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Misc project adventures

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  • edited May 30

    On 12db alignment have 3 ohm dip around 70-110Hz. Z slightly better on the 3rd order at around 3.5ohm. Bounces around 4-6 ohm up to 2k then around 6-8 after that. Not worried as I will run off amps that can handle it rather than the receiver. Currently happy with the even-ness at various volume levels.

    4 ohm drivers across the board. When I bought the wo24's, Madisound only had the 4 ohms ones in stock (month or so after SDC2023) and when got the sb12cac's at the kick off of holiday sale, so the 4 ohm ones as well.

    Somedays wish would incorporate recessed box for xover - but think it better to achieve end state vs continual f'ing around.

    Can see being uncommittal on xover in these abominations that this 3way build replacing, a 2.2 setup - perform great but low WAF but she's like whatever. Note to self, rattle can'ing larger speakers blah, know to just bust out the sprayer for better results. Sdx10's not sure what do with yet. Budget-ish Faital10-peerless prob go to garage, get crazy loud and something appealing about large format mid range, 1.6k xover and had to 1 ohm pad the woofer for level matching since they second hand 4 ohm'ers. They're sealed with no intention of doing below 80hz, nor would many pro drivers anyway, but of course have sacrificial sub hidden away in garage too.

    Steve_LeeWolfjr@mac
  • edited June 12

    Found need to work on voicing the chunker 3 ways once moved to family room, too much bass. Should have known seeing the 1mh pair of coils for sb12cac's low pass given the satori 9.5 4ohm sensitive.

    Anyway.... SDC2024, think they should allow GRS drivers in the 'dayton only' category. When was ordering some other supplies, bit the bullet and bought https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126?quantity=1 Really like the sound of the Heil's on Nick's Indy24 entry, figured try frugal GRS mid-tweet and cross around 1k with the dual epic7 bases have.

    Thought I saw bread crumbs that Ben may enter the dayton cat? (sig180 and ribbon)

    Imagine i should register, keep testing fate to see if category fills up forcing my hand heh. Planning to enter >300 entry with continued Seas fanboy-dom, but not the kents (titan7+L12coax).

    Right now running these grs mid-tweet planars using minidsp, little no shelf on the epic's and mild pulldown shelf centered 6k since know from playing with simulations for a passive xover that some run up in response on the grs - havent even pulled out the microphone yet and intrigued by sound. Some past open baffle experiments were horrible in this room, prob because excessive mid range only echo's. Have passive xo worked out in models but had to see if worth clipping up to see.

  • @traw said:
    Anyway.... SDC2024, think they should allow GRS drivers in the 'dayton only' category.

    I had an idea for the PT2522c and thought about this, but assumed they wouldn't allow GRS in the Dayton category. I'm sure you could just send them an email and ask.

  • edited June 12

    Yeah and I keep wondering what the wavecor story is, was anxiously awaiting their "expected back 6/14" but being suspicious with the 'clearance' marking of items. Would suspect when people see metal stamped frames they think offering overpriced, but i was surprised by one of those offerings (w146paper). Had my eye on 8.5 paper sub(?)/woofer which solen does not carry. Where does Wavecor hale from?

    I'll prob ask about GRS just to know the answer, wonder if they not wanna broadcast grs nature. But prob still on other planned route

  • I'm entering the Anomalies in 300+, just for an answer...

  • What's the determent of padding down mid and tweet to match a bass driver? For specifics, have dual epic7 bass bin that should yield around 87-89db 1w but also have CSS SDX10's in 2cuft that believe are around 83db from what I can gather on interweb (should measure). Plan to integrate a midwoof-tweet and worry the latter, CSS which does even deeper bass, might be less efficient and have to damp the 2 way a lot. While my EE background says linear, the audiophoolery yanks the chains. What say you?

  • I've been told or read on more than one occasion that too much series resistance took the "life" out of a tweeter's sound. I've had instances myself with using 15 ohms in series that did not suffer "life" loss. However, I too have set a personal limit rule of thumb on values for series and parallel resistors, to which I can't always adhere.

    In terms of tweeter and midrange Lpads.....
    I try to keep parallel resistors above 1.5x the related driver impedance or higher. I try to avoid sending too much current through there after seeing the demise of resistors in builders' past. If possible, I will shift the parallel resistor value higher and increase the series R to compensate. I've seen lpads with 1 ohm across a tweeter, and it just makes my skin crawl even if there is series resistance out front of it.

    I also try to keep series resistance to a minimum and not go higher than 15 ohms.
    I know that Purifi/Lars say series resistance to a degree can lower HD, so up to a point is likely fine.
    In parallel notches (placed in series with driver, yes, Lars calls this a series notch which is incorrect via all other documentation of such an application I've come across), I have used 40 ohms before. However, this is targeting a very small bandwidth in most cases and therefore does not exceed my previous notions.

    In terms of value, I keep some 75, 100, and 150 ohm resistors on hand. This is to trim another resistor value to hear what the sound is like without changing the actual resistor in the circuit, especially for voicing a design.

    Not doctrine of course, and textbook wise, it might even be false. This is just my MO with regards to resistor usage.

  • I'm going to be the asshole and say use whatever it takes to get the job done, but always keep an eye on power dissipation and use appropriate wattage resistors. Just my opinion., and above all else have fun.

    WolfBilletSteve_Lee
  • I've read posts over at DIYAudio where certain people claim too large of a padding resistor will suck the life out of a tweeter, but I don't put much stock into that. I had to use a 15 ohm resistor in series (before the filter) to level match the drivers and the tweeters sounded great (my Viawave + SB15CAC project that was at Indy this Spring).

    WolfBillet
  • Additionally, my resistor methods stem mainly from the holistic xover methods I use, and "to do no harm", unless it's breakup or other such issues. Then feel free to kill them with fire!

  • @Wolf said:

    I know that Purifi/Lars say series resistance to a degree can lower HD, so up to a point is likely fine.

    I'm curious to learn the theory behind this. Is the series resistance somehow changing the reactance in the coil/motor?

  • The thought is that it adds electrical damping to the driver and damps the driver in the applied bandwidth. However, I'm not certain about this. I say this because it effectively reduces output like that of lowering the output from the preamp or amplifier. This means the HD will be lower magnitude at lower output, but is the reference to nominal output larger or equal to that of the driver at higher output or without the added resistance?

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