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My ATC look-a-likes.

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badspeakerdesigner

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Just EQ APO.

Not sure how long this active setup will last, just randomly started getting a ton of noise from the crown xli-800 and the rca inputs, can hear my computer think. If only I had the funds to go balanced active or some hypex plate amps.
 
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badspeakerdesigner

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Not likely, vcad baffle sim and the edge show basically no change down there with driver placement.

Looks like one dc130 might be faulty, measures totally different above 1k than the other one. With the same active filter I'm getting totally different responses. Could maybe be a leak in the midrange enclosure but they also measure different outside of the box. Running a 40hz test tone on the midranges didn't reveal any audible leaks to me like it usually does.

I was thinking about the port and I may need to shorten it. It's a little hard to tell but I think I'm getting quite a bit of mid bass honk coming from the port on certain notes. Would shortening the port move these port resonances up in frequency or down?
 
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badspeakerdesigner

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So I guess these aren't really pit vipers anymore. I've since found running active xover to sound much better than the passive one so I don't think I'll use the passive xover at all. Time delays on the drivers is also pretty dang audible for everyone I've had compare.

I started swapping tweeters because the d27 just wasn't doing it for me. Ended up liking the nd25fw the best (go figure, waveguides yay). Seems to handle the volumes I use these at just fine, but I raised the xover to 3khz and made appropriate adjustments to the mid ranges response up there, gets kinda close to a rise in the driver, but hey parametric EQ. In room response is the best I've had so far, no more 100-150hz suck out! This is just running the xover filters, no corrective room EQ applied yet. Taken from about 10ft away.

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badspeakerdesigner

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Still kind of undecided on whether I like the BMR or the dc130 more, they both have pro's and cons. I downloaded fusion 360 to learn and maybe make a little mount for the BMR driver, this one has a minor waveguide arch to it. No idea if this is a good idea for the driver or not. I may make it very shallow, almost flat, we'll see. This is more a fusion360 learning process for me atm. I had to get help with this model... this programs kinda hard.
 

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badspeakerdesigner

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So I think I have a resonance but I'm not sure if it's the room or the speaker. Something in the mid bass just honks out, I plugged the ports but it's still there, added different amounts of dampening and I still hear it. I trimmed the ports a bit from 13" to 10" which didn't change tuning freq too much, it's at 30hz now, and raised the first port resonance up to ~700hz, I think I still hear it. REW doesn't seem to show any sort of bad decay in the woofer or ports. Hard to tell if it's the room just walking around. Might have to share some data to figure this out.
 
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badspeakerdesigner

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Low end of the midrange?

There's a resonance around 250hz that seems to show up in most measurements. I did fix a lot of mid range unhappiness by take away a good chunk of the woofers response around 800hz-1k, sounds clearer now. I notice the side walls kinda "sing" a lot, can feel that 250hz resonance, so I might add some more braces.
 
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badspeakerdesigner

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I think my issue might be related to this.


I've got some 2" and 4" mineral wool I'll play with. Current dampening is probably not adequate at all, just poly fill mostly. No way to measure impedence atm though.
 
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badspeakerdesigner

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I lined a cabinet with 2" oc 703, and filled it with a bunch of different stuff, lots of poly fill and a pillow, along with a sheet of 2" memory foam. Just trying everything. Putting all of that in seems to have entirely killed the resonance I had. Sounds quite a bit different now. I only did one so far, lots of work getting the insulation in and covering it so fibers don't go everywhere. Seems the stuffing around the bottom has a good bit of impact vs. other areas.

I don't know if it's possible to over stuff a cabinet. I got some thick dowels to add bracing in a few places. I'm thinking I should've made the cabinet a bit deeper.
 
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badspeakerdesigner

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Made a little impedance measurement thingy, I see a small blip where I hear a resonance. I'm not sure if my measurement is right here, first time I've done it. I can toss some EQ on but it takes a lot to get it down, then it feels like some important energy was lost and the music is dull. It really ruins an otherwise good speaker.

I took out the memory foam as I didn't like how it sounded, also took out the pillow as my impedance measurement showed no change on that blip. Is my cabinet doomed? Internal dimensions are 13x14x28.5"

impedence.png
 
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badspeakerdesigner

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I thought I'd chime in and share some info for anyone who's looked at this project and may wish to do something similar. I no longer have the speakers hooked up and drivers have been pulled. I ran into a few major issues that I didn't account for and had to experience for myself. The above impedance graph can be ignored, I was still figuring out impedance measurements.

1. Either the cabinets vertical dimensions or the room caused a big resonance in the upper bass, approx 178hz. The port showed a resonance here and plugging it didn't seem to fix it for the most part. EQ helped but it kinda seemed like removing that energy resulted in a thin sound. I tried dampening and adding extensive bracing to dampen what I'd consider a fairly lively cabinet. Nothing really helped. None of my other speakers exhibited this problem with the same placement.

2. These things just image pretty poorly. My initial impressions were that of good imaging, but that was really a honeymoon phase thing I feel. I think this is largely in part of the wide baffle. I've heard a lot of conflicting opinions on baffle width and it's relationship with imaging and dispersion. I did try a waveguided and non-waveguided tweeter with differeing xover points and was disappointed with both. I think this is really something you just need to hear for yourself to decide. Comparatively all my narrow baffle speakers image quite well with a depth that these big speakers just lack. These big speakers call more attention to themselves and don't really 'disappear' at all. A lot of people I talk to argue that small baffle speakers are largely more common due to manufacturer constraints (easy to ship small speaker, fits in most homes better) but I'd argue when executed well, they just sound better. I'd wager there is a reason companies making state of the art speakers are keeping the baffle widths small.

3. These things are super heavy and I can't move them by myself. This makes any modification and analysis super hard. I pulled a back muscle moving them :(

4. Active filtering for three ways kinda sucks. It's just too expensive for me to do it to degree that would satisfy me. I'm currently using my onboard sound card but the jacks are very loose, one was pulled out by my cats and sent nice hum to the mid range (tweeter would've died probably if suffered the same fate). It's all unbalanced and I don't care for that, I have a lot of pro audio and musician experience so it's XLR or TRS or bust IMO. RCA and 3.5mm are junk connectors to me.

This was a ton of work just to learn what I don't like, but hey at least I know. There were some positives, like having effectively two subs in front of me, which let me put my two subwoofers behind me and enable a sort of multisub setup. I can tell you right now if you want even bass in your room, just go multisub. Forget wasting money on 'bass traps' and such, this is the most even low end I've ever had and it's great. Even without DSP just adding subs evened things out a ton. It's kinda crazy to just walk around the room and hear the same bass everywhere.

My current plan is to save the 12" woofers and build sub boxes for them, continuing to use them in a multisub configuration. I'd like to keep doing diy speakers, but man it's getting harder and harder to convince myself it's worth it. If you've got high standards it seems quite hard to make something better than what you can buy. If I dive in again, it will be a coaxial driver (not many good ones for DIY) on a thin baffle. KEF LS60 paper is going to be good reading for me. Even so it will be hard for me to justify not just grabbing a pair of KEF floor speakers.
 
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jamescarter1982

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you should defo keep going . maybe make a slim medium sized 2way standmount cabinet and 2 subs with those dayton 12s .it seems you can get some top end drivers for 150quid each or so . I'm not sure what was wrong with your speaker to make that resonance but I think you made an awesome job of it
 
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badspeakerdesigner

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A slim coaxial using a sica driver is where my brain is currently going. I will certainly be building some sub enclosures for the 12's.

I think there is a point at which one needs to take a step back and ask themselves if what they're doing is getting in the way of the music and in a lot of cases, the other important aspects of your life. I hit a point where I said "this is just too much effort, I just want to listen to music".

I'm going to be throwing some hard science at whatever my next build is, because I ignored a lot of things I already know to make these just to have some cool looking ATC style speakers. Luckily there isn't a whole lot of money into these cabinets, the wood is pretty cheap junky ply.
 

jamescarter1982

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I like the atc style though . having heard some scm50s I was impressed by the smooth dispersion and assumed that's down to the mid dome . I'm making some decent sised similar style speakers atm
25mm ply screwd and glued cement board on the inside stuck on with bitumen paint and painted over with the same stuff I'm gunna just line the outside with some thin mdf and maybe some veneer maybe looking at your build gave me a bit of push to get on with them
 
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badspeakerdesigner

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Have you heard genelec or neumann speakers? I generally find those to offer the best imaging I've heard so far.

I haven't heard any ATC in real life but I can't imagine they've gotten around the physics of the sharp baffle edges. The mid dome being no longer sold hurts prospective builds, and I don't have interest in drivers with what I'd consider crazy prices like bliesma domes. Hivi has a new 3" but QC seems bad.
 

jamescarter1982

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no not genelc or nueman always wanted to though .heard atc and quite a few dynaudio and some quested 2108 I think based on a volt midbass . the dynaudio bm15a I have image amazingly but the best sound I've heard is some vintage kef references tied with some avi nuneutrons that just sounded lovely wherever you put them . I think the waveguide on the atc mid dome dies counter diffraction of the wide cabinet by controlling the sound as it leave the waveguide . hope that made sense . I've just got some dynaudio d76 domes from some kh410 monitors for a good price but before I picked these up I was looking at the tangband 3inch dome . that seems to be the one to get atm
 
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badspeakerdesigner

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I'd suggest trying to listen to some controlled dispersion stuff first. Also, at the design phase there are issues one may not know of until they run into them, for instance the baffle width of these really wrecks the tweeters response, you aren't given a response that is easy to work with. Active can make it easy to get things nice on axis but once you go off it's just problems.
 
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badspeakerdesigner

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Actually I think I'll just make some subs with these woofer and hop out of DIY. I'm not sure I can stomach the crossover design process or another complicated active xover setup. I'd love to just get back to writing and listening to music and not worry about the speakers. Too bad I can't really sell any of my drivers because they're all on the low end of cost and shipping outweighs the effort and cost. It was fun to learn and try, but ultimately I can't really make a better speaker than you can buy.
 

jamescarter1982

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half the speakers put out there by companies are just thrown together with glaring faults I bey you could defo make something better than you could buy maybe not on the budget end but mid to high definitely. there's someone I think on here with a thread called faltter than flat who's just absolutely smashed it two decent drivers bit of dsp
 
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