multimeter on the output and measure the voltage, then adjust the crossover until the voltage starts to drop off.
Is there any better way that anyone can think of???

Post by **smgreen20** » Sat Sep 26, 2009 9:45 pm

W/o all the right tools, that would be the cheap mans version of how to do it. Not the most accurate, but close enough.

Is there a reason you want specific freqs? Tuning by ear for what sounds good to you should be the first priority what w/all the phase and slope issues.

gfunk_nz · Post by **gfunk_nz** » Sat Sep 26, 2009 11:27 pm

So what would be the best way of doing it, the reason I want to do it that accurately to start with is to have a known starting point and ensure I don't play the tweeters too low

Post by **smgreen20** » Sun Sep 27, 2009 5:53 am

Unless you have an O-scope or a few $K to spend the DMM method will work. It's a starting point and the way you stated would be fine.

I see, I wouldn't want to go to low on the tweets either.

jbondox · Post by **jbondox** » Sun Sep 27, 2009 10:01 am

what is the parameters of the speakers?

where are they placed in reference with the other speakers?

Start with the specs of the speakers

if it is a component speaker, what is the factory x over point. what type of factory passive crossovers? 6/12/18/24 db slopes? that is your start

if the tweet has a freq response of 1k to 22k hz... well you know you don't want to dip down below 1k... though you also know that you don't want it to be overly predominant taking away from the mid or trying to be a mid... so you will want to start around the 2500 hz freq... if youare blending with a midbass woofer 5-6.5" if you are trying to blend with in a 4 way system... then you will want to adjust so it blends with the midrange.

if you using a conglomerate of mis matched speakers from different manufacturers... well good luck with that... you need to do R&D on your part... then spend the time tuning...

you do not need anything for test equipment besides your ears and knowledge of what you are doing

know the specs of the speakers
know the placement as test to see how it will be there
start with the basic settings of the crossover freq before you do anything else
start tuning the midbass and listen closely to what it is doing by itself
get it sounding perfect
start blending the tweeter to it
get that sounding awesome

most importantly is x-over settings, gains, and if you have a processor that can do time alignment... that is basic math with a measuring tape...

overall your ears are the best tuning

gfunk_nz · Post by **gfunk_nz** » Sun Sep 27, 2009 10:59 am

I don't personally have a scope, but have access to them at work so that's no drama.

The speakers are Ascendant Audio Havoc mids and tweeters, they haven't got the crossovers out yet, it was suggested a crossover point of about 2200 for the mid and 2400 for the tweeter. I might set up the ZX450 to run actively then before hooking up the tweeters setup the highpass on the fronts which will give me the low pass for the mids and do as suggested and get them sounding sweet.
The mids and tweeters will be going down low in the kicks same as I have now, although a somewhat different enclosure due to going from a 5.25 to a 6.75"

Post by **Eric D** » Sun Sep 27, 2009 1:31 pm

Do you have a laptop computer? Download this software...

http://www.trueaudio.com/rta_abt1.htm

Run the sound out on your computer to the RCA in on the amp. Run the amps outputs to your mic input, and set the gain all the way down. Make sure to get the mic (-) on the ground terminal (not the ones used for bridging the amp, the remaining ones).

You can run a pink noise signal with it and look at the input. Then you can perfectly set the crossover where you want and see it in real time.

knightrider358 · Post by **knightrider358** » Sun Sep 27, 2009 2:33 pm

wow eric thats great info that should be in a How to section

gfunk_nz · Post by **gfunk_nz** » Sun Sep 27, 2009 5:21 pm

so when you say not the ones used for bridging the amp do you mean not using the R- I think it is, but instead use say the left channel on both front and rear only?

Post by **smgreen20** » Mon Sep 28, 2009 4:41 am

Eric D wrote: ..... Make sure to get the mic (-) on the ground terminal (not the ones used for bridging the amp, the remaining ones).

Do you have any pics to show us exactly how?

Eric's full of these ideas so it doesn't surprise me any that he'd have a way.

Post by **Eric D** » Mon Sep 28, 2009 6:38 am

On a typical 2-channel amp for example, you have 4 terminals for the speakers. One is the right (+) and (-). The other is the left (+) and (-).

To make an amp bridgeable, one of the channels is inverted in phase 180deg, and then the terminals are swapped. When you bridge the amp, the signals will then add for twice the voltage.

The terminals used for bridging are the "live" terminals. The remaining two are the grounds, or datum grounds for the input and output circuits. You need to make sure you connect the (-) or shield of the mic input on your computer to one of these grounds, not a live terminal. You then connect the (+) of the mic line to one of the bridgeable terminals.

Many class D amps are internally bridged, so you cannot do this.

If you end up connecting the (-) of the mic input to one of the outputs of the amp (live terminals), you may destroy the amp or the laptop. This is because you are grounding the output which is like a shorted speaker.

Now, this does not apply to all line inputs or all o-scopes. Some are isolated and you can connect them either way with no issue.

Please read this for more detailed info....

http://www.bcae1.com/bridging.htm

gfunk_nz · Post by **gfunk_nz** » Mon Sep 28, 2009 10:53 am

That's awesome thankyou, I shall have a play with it