Midrange driver to match with planar ribbon tweeter

[Rick Sykora]

looks like a pretty simple crossover. will need to know the values for the inductor at the top and the resistor in the upper left. Is the upper right terminal the positive input? If so, then the braided wire rising perpendicular from the board is connected to the woofer and the one going down the center hole connects to the tweeter. Please confirm..

 

[Certainkindoffool]

@Winkleswizard Thanks for the help!

The crossover is mounted behind the tweeter, the braided wire going up goes to the tweeter, while the wire going down goes to the woofer.

Edit: Unintuitive design choice for the upper terminals to go to the woofer, but that is indeed how it is labeled. The other set of speakers only has one pair of binding posts.

The inductor is rated at r= 0.389 1.35mH

The resistor is a 25W2 +/- 5%

I am missing a lead for my multimeter (apparently the price paid for loaning out tools). But, I will measure them all tomorrow, along with the resistance of the ribbon tweeter.

 

[Rick Sykora]

@Winkleswizard Thanks for the help!

The crossover is mounted behind the tweeter, the braided wire going up goes to the tweeter, while the wire going down goes to the woofer.

Edit: Unintuitive design choice for the upper terminals to go to the woofer, but that is indeed how it is labeled. The other set of speakers only has one pair of binding posts.

The inductor is rated at r= 0.389 1.35mH

The resistor is a 25W2 +/- 5%

I am missing a lead for my multimeter (apparently the price paid for loaning out tools). But, I will measure them all tomorrow, along with the resistance of the ribbon tweeter.

@Winkleswizard Thanks for the help!

The crossover is mounted behind the tweeter, the braided wire going up goes to the tweeter, while the wire going down goes to the woofer.

Edit: Unintuitive design choice for the upper terminals to go to the woofer, but that is indeed how it is labeled. The other set of speakers only has one pair of binding posts.

The inductor is rated at r= 0.389 1.35mH

The resistor is a 25W2 +/- 5%

I am missing a lead for my multimeter (apparently the price paid for loaning out tools). But, I will measure them all tomorrow, along with the resistance of the ribbon tweeter.

Thanks. Makes sense now. Having some idea of the resistance for both drivers will help. Also just to be thorough, need the value of the 3rd yellow cap in the upper set that are all wired together.

Would not do any new binding posts. Use the tweeter circuit as-is for now. You will be protecting the amplifier while taking measurements then. When you are ready for active, you can simply solder another capacitor in that will lower the crossover frequency to be less than the active frequency.

As for the woofer, simply disconnect the spade connector in the middle of the board and unsolder the connection on woofer positive terminal. If you smooth the solder evenly, you should be able to push the spade connector on to it. If you want less work, short out the inductor and series resistor.

 

[Certainkindoffool]

@Winkleswizard There are no official markings on the yellow capacitor visible. However, it has 6.97 written on it - which seems to be the measured value at assembly. I can't think of any way to measure a capacitor without removing it from the circuit. But, this is new to me.

The other resistor values corroborate closely with the written values.

Resistance of the tweeter was 5.1 ohm, other tweeter was 5.4 ohm - measurement taken from the crimped connectors at either end of the braided wire.

 

[Certainkindoffool]

Thanks for all the help - I've learned quite a bit from simply following this and other threads where your collective assistance was offered.

I ordered parts to proceed with the active setup.

Something seems off with the measurement software, as ARC and REW are giving conflicting readings. I have decided to just order
a proper calibrated mic before proceeding much farther. That was I can stick to REW, which seems to be pretty powerful software, rather than ARC. I'll also be able to upload an EQ profile to the dcx 2496 instead of depending on the PW Link ARC room correction.

Seems like the miniDSP Umik-1 is a common pick for a mic. I'll just order on of those.

 

[andreasmaaan]

@Certainkindoffool be sure to check in here before taking measurements of the speakers and designing the active filters. Measuring speakers correctly at home is quite difficult, although not impossible.

For quasi-anechoic measurements, which is what you'll need to take for the mid and high frequencies, I've always preferred HOLMImpulse over REW, FWIW. It gives better results with minimal tinkering (ofc, REW is far superior for in-room measurements, but that's not what you'll be doing at this point).

 

[Biblob]

@Certainkindoffool be sure to check in here before taking measurements of the speakers and designing the active filters. Measuring speakers correctly at home is quite difficult, although not impossible.

For quasi-anechoic measurements, which is what you'll need to take for the mid and high frequencies, I've always preferred HOLMImpulse over REW, FWIW. It gives better results with minimal tinkering (ofc, REW is far superior for in-room measurements, but that's not what you'll be doing at this point).

Could you elaborate on why you prefer it? Are there clear (dis)advantages to it, compared to REW?

 

[Certainkindoffool]

@andreasmaaan Thanks for the heads up. I had never heard of that program and will look into it. I do wish I had gotten into this 20 years ago. My stepfather used to have a sound room and all kinds of measurement tools when he had a business making custom monitors for musicians. Unfortunately, he sold them all to the company he ended up doing R&D for - that company has since closed shop.

Any suggestions on a calibrated mic other than the UMIK-1? Shipping time is a couple weeks to Canada, unless I want to play closer to CA$300 through Amazon.ca.

 

[andreasmaaan]

Could you elaborate on why you prefer it? Are there clear (dis)advantages to it, compared to REW?

Well, REW is a more comprehensive piece of software by far. The disadvantages of HOLM in terms of features are many and too numerous to catalogue. But for the functions that HOLM does perform, it performs them very well.

Anyway, for this specific task (taking gated measurements), HOLM seems to do a better job of auto time-gating without the user having to fiddle with too many settings. So I recommended it since in this narrow use-case it seems to work better out of the box, and I figured @Certainkindoffool would be happy to do as little mucking around to do as possible given this is his first go at measuring speakers.

@andreasmaaan Thanks for the heads up. I had never heard of that program and will look into it. I do wish I had gotten into this 20 years ago. My stepfather used to have a sound room and all kinds of measurement tools when he had a business making custom monitors for musicians. Unfortunately, he sold them all to the company he ended up doing R&D for - that company has since closed shop.

Any suggestions on a calibrated mic other than the UMIK-1? Shipping time is a couple weeks to Canada, unless I want to play closer to CA$300 through Amazon.ca.

I found the UMIK-1 to be pretty good for the price, but to be fair, I never measured it against a better performing mic to make a comparison (IIRC, others have online and have found it to be reasonably accurate). Be sure to load the factory-supplied calibration file that you can download from their website by entering in your product key. I think you'd need to spend significantly more to get meaningfully better performance (eg Earthworks M23R). But I'm not fully up-to-date on the current UMIK-1 competitors. IIRC, the Dayton UMM-6 is claimed to have similar performance. Perhaps others here have more experience or links to measurements/comparisons etc...

Pity about all your stepdad's gear. Nice that you're taking up where he left off though.

 

[Rick Sykora]

@Winkleswizard There are no official markings on the yellow capacitor visible. However, it has 6.97 written on it - which seems to be the measured value at assembly. I can't think of any way to measure a capacitor without removing it from the circuit. But, this is new to me.

The other resistor values corroborate closely with the written values.

Resistance of the tweeter was 5.1 ohm, other tweeter was 5.4 ohm - measurement taken from the crimped connectors at either end of the braided wire.

You are going to need more measurements with REW or equivalent. It looks as though Clements built-in some resistance into the tweeter (if it is a true ribbon). If you got a reading of 5 ohms straight from a disconnected tweeter, then you can hook up your amp to it without issues. While understanding the passive design may yield some useful clues, you will need the to measure the individual driver frequency responses to design an active crossover regardless.

Looks like you have help with measuring, so will step back and see what you find.

 

[Certainkindoffool]

@Winkleswizard

Thanks for the help. I will measure again at the tweeter leads, and compare them to the newer version.

It looks like this projects completion will be on hold for a bit. The guaranteed delivery date of the UMIK-1 is march 13th, unless I really want to overpay for it.

 

[andreasmaaan]

@Winkleswizard

Thanks for the help. I will measure again at the tweeter leads, and compare them to the newer version.

It looks like this projects completion will be on hold for a bit. The guaranteed delivery date of the UMIK-1 is march 13th, unless I really want to overpay for it.

That's a pitiy. It's not worth CA$300!