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Chris A

Double Stack ESS AMT-1 with Wings--Possible Kit for Heritage

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1 hour ago, Thaddeus Smith said:

So here's one of my channels.. sub on the left and then LS bass bin/Heils on the right

 

image.thumb.png.7cbc2016966333a18280f97ad1d31948.png

 will

Very interesting how you have your system set up.  Hopefully @Chris A can take a minute and chime in on what is the PROPER way to set this up.  I will post an older picture (with much higher xover point) of how I set up my EQ to create a no-name xover.  This is an older screenshot, but I still use this technique.  Same goes for the LF and I just manually adjust the position of the attenuation to give me a flat SPL within +/- 2dB.

 

 

XoverSM.jpg

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If you're afraid that low frequency energy will affect your AMT-1s, you can easily put a first order high pass at a much lower frequency than the actual crossover frequency to attenuate those lower frequencies.  Note, though, that you'll have to be careful about where you put it so as not to introduce a significant phase lead in the AMT-1s at the acoustic crossover frequency (below is shown a second order high pass and low pass filter, and the total response of both the HP and LP portions in the plots):

 

1040961086_crossoverfilterSPLSPLphaseandgroupdelayresponse.png.fb8e0a81ea55869072f00f2250fbe5c9.png

 

Some of the phase lead introduced by the first order high pass filter can be "bent back out" by introducing a little time delay on the AMT-1 channel to compensate at the acoustic crossover frequency, but there will be a little wiggle in the phase and group delay curves relative to just using PEQs for the crossover, and I've found that the wiggle introduced is audible in at least the BMS 4592ND driver.  Once I took out the added 90 degrees of phase delay, the "magic" of the Jubilees on either side of the K-402-MEH center was transferred to the center loudspeaker, and the whole front of the room became a coherent sound source.  You've got to hear it...

 

One of the things that Tom Danley mentioned that caused the light bulb to go off for me was his comment that far out-of-band low frequency energy doesn't affect the HF driver because it doesn't respond to out-of-response-band low frequency energy. 

 

The same principle applies to low pass effects of drivers.  Well above the so-called "mass corner" of the driver, it doesn't respond to higher frequency energy fed it, and it effectively becomes the low pass filter itself (just like PWK did with Klipsch Heritage midrange drivers--the K-55s--in all of his crossovers, which, BTW, were typically first order filters). 

 

So Danley correctly pointed out that standard electrical crossover filters are not needed, only PEQs (notch filters) to attenuate the unneeded portions of the overlapping driver response.  By avoiding use of those standard ("named") electrical crossover filters, the phase shifts associated with them can also be avoided, and a much more engaging sound quality is produced by the entire loudspeaker, i.e., quasi-linear phase loudspeakers.  This is what I found by accident a little over a year ago: https://community.klipsch.com/index.php?/topic/182419-subconscious-auditory-effects-of-quasi-linear-phase-loudspeakers/page/3/&tab=comments#comment-2379562

 

Chris

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On 6/5/2020 at 6:50 PM, Rudy81 said:

The H frames turned out pretty good.  These monster drivers are ridiculously inexpensive, although limited in xmax. For listening room use, that should not be a problem. 

I have a couple of H frames for a single Eminence Alpha 15. I also have 2 pairs of Carver Platinums V III's. Limiting Xmax in a system is what reduces IM distortion, so kudos to YOU for creating bass and midbass with more CONE AREA. Open Baffle has some of the most detailed bass I've ever heard and it's right up there with bass horn in definition when done right. My Carvers have 4 12's, which is the same Surface Area as twin 18's, so I'm sure the IM distortion is just as low.

 

Since sound reproduction is ALL ILLUSION anyhow, the added 3D effect of DiPole radiation away from room corners is one of the best ILLUSIONS I've ever experienced........BUT, since I don't have the ROOM SPACE for it, I'm currently sticking to corner loaded horns.

 

You should be glad that you have the option in YOUR ROOM. Enjoy!!!

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By the way, in the MEH designs, the 90-degree phase shift of a first order electrical crossover is needed to invert the phase lead of the (acoustically coupled) lower frequency drivers that are physically mounted out in front of the apex-mounter compression driver by 90 degrees at the crossover frequency.  So you can use a first order filter between them to take out that physical 90 degrees of phase lead on each set of lower frequency drivers, or you can simple add a time delay equal to 90 degrees of phase lead on the lower frequency drivers to delay lower frequency drivers enough to match the phase of the next higher frequency drivers, which are physically located farther away from the listener.  Your choice (in an MEH). 

 

While this works for the woofers in the K-402-MEH (using a first order filter to delay them just enough), I found that it doesn't work for the dual diaphragms in the BMS 4592ND in the compression driver, because the lower frequency diaphragm is located farther away from the listener than the higher frequency diaphragm.  It requires the use of PEQs (only) with time delay on the HF diaphragm channel to flatten its phase response.

 

Chris

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@Chris A, so am I implementing your (Danley) concept incorrectly by attenuating the frequencies as I have done? When I looked at the unwrapped phase of the full spectrum SPL, I did not see any major turns.  Near the area where the drivers fade  out and fade in, there is an increase in the slope, but it is gradual and there are no other changes once it is fully on the other driver.

 

If I have done it incorrectly, perhaps you may have time to review the no name xover implementation? Many thanks as always.

XoverSM.jpg

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2 minutes ago, Rudy81 said:

@Chris A, so am I implementing your (Danley) concept incorrectly by attenuating the frequencies as I have done?

Not "incorrect", but you've got more phase growth (by about 90 degrees per order of crossover filters used) across the audible spectrum than if not using those "named" electrical crossover filters.

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7 minutes ago, Chris A said:

Not "incorrect", but you've got more phase growth (by about 90 degrees per order of crossover filters used) across the audible spectrum than if not using those "named" electrical crossover filters.

That's where I am confused.  I am not using ANY named crossover.  You can see that on the right side in the boxes LPF and HPF.....None is being used.

 

I created the attenuation you see by using a combination of a Low Shelf (PEQ1) and (PEQ2). The red line you see in the picture is another channel that does have a named filter.  I overlay the channels and simulate the named xover by playing around with PEQ1 and PEQ2.

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If you're not using (named or first order) crossover filters, instead using PEQs only (and not shelf filters), then you've got effectively zero phase growth across the crossover region(s). 

 

Chris

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1 minute ago, Chris A said:

If you're not using (named or first order) crossover filters, instead using PEQs only (and not shelf filters), then you've got effectively zero phase growth across the crossover region(s). 

 

Chris

Very good. I guess I am implementing the concept correctly.  I got confused when @Thaddeus Smith talked about sending a full signal to all drivers. 

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On 6/6/2020 at 3:29 PM, Rudy81 said:

So far, the double AMT stack with an OB low end is sounding superb.  No lack of bass at all with all these 18" drivers....frankly, that surprises me. 

It surprised me too, about 10 years ago, when I passed the Martin King information to my speaker builder friend (he subsequently gave me his single H frames and built taller OB's with 8 Alpha 15's per channel!!). 

 

It was the most detailed bass I ever heard this side of bass Horns!!

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1 hour ago, Rudy81 said:

Very good. I guess I am implementing the concept correctly.  I got confused when @Thaddeus Smith talked about sending a full signal to all drivers. 

 

In my dsp the crossover is set to "through," effectively sending full range signal to each channel. I've got peq filters in place, but nothing to cause a dramatic drop at any particular frequency to form a crossover. So we're both correct, but different? It sounds like I'm putting just a little more faith in Danleys theory that the driver's can't reproduce frequencies outside of their engineered band and therefore aren't at risk and you're creating peq shelves to ensure that.

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4 hours ago, Rudy81 said:

 

Here you go.  I put two triangular braces behind the double thickness baffle.  The top brace helps support the heavy twin stack. The bottom brace has the speakon connector installed.

 

thank you for sharing the design ,  the double thickness baffle for the twin , 18 inch woofers  adds the stiffness required for  the OB  concept -

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2 hours ago, ClaudeJ1 said:

It surprised me too, about 10 years ago, when I passed the Martin King information to my speaker builder friend (he subsequently gave me his single H frames and built taller OB's with 8 Alpha 15's per channel!!). 

 

It was the most detailed bass I ever heard this side of bass Horns!!

 

Several times I read MJ King's papers on his Goldwood H frame design.  I copied his frame dimensions and just added a second driver.  So far, it seems to work exceedingly well.  I'm amazed at how little the cones move when playing LF. More than enough bass for sure.

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1 hour ago, Thaddeus Smith said:

 

In my dsp the crossover is set to "through," effectively sending full range signal to each channel. I've got peq filters in place, but nothing to cause a dramatic drop at any particular frequency to form a crossover. So we're both correct, but different? It sounds like I'm putting just a little more faith in Danleys theory that the driver's can't reproduce frequencies outside of their engineered band and therefore aren't at risk and you're creating peq shelves to ensure that.

 

I don't know enough about the Danley theory to trust a full range signal going to the tweeters.  Makes one wonder why various named crossovers were developed to begin with.

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17 minutes ago, Rudy81 said:

 

Several times I read MJ King's papers on his Goldwood H frame design.  I copied his frame dimensions and just added a second driver.  So far, it seems to work exceedingly well.  I'm amazed at how little the cones move when playing LF. More than enough bass for sure.

It's calle "high Sd" with 2 motors in Thiele/Small Vernacular.

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For Claude...

 

could double stack ESS AMT-1 fit with Super MWMs? 

I mean instead of K-402 horns?

 

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17 hours ago, Rudy81 said:

I created the attenuation you see by using a combination of a Low Shelf (PEQ1) and (PEQ2).

 

 

17 hours ago, Chris A said:

If you're not using (named or first order) crossover filters, instead using PEQs only (and not shelf filters), then you've got effectively zero phase growth across the crossover region(s). 

 

 

@Rudy81 NOTE that Chris is saying and NOT shelf filters. I've switched to using only PEQs on mine. ie no shelf filters.

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40 minutes ago, rplace said:

 

 

 

 

@Rudy81 NOTE that Chris is saying and NOT shelf filters. I've switched to using only PEQs on mine. ie no shelf filters.

 

Thanks....PM inbound.

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@Thaddeus Smith, you were correct on this whole crossover thing....and I was wrong! Apologies. Thank you for bringing up the  issue so I can get my act together.

 

My Goldwood H frames have response up to 3kHz....so, do I simply use a series of PEQ filters to attenuate response?

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23 minutes ago, Rudy81 said:

@Thaddeus Smith, you were correct on this whole crossover thing....and I was wrong! Apologies. Thank you for bringing up the  issue so I can get my act together.

 

My Goldwood H frames have response up to 3kHz....so, do I simply use a series of PEQ filters to attenuate response?

 

Ha! I didn't care about being right, mostly just trying to grasp the concepts and it became clear that there was incongruence between what we walked through during my visit to your place and what I ultimately employed in my system.

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