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New Project: Chop top LS with Double Stack ESS AMT-1

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1 minute ago, rockhound said:

Looking good!


It's getting there. I'll have a few spots of filling + sanding to do before paint. I like to knock projects out in a day/weekend, so this is certainly stretching my patience as I try not rush through it all.


I also worked on fresh internal wiring with speakon connectors, cleaned up the factory bottom screws (a bunch had random gunk in the philips slots), and rewiring my monoprice XLR interconnects to have a phoenix connector on one end, etc. I didn't reckon everyone wanted photos of those random bits.

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Went back outside for a bit and pre-drilled mounting holes on the new bottom panels, along with sorting out how I'll mount the big ol' rubber feet. I'm hoping to be sanding and painting by next weekend. digital XO will be here by that point and I can finish getting it wired into place and talking on the network.


then it's just letting the paint dry, moving it all inside, mounting the drivers back inside, and running new lengths of cables to all the drivers. i'm hoping to be burning in my ESS drivers with some basic crossovers within about two weeks.


then rudy and I will make x-wings as time permits, prep-paint-dry, and then I attack proper measurements and applying ChrisA's method of flat phase crossovers. I may wait until after April's learning session for that part.

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I'm impatient and figured after 6 hours the panels I glued this morning would be good to trim - and they were. We had beautiful weather this weekend so i wanted to try and get everything glued and set before Temps dip again. So, final panels are new glued and strapped and I'll trim those tomorrow.


Every panel got the Jackson pollack treatment before being strapped up to the cabinet.



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For posterity's sake I wanted to detail the following tidbits of info. To fund this project I've sold:


OEM k401 horns

CT-120 tweeters, A-55G mids, DeanG type A crossovers with Jupiter caps

QSC PLX 1202 amp (used for subs)

ATI AT1505 (used for mains)

Spare file server

My least used camera lens


And that has covered all of my equipment costs:


Yamaha SP2060

3x Lab.Gruppen E 4:2 amps

4 of the ESS heil drivers

Balanced interconnects

Misc. cabinet hardware such as feet, speakon connectors, barrier strips, hookup wire, etc.


I borrowed the router and some bar clamps. I'll be taking advantage of Rudy's precision woodshop (and his experience) to ensure the wing assemblies come out clean and tidy.


I lost money on most of the items I sold in order to move them faster, but I was able to find some good deals on the things I purchased - so I broke even in that regard. So far, all I've purchased truly out of pocket has been the new plywood and stuff like glue, straps, router bit, sand paper, etc. I'll need to purchase some more plywood for the HF wing assemblies.

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Panels are all done, including the bottoms (not pictured).


Now to do some filling and sanding before paint. I've got a couple of rookie mistakes that I'm going to leave as-is, but otherwise they've come out pretty cleanly and don't need too much makeup art.


They are indeed heavy, but not too bad. Fortunately I'm only moving them a couple of times in the next decade. Now that I'm going active xo and already have competent subs, any speaker changes will likely be in the HF area.



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My Yamaha is due to arrive tomorrow, so I've been playing with the software to start familiarizing myself. I'm using one of the built-in scenes to just get sound through the various drivers and landed on this one. I guess a 3x configuration would be just as effective since I'm reducing down to two channel, feeding the signal from my L+R Mains pre-outs and then on to my 2x subs, 2x LS bass bins, and 2x double stack of Heil drivers.


Rudy gave me a down and dirty on mic placement and measurement procedure for figuring out phase and delays between the HF and LF, but then where do I need to place the mic when working out their delay in relation to my folded horn subs?


I notice also that the unit only processes down to 20Hz, so rather than set a HPF on the TH-SPUD clones, I just set them as passthrough and I guess they'll just naturally roll off with the limits of the processor? The last 12+ years my procedure has been: plug into sub pre out, run Audyssey, enjoy. When I moved up to passive horn subs I never added external DSP and just let my AVR do it's thing so I'm scrambling to wrap my head around how I take over for what Audyssey has just done automatically behind the curtains.





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My last piece of electronics, the yamaha DSP, arrived today. I've got it factory reset, firmware updated, racked, and communicating with the yamaha DME designer software. woot.


i've got 4 of the outputs wired up to the two amps not currently being used. Will finish wiring up the third amp and tie it in with the AVR once I get bass bins back in the house. X wings are in progress.


Then it's stuff like HEIL driver burn-in (and unboxing), gain matching, REW setup, etc.

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On 2/19/2020 at 3:50 PM, Thaddeus Smith said:

Rudy gave me a down and dirty on mic placement and measurement procedure for figuring out phase and delays between the HF and LF, but then where do I need to place the mic when working out their delay in relation to my folded horn subs?

I've found that for purposes of achieving time alignment with subs,  you can leave the microphone in the same place (1m in front) since the time alignment is very insensitive to distance and dialed-in time delays at 30-60 Hz. 


For EQing the subs to flat SPL response, then you probably need to move the microphone to the main listening position.  This is the only time that you can really measure from the listening position.


I actually take these measurements at the 1m position from the front loudspeakers however, because I'm trying to adjust the sub's minimum phase response, not trying to boost room cancellations due to 1/4 wave reflections from the room's boundaries.  In general, you can shave off peaking response, but not boost the sharp troughs in SPL response. 


You can look at the excess group delay plot to see if your trying to boost or cut non-minimum phase response.  The areas where there is significant non-minimum phase (all pass) response is where the excess group delay curve isn't flat (and that's usually most of the measured response below 60 Hz). 


Below you'll see a combined response plot of my right Jubilee with both subs, taken 1m in front of the Jubilee on-axis.  The green trace is SPL response, the purple trace is phase, and the white trace is excess phase:




But when we get to the excess group delay (rate of change of phase response with respect to frequency) you see a huge amount of non-minimum phase response.  This plot had to be zoomed way out to see the total group delay indicating that almost all of the the response in-room is dealing with room boundary reflections:





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