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Multi-Way Conventional loudspeakers with crossovers

Couple quick questions re my project
Couple quick questions re my project
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Old 5th February 2020, 10:31 PM   #11
pdq2 is offline pdq2  United States
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Originally Posted by RobWells View Post
Is this all being measured / setup in room at seating ? If yes then try moving the speakers outdoors as far away from walls / boundaries as possible and redo it all to measure flat. Then put them back in the room and have a listen.

The last graph posted shows no subwoofer at all. It hasn't been high passed by mistake or left switched off or something ?

Rob.
Yup, in the room where it will live. And I appreciate your suggestion, but part of it is built-in, so I canít really move it at this point.

And I donít know what the deal is with the low response on the last graph, but I agree - I need to check my wiring again.
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Old 5th February 2020, 10:48 PM   #12
RobWells is offline RobWells  United Kingdom
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In that case you need to set up the system to have a room curve. Google the JBL synthesis curve for a start and see if that improves things. Flat in room sounds thin / lacking body / no slam etc in my experience.

Have a read of Floyd Tooles book Sound Reproduction (there might be some pdf papers available on line) It will explain better than I can why a speaker should not measure flat in room.

Read this


Rob.

Last edited by RobWells; 5th February 2020 at 10:55 PM.
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Old 6th February 2020, 03:14 PM   #13
pdq2 is offline pdq2  United States
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Rob,

Will do - thanks. (Unfortunately, your link doesn’t work for me - “not found”)

And I appreciate the earlier comment about checking the phase of each of the drivers - I will check that too. And finally, I will look again at the discrepancy in the sub woofer response.

Got out-of-town visitors right now, but when they leave, I’ll have some work to do and come back and report here.
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Old 6th February 2020, 04:10 PM   #14
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Not sure if this is the one Rob linked to, but this is the one I remember: http://www.wghwoodworking.com/audio/...production.pdf

GM
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Old 6th February 2020, 07:29 PM   #15
RobWells is offline RobWells  United Kingdom
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Sorry the link I posted was working for me, it's the PDF here:

AES E-Library >> The Measurement and Calibration of Sound Reproducing Systems

Hopefully that will work now.

Rob.
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Old 6th February 2020, 10:48 PM   #16
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Thanks! Wasn't aware of this one.

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Old 13th February 2020, 03:33 PM   #17
pdq2 is offline pdq2  United States
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Just a quick update - turns out I _did_have one driver out of phase, and things sounded better after correction, but I’m still not quite happy with it and I’m thinking there may be significant time alignment issues with the larger horns. (The low-midrange horn is around 4.5 feet long, and the subwoofer more like 12 feet - my home theater receiver may be compensating for the latter (it has Audessy) but not for the low-midrange horn).

The low end FFT response curve was a problem with the iPad I was using, I think - Apple sets up a strong low-bass rolloff/cutoff in iPhones and iPads, and once I made sure that the app was using the Dayton imm-6 mic and its cal file, the low end reappeared in my FFT tracings.

I’m now considering getting a MiniDSP and uMic and using the REW software. It’s about $200 total, but it would replace the equalizer, external crossover, and the imm-6 I’m using now and I could probably get half of that back reselling the older stuff on eBay.

Oh well, it’s a hobby, right?
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Old 14th February 2020, 09:25 AM   #18
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Are the mouths or drivers aligned? XO point/slope?

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Old 14th February 2020, 02:00 PM   #19
cspieker is offline cspieker  United States
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Umik, minidsp, REW. Great idea, exactly what I use and they are all very easy to use. Also keep in mind that with horns, you will want a room curve at listening position that leans down even more in the treble than a standard room curve. I take 6 measurements in the listening position moving the mic several inches each time. Then click the "all spl" tab and average them. You'll want something like a flat response up to 1k, then it will slant downwards towards 20k, ending up down maybe 15db at 20k.
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