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Dallas II build - Phase shift?
Dallas II build - Phase shift?
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Old 19th July 2019, 03:11 PM   #11
Scottmoose is offline Scottmoose  United Kingdom
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A is least compromised in terms of position relative to the main driver.
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Old 19th July 2019, 03:21 PM   #12
WayneAudio is offline WayneAudio  United Kingdom
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Originally Posted by Scottmoose View Post
A is least compromised in terms of position relative to the main driver.
Agreed re point-to-point distance between the two, but the Youtube video I shared gives a good case for positions B or D so as to give a good 'ambience' and not cancel out / clash with the frequencies generated by the full range driver (Fostex FE208ez).

I threw C in there as a potentially even better version of B.

As a reminder, it's the Fostex T90a super tweeter I'd be using with (probably) a 1.0 - 1.5uf cap.

YouTube

Last edited by WayneAudio; 19th July 2019 at 03:38 PM.
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Old 19th July 2019, 04:04 PM   #13
Scottmoose is offline Scottmoose  United Kingdom
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I defer to your superior knowledge.
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Old 19th July 2019, 04:17 PM   #14
WayneAudio is offline WayneAudio  United Kingdom
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Originally Posted by Scottmoose View Post
I defer to your superior knowledge.
I very much doubt I do have superior knowledge, mate! I'm a novice.

I'm simply going by what others have implied in this thread (and another I started a couple of years ago) about placing and / or pointing the tweeter in different places / directions. Plus the YouTube video which seemed to make sense to me.

I value your opinion so thanks for suggesting position A and giving your reason.

Do you have a view on the other positions?

Thanks again.
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Old 19th July 2019, 05:21 PM   #15
planet10 is offline planet10  Canada
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Dallas II build - Phase shift?
I like A, but i suspect that you could get the tweeter even closer than you have drawn.

The video is useful. Do note that a half-inch is a huge amount one should be moving it by mm. And the placement of the microphone makes a huge difference. You can take the general ideas but in the end there are huge gotchas -- you have to listen to it and decide what works for you. (this guy works closely w Danny Richie and the ideas are very similar to an essay he posted on Audio Circle).

The dispersion of the tweeters he is using are way different than yours, crossing high you really want dispersion similar to the FR at the XO.

With the FE208e∑ you are talking about an XO an octave lower.

The issues with the overlap with just a cap on the tweeter can be at least partially e;iminated by increasin gthe slopes of the XO. Here is a speculative XO that i did in a thot experiement for the FE207 the same concepts applys for you.

Dallas II build - Phase shift?-fe207-ft17-xo-topx-gif

This puts secound order on the T and adds a 1st order to the FR, so much less overlap, and the series XO means that the 2 drivers track each other somewhat. A series XO may be a bit trickier to implement.

dave
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File Type: gif FE207-FT17-XO-topX.gif (13.3 KB, 73 views)
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Old 20th July 2019, 07:21 PM   #16
DaveCan is offline DaveCan  Canada
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OP, if you're a complete novice as you say, then why not make the cab to spec instead of adding two drivers not designed for the Dallas, and now a crossover as well? Dunno, don't make no sense to me...
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Old 20th July 2019, 07:28 PM   #17
WayneAudio is offline WayneAudio  United Kingdom
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Originally Posted by DaveCan View Post
OP, if you're a complete novice as you say, then why not make the cab to spec instead of adding two drivers not designed for the Dallas, and now a crossover as well? Dunno, don't make no sense to me...
Just because I'm a novice, doesn't mean I can't have desire or ambition, pal. When did I say anything about a crossover as well?

Last edited by WayneAudio; 20th July 2019 at 07:30 PM.
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Old 20th July 2019, 07:37 PM   #18
DaveCan is offline DaveCan  Canada
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That's fine have at it... But maybe it would have been nice to build it to spec as designed by Ron, then once you've actually heard it as designed which by your choice you never will, then maybe look for some tweaks to it, um pal.... :/
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Old 20th July 2019, 08:15 PM   #19
WayneAudio is offline WayneAudio  United Kingdom
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Originally Posted by DaveCan View Post
That's fine have at it... But maybe it would have been nice to build it to spec as designed by Ron, then once you've actually heard it as designed which by your choice you never will, then maybe look for some tweaks to it, um pal.... :/

Ever tried being constructive instead of coming across as a sarcastic ****? Distinct difference between everyone else who's replied to me, and you.

Maybe you just bypassed the keen novice stage and jumped straight to a know it all expert.
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Old 20th July 2019, 08:27 PM   #20
DaveCan is offline DaveCan  Canada
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I responded to your derogatory bs by calling me "pal" is all, which was uncalled for. And if you can read maybe you should look it all over again, as you stated yourself in your opening post that you don't know what you're doing. So all I said and asked is why are you not building the cab to spec rather than going off on your own design tangent?

So if I designed a cabinet that was specific to a driver and it worked well, then you'd come along after never hearing that design and add your own drivers and try to make all your own modifications to a design you've never heard nor understand. Make sense?, or am I still the bad guy here?
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