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Flush mounted K400/401?


Robbie010

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Has anyone done this and is there anything to be gained from flush mounting the horn from the outside of the motorboard??

 

I read a thread about the potential for the lip of the 3/4” ply to cause diffraction of the sound waves and it does seem counterintuitive to produce a exponential horn and then mount it in a recess....?

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If you move the midrange horn to the front of the front baffle, you also need to move the tweeter to the front of the front baffle, too.  This is to maintain whatever phase alignment of the tweeter/midrange that already exists. 

 

The bass bin--midrange alignment is 10x less sensitive to changes than the tweeter/midrange crossover (i.e., 1/10th the wavelengths at higher frequencies than at bass bin--to--midrange frequencies), so you don't really have to worry about that alignment.

 

Klipsch loudspeakers appear to be "phase aligned" at the crossover frequencies (but not time-aligned), so you don't really want to upset that alignment by moving one horn mouth but not the other farther forward toward the listener. 

 

If you choose to move the tweeter back to the back of the top hat (Khorn) or top of the loudspeaker (La Scala, whichever you have), then this is a good time to do it in order to time align the tweeter to the midrange horn.  You won't regret the improvement in soundstage, etc.  But you'll find that the time alignment goes in and out of phase within 1/4 inch of the correct relative placements of the tweeter to the midrange (K-55 driver).  In general, you need to move the stock tweeter back 24 inches relative to the midrange horn/driver by 24 inches in order to achieve time alignment.  That's equivalent to delaying the tweeter by 1.723 milliseconds:

 

LSII spectrogram showing 1.723 ms tweeter to midrange delay.jpg

 

Chris

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2 minutes ago, Chris A said:

If you move the midrange horn to the front of the front baffle, you also need to move the tweeter to the front of the front baffle, too.  This is to maintain whatever phase alignment of the tweeter/midrange that already exists. 

 

The bass bin--midrange alignment is 10x less sensitive to changes than the tweeter/midrange crossover (i.e., 1/10th the wavelengths at higher frequencies than at bass bin--to--midrange frequencies), so you don't really have to worry about that alignment.

 

Klipsch loudspeakers appear to be "phase aligned" at the crossover frequencies (but not time-aligned), so you don't really want to upset that alignment by moving one horn mouth but not the other farther forward toward the listener. 

 

If you choose to move the tweeter back to the back of the top hat (Khorn) or top of the loudspeaker (La Scala, whichever you have), then this is a good time to do it in order to time align the tweeter to the midrange horn.  You won't regret the improvement in soundstage, etc.  But you'll find that the time alignment goes in and out of phase within 1/4 inch of the correct relative placements of the tweeter to the midrange (K-55 driver).  In general, you need to move the stock tweeter back 24 inches relative to the midrange horn/driver by 24 inches in order to achieve time alignment.  That's equivalent to delaying the tweeter by 1.723 milliseconds:

 

LSII spectrogram showing 1.723 ms tweeter to midrange delay.jpg

 

Chris


Thanks.
 

One reason I ask is that the K-77 tweeters that I have came with the Z-brackets, which allow them to be flush mounted, so from your response it seems that flush mounting the mid-range horn is the right way to go.

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The tweeters are more sensitive to flush mounting than the squawker because of wavelength.  I lined the cabinet opening for the squawker with felt to mitigate the effect of that discontinuity.  I also did/do not have the tools or skills to make it attractive.   Since you are building, go ahead and flush mount the squawker from the front.  You might need to reinforce the screws if you route the front to make the horn flush. 

 

How is your build coming along? 

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I mounted the K400s from the front. I had to enlarge the opening to do that, of course. My plan is to make a piece to go on the front out of 1/2 or 3/8, to mount like a speaker grill, to make it appear flush. I haven't progresed that far yet. I will also veneer that.

 

 

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7 hours ago, JohnA said:

The tweeters are more sensitive to flush mounting than the squawker because of wavelength.  I lined the cabinet opening for the squawker with felt to mitigate the effect of that discontinuity.  I also did/do not have the tools or skills to make it attractive.   Since you are building, go ahead and flush mount the squawker from the front.  You might need to reinforce the screws if you route the front to make the horn flush. 

 

How is your build coming along? 


Thank you, I have the tools and gusto to have a go at flush mounting the horn but not necessarily the skill!! 😂

 

The build is coming along quite well, I should have the bass boxes done this week ready for sanding and staining, then I’ll move on to the high frequency cabinets. I decided I prefer the look of the split cabinet so went down that route, its a bit more work and a bit more wood but I may as well do it the way I want it. 

There have been a couple of oops moments, mainly due to the poor setup / misalignment of my new table saw but nothing that couldn’t be corrected..... or lived with! 

 

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2 hours ago, Randyh said:

if Gary gives you a compliment for this build , you are on the right track -


Thanks, they are looking pretty good for a first build!

 

2 hours ago, Randyh said:

is this birch  -----------will you keep these on the wood , or are you adding veneer

 

I was not planning to veneer them.

 

 I’ve been careful to choose birch ply with a nice grain / finish and as few imperfections as possible. However, I do have a number of stains to test and may use a matt poly finish. 

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When I first built my La Scala clones I had the  K401 horns just set on top of the bass bin with no baffle. Without digging through threads I remember there being a distinct edginess to the sound that was not good. Multiple members recommended a baffle to mount the horn to. This worked well. YMMV.

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1 hour ago, No.4 said:

When I first built my La Scala clones I had the  K401 horns just set on top of the bass bin with no baffle. Without digging through threads I remember there being a distinct edginess to the sound that was not good. Multiple members recommended a baffle to mount the horn to. This worked well. YMMV.


I will be building matching high frequency cabinets much like the La Scala II, to house the squarker, tweeter & crossovers. I have just routed out the recessed opening for the woofer binding post’s and the recess’ for the feet to sit in to:

 

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2 hours ago, JohnA said:

I had the front edges of mine covered with 3/4" x 3/4" solid cherry strips and stained to match. 

 

post-2142-13819247217712_thumb.jpgpost-2142-13819348975508_thumb.jpg

 

Some of the prettiest cabinets I've seen. Sure had us hooked when Josh and I came to visit you. That ws sure a different time...

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