604E crossing over

[thinking]

I have always run my set of 604E's with the stock crossovers, but I have this Rane AC22 sitting here that I really ought to cross them over with. Just wondering what settings some of the rest of you have arrived at with this combination, (frequency and delay) as I am sure there are a number of them out there. I will still set them up with a RTA, but sometimes it's nice to know you're in the right ballpark. From reading the manual I'm guessing that 1500 hz and a setting of about 2 on the delay?

[donaldpatten]

Thinking

I have three 605A 's just back from Great Plains for Re Mag & Re Coning.They Did a surperb job . I have built passive time delay crossovers (really a work in progress )
I use a eMac computer with a Scope and FFT signals and analysis. I also have music software to generate tones etc. My test signal for time delay is a 1 kHz tone edited for only 1/2 of a cycle. This pulse is followed by 0.2 seconds of silence and repeated many times. I burned this to a CD and put my CD player on ?track repeat?. An omni microphone is suspended 12 inches (30 centimeters) on axis in front of the speaker. The micpreamp output is connected to the eMac input for Scope time delay and FFT frequency response graphs.

The software I use is SignalScope, SignalSuite, Peak 4 (G4+), and Toast 6 Titanium.

The Rane has an adjustable 0-to 2.0 msec LF delay . My 604s require about 0.4 msec delay . The older 604Es are deeper and require more delay ( try 0.5 ) . If you have newer speakers with alnico magnets try 0.2 msec.
The crossover freq spec is 1550 Hz.

Don

[Todd W. White]

The new Iconic DN604E Passive Crossover (designed by Jerry Hubbard for us) has a crossover frequency of right at 1500 cycles - it's about all that the small horn used on the 604C-G series can really do...

[donaldpatten]

I apologize for a typo : My * 605s * require about 0.4 msec delay.
Don

[thinking]

Thanks for the replies, they will help, but what I was really getting at was the inherant ambiguity of the Rane AC22 delay adjustment. Apparently the amount of delay induced varies with the crossover frequency, so they just put some numbers on the dial that are apparently meaningless. They do have a chart in the manual that gives a rough approximation, but they measure it in inches of offset instead of miliseconds (but I can convert that) I'm also guessing that since the numbers are apparently not related directly to real units, that they are not calibrated as such, and I'll really have to measure the response to get it right.

[Art J.]

I am also using the Rane 22.
If you want it right, you will have to measure. This also applies
to the crossover frequency. In my case I crossed at 500 but
the dial read more like 400. I used an audio oscillator, dual
trace scope and spl meter for the tests. I tuned the phasing
control for maximum spl at the crossover frequency. It was
a very delicate adjustment and the dial pointers are useless.
Their is a very low level hiss in my Rane 22 and I would like
know if others have that too. Maybe my unit is not up to specs.
Its a later model with the outboard power supply.

[donaldpatten]

Thinking
If you have an oscilloscope or a PC ( get Scope software ) ; you can see the two pulses ( LF & HF ) and just dial them in to overlap .Use the test pulse I described above . Connect the Scope input to a microphone preamp and a Mic positioned 12? on axis of your speaker . Also connect the Scope Trigger to the Woofer amp output . Check the LF & HF speaker scope signals individually and then together.
Don

[thinking]

Art J.

Their is a very low level hiss in my Rane 22 and I would like
know if others have that too. Maybe my unit is not up to specs.
Its a later model with the outboard power supply.

Not sure about the AC22, but I have had several of the Rane EQ units that had bad caps on the circuit board, the result was always that the associated frequency control didn't have any effect. So you might have a look at some of them on the AC. I will also add that Rane is very good about support, you can get replacement parts without a hassle.

[Todd W. White]

A minor correction -

Jerry Hubbard just got through measuring a 604E for me, and he says that the absolute lowest that the C-G horn will go is 1700-1800 Hz. It's just too small to work lower than that.

Sorry about the 1500 Hz I posted earlier - I got that number burned into my head from the 604E spec sheets when I was young, and it just popped out...

[David Deratany]

Todd,

He didn't by any chance measure a "B" horn, did he?

Just curious.

Dave