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Chris A

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

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I'm not familiar with the Lynx Aurora 8.  I don't know if it has the necessary interfaces and functionality of a DSP crossover ("loudspeaker processor").  A quick google of those keywords didn't yield very much.  If you've used the Aurora 8 as a DSP crossover in the past, here's what you'll need in terms of functionality for a K-402-MEH type (full-range) multiple entry horn:

 

1) at least two input channels and four output channels, preferably with balanced connections (XLR or Euro/Phoenix connectors will work)

2) at least 5 input channel PEQs (parametric) biquads and 6 output channel (parametric) biquads

3) digital delay on the output channels with resolution to 0.1 ms or less

4) gain control on all channels, and a mixer that can assign input channels to output channels

5) crossover filters, i.e. ,Butterworth, Linkwitz-Riley, Bessel, etc., or enough extra output channel PEQs to suffice in place of the crossover filters

6) low noise levels in terms of its connections and processor noise

 

 I'd also recommend 96 kHz internal sampling rate over 48 kHz (which the Lynx seems to have--even up to 192 kHz internal sampling from preliminary perusal). 

 

If the Lynx doesn't do the job, you could also use a miniDSP 2x4 HD ($205 USD) or a 4x10 HD ($545 USD) with double the I/O capability and digital input/balanced connections. These are about half price vis-à-vis the Xilicas.  Note that the Xilicas have lower noise levels generally but if you've got a way to control the connection noise levels and can do proper gain-staging, then no worries. 

 

Chris

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58 minutes ago, Chris A said:

I'm not familiar with the Lynx Aurora 8.  I don't know if it has the necessary interfaces and functionality of a DSP crossover ("loudspeaker processor"). 

 

As far as I can tell, the Aurora is just an A/D and D/A converter with some digital I/O and internal mixer. No processing capability. Some of the Lynx products have USB connections that will allow you to process the signals in a computer via ASIO, but this doesn't appear to be one of them.

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Posted (edited)

Thank you Chris and Edgar

 

As far as I can tell, Aurora8 will do Analog/Digital IO, routing, levels but that's about it, no EQ. I'll have to look at the manual again.

I would like to use it if possible. I'll have to search if there is a XO/EQ software solution that would work with it. Let me know if you guys know of one.

If not I'll have to look at miniDSP or Xilica...

Edited by Jesal

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Right now... I use Jriver>>Audiolense>>Aurora8>> 6Channel Amp >> 3 Way speakers.

Link>> Audiolense does automatic delays, XO, FR correction...

 

Chris, I don't know if your adjustments can be done in Jriver or Audiolense.

I think it can be done with my current gears, but I'm not 100% sure.

I have some research and more reading to do...

 

FYI: I'm trying to see if I can improve on and replace my SH50. I already have BMS 4592NDs and 15" woofers. Still trying to source out the K402s if I can't, I'll have to DIY the horns.

 

 

 

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9 hours ago, Jesal said:

Right now... I use Jriver>>Audiolense>>Aurora8>> 6Channel Amp >> 3 Way speakers.

Link>> Audiolense does automatic delays, XO, FR correction...

 

Chris, I don't know if your adjustments can be done in Jriver or Audiolense.

I think it can be done with my current gears, but I'm not 100% sure.

I have some research and more reading to do...

 

If the PC running Audiolense has enough computing horsepower (which it appears to have), it looks as if the required functionality is there.  It's just a matter of stringing everything together, taking the right acoustic measurements (I recommend measurements taken 1 m from the mouth of each loudspeaker in order to avoid non-minimum phase issues...which I found with Dirac, et al. taking measurements instead at the listening positions), you should get similar results.

 

9 hours ago, Jesal said:

FYI: I'm trying to see if I can improve on and replace my SH50. I already have BMS 4592NDs and 15" woofers. Still trying to source out the K402s if I can't, I'll have to DIY the horns.

 

In which country/region do you reside?  Klipsch apparently makes it difficult to acquire K-402s in other than North America, although it can be done.  Taxes and shipping fees usually become a factor for international sales.  Your plan for DIY horns of the Danley Synergy dual flare type is probably the most direct, cost effective path.  I recommend looking at the horn size and details of the Danley SH-96 size and shape, except you only need three drivers: the two 15" woofers on the off-axis ports of the horn, and the 2" compression driver on the throat port. 

 

Pictures of the reverse side of the SH-96 with its 11 drivers:

 

2619651027_f27f0151a7_b.jpg

 

and the view from the front:

 

PG_96.jpg

 

There is no need for the midrange drivers (6 of them are shown above), or the bass reflex ports on the side walls...rather only the two off-axis ports per 15" woofer (two woofers instead of four in the SH-96), with two through woofer ports of ~2" width and 5-6" long each--like that shown above.  That simplifies things dramatically.  The horizontal polars of that horn are shown at the bottom of the first post of his thread.

 

SH-96-Wire-Frame-ISO-View.jpg

 

The 11 drivers used in the SH-96 are due to the extreme SPL that the loudspeaker is designed to provide for fixed PA applications: ~133 dBSPL on-axis at 1 m, continuous.  The size of the horn is about equivalent to a K-402 or very slightly larger.

 

Chris

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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

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The Lynx Aurora 8 would certainly work, but also would definitely need a computer and software to set up the crossover slopes and delays/compensation. It's what I was going to do as well, although the MiniDSP or other more expensive options would be a LOT easier and probably get a good outcome more quickly and with less work.

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Hi Chris

I'm in Calgary Canada. I've contacted our local Klipsch dealer here and they're finding out if I can get the K402 or KPT-305 box. But I'm also open doing dual flares myself if the K402 route is too cost prohibitive. I will follow your footsteps and go with dual 15's and the BMS 4592.

Thanks a lot for your guidance, you'be been very helpful and it's much appreciated.
I will go with what I have on hand and see if I can make it work.

It's looking more like I'll be doing the SH96 style, as I have not heard from my local Klipsch dealer. 
I have a small room, 13'x15' feet that is open to the left (see attached)
Do you suggest going with 90degrees horizontal, considering it's a narrow room?

I can go 90 degrees if that is the best solution...

 

SH50.SKHornSub.jpg

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Posted (edited)
3 hours ago, Chris A said:

Here's the spreadsheet that I used in case you want to iterate the results for yourself:  Synergy Calc-100x70 straightnoflare 36x21 mouth.xlsx

Thanks for the spreadsheet. I can live with 26x40". That's not much bigger than what I have now. I will play around with it more.... Thank you Chris

Edited by Jesal

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25 minutes ago, Jesal said:

Do you suggest going with 90degrees horizontal, considering it's a narrow room?

Generally, yes.  However it's your room and you do have SH-50s there that you've lived with a while to make your own judgments.  I personally found the SH-50 to have too narrow a horizontal coverage as a center loudspeaker in my setup (15.5' width, 9' high, 40' length with Jubilees in each front corner about 10-12 feet away from the listening positions).   I could always point at the center loudspeaker in the setup when playing multichannel music and movies--because the apparent source width didn't integrate well with the corners.  (However, the Jubilees have no problem integrating in stereo mode across the width of the room.) I would err on the side of too wide a horizontal coverage rather than too narrow based on my center loudspeaker SH-50 trial.  With the K-402-MEH, this isn't an issue--I get a complete wall of sound with no sweet spot.

 

If I had two SH-50s, I could place them in my computer room (13.5' W x 12.5' L x 8' H) for a listen.  My computer room is a very difficult one to get anything that sounds good in it.  However, I basically never use any other room in the house for music than the main room (a den with fireplace). 

 

Chris

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1 hour ago, Jesal said:

I will go with what I have on hand and see if I can make it work... (see attached)

 

Your speaker system looks interesting. Maybe you just need to add an MEH center channel?

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53 minutes ago, Chris A said:

 I would err on the side of too wide a horizontal coverage rather than too narrow based on my center loudspeaker SH-50 trial.  With the K-402-MEH, this isn't an issue--I get a complete wall of sound with no sweet spot.

Will go with 90 degree horizontal. Hoping to start cutting wood when it warms up. Thanks Chris

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7 minutes ago, Khornukopia said:

 

Your speaker system looks interesting. Maybe you just need to add an MEH center channel?

Thanks, center channel is in the plan, just have to finalize the size/layout so it does not block the screen too much

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On 5/10/2020 at 11:44 PM, Chris A said:

Yes, it is, but progress has been suspended temporarily due to family health issues.  It will take a while before I'm able to return to MEH mold development.  It's been promising, but we are talking about a 25-35 pound (11.3--15.9 kg) horn in one part. It's a complicated mold.  After the horn itself, the box is a comparatively simple matter.

 

An alternative is to buy a pair of KPT-305s from Klipsch and modify them if you want them sooner (like I did for the K-402-MEH prototype).   I see Digitronic Italy apparently handles Klipsch Professional (cinema products) in the EU, which may still include the UK as I understand it.

 

Chris

Thanks, Chris. I will look into your suggestions a as a possible backup. 
 

Sorry to hear about the health issues in your family - all the best. 

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Posted (edited)

I would think with two K-402 MEH as L+R, with full wall to wall coverage, especially if you toe them in to cross a bit in front of the MLP, there’s no need for a Center channel (and thus also an acoustically transparent screen). 

Edited by NiToNi

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34 minutes ago, NiToNi said:

I would think with two K-402 MEH as L+R, with full wall to wall coverage, especially if you toe them in to cross a bit in front of the MLP, there’s no need for a Center channel (and thus also an acoustically transparent screen). 

In terms of soundstage they should perform just like Jubilees, which have that kind of soundstage performance...in spades.  Note that the center channel is for surround sound operation, mainly for handling soundtrack voices (and significantly increasing speech intelligibility) and locking in the center image even when listening off-center, as well as completing the whole front wall soundstage across the entire width of the room (side wall to side wall) where the K-402-MEH performs seamlessly in the middle between Jubilees. 

 

In fact, the K-402-MEH midbass response  is better since there are no polar lobing issues, i.e., the directivity of the loudspeaker is consistent from just below 200 Hz all the way through the top end.  This is actually better than Jubilee midbass/midrange performance, since there is only one horn mouth, not two, and no horn folds.

 

The bass performance of the K-402-MEH picks up ~12 dB of low frequency gain when in the room corner vs. in the center elevated against a wall, , i.e., very little EQ is needed to flatten its bass extension below 40 Hz, and deepens its bass extension even further.

 

Chris

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Posted (edited)

Audiolense is a state-of-the-art DSP FIR solution, you can’t do much better than that. Its only weakness is that it’s still not great at optimising multiple subs as a whole (it still does this by trying to flatten each individually). One workaround would be to use a miniDSP and optimise with MSO on top of using Audiolense (then with the multiple subs as “one” single sub in Audiolense). 
 

https://www.andyc.diy-audio-engineering.org/mso/html/

 

So Audiolense is a software that only generates FIR filters (crossovers, delays, EQ etc) based on acoustic measurements that you do directly in the program. You don’t need a powerful PC for this at all, an old laptop will do. To then actually use the filters, you need a so-called convolver. Audiolense now makes their own software convolver so you can set up a dedicated Windows 10 PC, preferably silent and reasonably powerful, with your Aurora 8 and it works exactly like a miniDSP but 100x better (ADC/DAC, noise, resolution etc) and fully automated (well, almost). 

 

Both JRiver and Roon have built-in convolvers so you can use the AL filters directly in these. If all your media is PC based, with no need to correct external sources, then this is EZ PC (no pun intended). Audiolense, a small PC and something like a miniDSP U-DAC8 would suffice to do an active 4-way. For higher-end, better DACs, more channels (HT) etc, there are better USB multi-channel DACs or external sound cards available from the likes of Emotiva, exaSound, RME, Mytek, Lynx etc. On the lower end, you can use the external sound card you’d need for measurements anyway (Audiolense, REW etc), eg a Focusrite Scarlett 2i4 for a pair of active 2-way speakers or even a 2i2 for EQ/room correction only (stereo). 
 

One caveat: Long high-resolution FIR filters (i.e. shitloads of taps) do introduce quite a lot of delay, making them unsuitable for live sound/tracking. This is also a problem for HT. It used to be that video processing (upscaling etc) was the CPU intensive part, hence the built-in possibility in processors to delay the sound to match the video, but for advanced DSP audio it’s now the other way around! Nonetheless, I’ve yet to see a video delayer, internal or external, available in the market although I’ve kept my eyes open for the last ten years or so... 
 

Audiolense may seem expensive but it’s the best solution available (together with Accourate) to tackle the weakest link in the audio chain - the room - and a superb toolbox/toy for DIYers who like to tinker with their stereos :)

Edited by NiToNi
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Thanks for the MSO link NiToNi, I might have to go that route later as I already maxxed out my 8 channels.

 

I agree, Audiolense is a keeper, I've had it for years and I could not part with it. Made my life simple or simpler.

 

As far as video delays, if you are using JRiver it's pretty easy. SHIFT + < OR > takes care of lip sync issues... https://wiki.jriver.com/index.php/Lip_Sync

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Wanting to try my hand at a synergy loudspeaker based upon Chris A's work with the K402.

 

Using his approximation of the k402 in HORNRESP one can see the double CRITES work very well.  The real trick is getting the CD driver part to sound good.

 

The K402s are $2500.00 per pair and this is the horn/CD driver/stand version.  The one with the box is no longer available I was told by the folks in Kentucky.

 

I have not seen any good photographs of the throat of the K402.  We all know that DANLEY SH series make no attempt to transition from the round entry to the square horn.

 

Of course, they are using those four inches drivers and the ports are so close to the CD entry that there would be no way to make a transition that would not spoil the ports.  One would think with the large format CD to 15 inches woofers does not require ports as close to the CD - we might be able to get away with it.

 

Can someone say, or show, what the throat looks like in the K402?  What little I can gather looks like there is a transition but it "happens" very quickly - almost immediately - maybe one half inch of smoothing between the entry and the transition to the walls.  I do realize there are no 90 degrees angles within the K402.  I would think something should be done to make those corners concave.  Should be simple to do with good ol' Bondo and some carefully cut pieces of wood.  I would recommend adding sand to the mixture. One would still have to be aware of the possibility of compromising the ports.  Not that I have any idea of how to do this.  Maybe having the ports more towards the centerline as Chris A has done with the K402.

 

And counsel would be appreciated.

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