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A K-402-Based Full-Range Multiple-Entry Horn


Chris A

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Hi
 
I was wondering what you refer to in regard to wiring between your two woofers and the Icepower 125asx2BTL?
 
 
So I take it, that you had your two woofers wired in series and then driven BTL.
 
I don´t know how well you are into your Icepower-amp, so excuse me if i tell you something you already know. I have attached the manual for the Icepower 125asx2.
 
On page 9 there are some Power Specifications, but it doesn´t seem to indicate, that there should be much difference in output-power whether driven with two channels SE and 4 ohm or one channel BTL and 8 ohm!?
 
An other thing that I noticed when studying the manual is, that there is a pin on the signal connector from the DSP-board to the ICEPOWER-board that says "BTL Sync". Page 6. When it is activated it synchronizes the switching-frequencies of the two amp-channels. Page 12. I don´t know how much DIY your amps are, but maybe that is an issue when driven in BTL without synchronization? On my MiniDSP plateamps, the software/dsp-board takes care of that.
 
 
(I own six of the MiniDSP PWR-ICE-125 plate-amps, and have studied the the manual for the Icepower  125asx2, to figure out how I can substitute the Icepower with a small class A amp. There is a manual for the Icepower 125asx2 on the MiniDSP homepage.)
 
Steffen
 
ICEpower125ASX2_Datasheet_1_9 (3).pdf
I was running in BTL mode driving 2 4ohm woofers which was presenting a 8ohm load to the amp (I never drove them in SE mode...I only use XLRs). I added a 2nd amp and rewired my woofers so each woofer was now powered by a single amp in BTL mode. Now if you look at my REW graph you will see how much my bass has increased by adding an additional amp and powering each woofer individually. I am tninking it has to do with the impedance load, and power output the amp is seeing by driving 2 4 ohm woofers versus 2 amps driving a 4ohm load each. I have the BTL pin as per the manual too.

I find it strange in the way they are showing their power output too. I think they flipped the 8ohm and 4ohm spec on the one spot as they show way more power into 8ohm than 4ohm. The amp is spec'd at only 70w into 8ohms at one spec and 200 at another. For 120v it is spec'd at 370w into 4ohm BTL...with no rating at all at 8ohm. I am assuming 8ohm would be 1/2 that and since it would be driving 2 speakers...wouldn't it be giving 1/2 of that 8ohm to each woofer?

Sent from my SM-T830 using Tapatalk



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Good news, I have the bass back up to where it was and if you look at the was before we added the 2nd amp... I def got a nice improvement in bass by powering each woofer by its own Icepower amp...also it appears the large peak and dip when i used 4" of Roxul all around instead of 2" on the side, floor and behind the mic actually caused the difference. 

Right channel 11 1 old vs new.png

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On 5/13/2020 at 6:58 AM, Chris A said:

By the way, the SH-96 horn is 26.5x45 inches and I assume about 17 inches deep (25 inches for the entire loudspeaker box).  I did a little fudging within Bill Waslo's Synergy Calc spreadsheet to approximate the outside dimensions of a dual-flare (straight sided Danley Synergy style) horn that would fit into an approximate box of the same dimensions without the mouth flange of the K-402, which you will see below.  (Note that I haven't built this horn or tested it yet.)

 

1718312032_SynergyCalcapproxforK-402.thumb.JPG.259b1d82066a72055e74438a68df1c60.JPG

 

 

 

1676798769_SynergyCalcapproxforK-402cutdimensions.thumb.JPG.66d4942c9b33221495a4a713789e8e5e.JPG

 

 

1372955885_SynergyCalcapproxforK-402mountingpiece.thumb.JPG.fd9efcfb6ec4e644de591bec3dac6c15.JPG

 

Chris

Hello. I don't have and can't really get k402.  Is this what you think is the best option?  Is it worth going even lower than 200hz with a bigger horn?  would be using the 2 15s and 2" compression driver Thanks 

 

I'm very familiar with sh50 and setting up MEH speakers. As well the principles of how they work and what makes them magical. I love what you have done on this full range topic, thanks for that.

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Hi Tweakin

 

7 hours ago, tweakin said:

Is it worth going even lower than 200hz with a bigger horn?

 

I did ask Chris the same question some time ago in this thread, and Chris did answer it back then. You have to go back and find it your self, I have lost track of where it is, its in the last third I guess.

 

I have decided to build my horns about 53 inches wide, as that is as big as I can accommodate in my living-room. It´s actually about where Chris estimates the (meaningful) limit to be, 60 inches I think he mentioned. Meaningful in respect to your/most living-rooms Schröder-frequency. Directivity-control makes sense as long as the reflections in the room behave like billiard balls, and that is the case above Schröder-frequency, below that frequency room modes (standing waves) are dominating. That is how I understood Chris in regard to size.

 

8 hours ago, tweakin said:

Is this what you think is the best option?

 

I have followed this for some time now, and there doesn´t seem to be a commercially available horn alternative to the K402, so building a horn based on Bill Waslo´s spreadsheet is the second best option as I see it.

 

I have decided to build my horns in two sections. The primary horn (first expansion) with all the drivers, and a second section (second expansion) for the outer flare/second flare. In that way I can get my horns through the doors in my house, and it will be less heavy to transport! And I can experiment in steps, so that I can start with straight (second) flares and later build som tractrix-like flares. 

 

I hope that helps.

 

Steffen

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  • 1 month later...
On 11/12/2021 at 2:06 AM, Supersteff said:

Hi Tweakin

 

 

I did ask Chris the same question some time ago in this thread, and Chris did answer it back then. You have to go back and find it your self, I have lost track of where it is, its in the last third I guess.

 

I have decided to build my horns about 53 inches wide, as that is as big as I can accommodate in my living-room. It´s actually about where Chris estimates the (meaningful) limit to be, 60 inches I think he mentioned. Meaningful in respect to your/most living-rooms Schröder-frequency. Directivity-control makes sense as long as the reflections in the room behave like billiard balls, and that is the case above Schröder-frequency, below that frequency room modes (standing waves) are dominating. That is how I understood Chris in regard to size.

 

 

I have followed this for some time now, and there doesn´t seem to be a commercially available horn alternative to the K402, so building a horn based on Bill Waslo´s spreadsheet is the second best option as I see it.

 

I have decided to build my horns in two sections. The primary horn (first expansion) with all the drivers, and a second section (second expansion) for the outer flare/second flare. In that way I can get my horns through the doors in my house, and it will be less heavy to transport! And I can experiment in steps, so that I can start with straight (second) flares and later build som tractrix-like flares. 

 

I hope that helps.

 

Steffen

How do you plan on attaching the flare... I ask this because I am thinking of extending mine to give me the flare all the way to the stock horns flat front outside edge. The only think I could think of was to make a picture frame and route the inside to match the flare, but then where and how do I attach it temporarily? 

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Hi Ron

 

Sorry, did not sea your post until now.

 

I must admit that I do not have a finished plan for the attachment of the second flare yet, and I am still far from building a horn. I am stil in the planning and preparation, trying to figure out where to start.

 

But if I do understand your question right, you want to extend the tractrix-curve of the second flare all the way out to 90 degrees, and by so extending the whole horn.

 

I think the idea makes sense

On 12/30/2021 at 6:50 PM, NBPK402 said:

to make a picture frame and route the inside to match the flare

You could make two frames, an outer one extending the tractrix-curve, and an other one screwed on from the back, clamping the K402 horn between them? Does that make sense?

 

Happy new year 🙂

 

Steffen

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On 1/1/2022 at 9:39 AM, Supersteff said:

Hi Ron

 

Sorry, did not sea your post until now.

 

I must admit that I do not have a finished plan for the attachment of the second flare yet, and I am still far from building a horn. I am stil in the planning and preparation, trying to figure out where to start.

 

But if I do understand your question right, you want to extend the tractrix-curve of the second flare all the way out to 90 degrees, and by so extending the whole horn.

 

I think the idea makes sense

You could make two frames, an outer one extending the tractrix-curve, and an other one screwed on from the back, clamping the K402 horn between them? Does that make sense?

 

Happy new year 🙂

 

Steffen

That is a good idea!

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