Cross over help

[guru_jeff]

I'm designing a 12db/octave x-over this is a 3 way design and I'm using JBL speakershop crossover module. Each cabinet will have 2 Hivi M8N, 2 M5N and 1 K1 tweeter.

I'm trying to get a nice smooth transition between the mid and the tweeter.
If you look at the FR for the M5N
http://www.partsexpress.com/pdf/297-436.pdf it jumps up about 4dB at around 1K Hz I would like to smooth that out

Here is the FR of the tweeter


http://www.swanspeaker.com/product/htm/view.asp?id=30
I'm crossing over the woofers at 150Hz

HiVi recomends > 2500 Hz crossover point.

I'd like to get some feedback on what crossover points I should use?

[noodle_snacks]

For that woofer i'd shoot for around 2khz, no idea about the tweeter. Use a larger than normal inductor on the woofer crossover in order to start the roll off a bit early and get rid of the broad peak from 1-2khz, you will need a notch at the 5khz peak, and possibly another for the 12khz~ peak. The 2.5khz recommendation for the tweeter might make this crossover a bit low however, it may be nessicary to choose a different tweeter for optimal results, at any rate you will probably need to go with a 4th order crossover. To be honest with you, i would not be personally use metal coned drivers without measurement equipment.

[lndm]

I think you could cross at 2k5, but I wouldn't build my own crossover for that woofer at 2k5 unless I had some basic measurement gear and a simulator, or some good measurement gear and some time.

You might consider a pre-made crossover if it is specifically for these drivers/box combo.

[guru_jeff]

I will be making my own crossover this is DIY central and I believe in DIY instead of the kits. Yes I will have a measurement system. I'm making my own with an ECM 8000 mic and I have access to an RTA With that said.

Does anyone have a xover software recomendation? The JBL speakershop crossover design software that I'm using only has 1 crossover pt. IE If I select 2500 Hz I assume it will be 12dB down at that point which makes the rolloff start at 1 octave lower for the mid and 1 octave higher for the tweet. like the previous post said I would like to roll the midrange off early and maybe set the xover pt for the tweeter higher.

I really don't think I need a notch filter nor a 4rth order is necessary. The 5kHz peek is about 6-8 dB and I start rolling off at 1kHz it should be 30dB down by that point. I guess I'll see when I measure it.

[lndm]

Originally posted by guru_jeff
Does anyone have a xover software recomendation?

You could plot your response and impedance, and their phase data with your RTA software, or if you can't get a reliable measurement you could sim your baffle with http://www.pvconsultants.com/audio/d...ownloadbds.htm
and combine this, and a low end box sim, with your data from parts express.

You could then put it into http://www.pvconsultants.com/audio/c...r/xoversim.htm

The JBL speakershop crossover design software that I'm using only has 1 crossover pt.

The abovementioned software is completely 'free range'. All nuances will be shown, and anything you could call a crossover, can be simmed. There is a learning curve, but IMO this just means it's worthwhile

I select 2500 Hz I assume it will be 12dB down at that point which makes the rolloff start at 1 octave lower for the mid and 1 octave higher for the tweet. like the previous post said I would like to roll the midrange off early and maybe set the xover pt for the tweeter higher.

This is how I would approach it if I didn't have the tools needed to subtly work out the problem. If I did, I would iron out that peak, being aware of phase anomalies, and cross it where I really wanted it to be crossed. I would not overcompensate the peak any more than I would undercompensate it.

[guru_jeff]

I would just like a simple x-over software program and a starting point of what frequencies to cross over my 3-way at.

I will use the measurement system and iterate from there.

[lndm]

There are simple crossovers (text book ones) and there are real world crossovers. If you choose to put this fact aside, then at the very least may I suggest you research impedance rise compensation. This is where you apply a resistor and capacitor (in series with each other) across the woofer to balance the impedance. Then add the crossover, following noodle_snacks' advice.

You'll also need to consider the effect of the baffle, and that the low frequencies will be reduced a few dB. Some find it useful to fix this with their crossover. You should be able to measure this.

Good luck

[guru_jeff]

You guys are making this a bit too complicated. I want to start off SIMPLE. I will take it from there AFTER I measure the system. If I need things like impedence balancing, 4rth order crossovers, baffle considerations etc etc.

Can someone please just answer my question? Is there a simple/easy to use crossover program/software that I can use? Also what is a good starting frequency to crossover my mids and tweeter?

I will iterate and make it as complicated as you think it needs to be after I get my initial crossover done and after I measure it. I also might leave it alone and not spend lots of money if I like the way it sounds.

Thank you

[noodle_snacks]

settle down jeff, you are telling us we are making things complicated, I think you are over simplifying things. You will need to employ some response shaping mechanisms on the woofer in order to get a crossover that works properly.

it is pretty clear from the above discussion that a good tweeter/mid starting point would probably be 2.5khz, and most probably 4th order, this goal would be difficult to achieve without measurement equipment since you will have to notch out the peaks in the woofers response, and use some sort of impedance compensation to counter the woofer's rising response.

Its not clear if you need help on the crossover point of your woofers, however i would try and use an active crossover. If not possilbe then cross your woofers as high as possible before beaming and/or distortion occurs (will save on the cost of crossover components)

Speaker workshop is powerful, and would be my recommendation, but many would not call it easy to use (I don't personally have trouble), I will let others comment on other packages (for the most part not freebies)

[richie00boy]

Originally posted by noodle_snacks
settle down jeff, you are telling us we are making things complicated, I think you are over simplifying things. You will need to employ some response shaping mechanisms on the woofer in order to get a crossover that works properly.

He's simply telling you the truth to help you. Adding impedance compensation is not at all difficult and is necessary, unless you don't mind binning your crossover components after your first pass.

I'm not convinced you need a 4th-order crossover, but certainly there are some aspects you simply can't ignore.