A large synergy horn

[Droogne]

Full build thread will follow, for now just some pics and modelling. 

Idea is a big ass 2-way synergy horn, using the new horn designed by Omholt and Don Keele, measuring a whopping 108 x 75 x 38cm. Compression driver is not been chosen yet, but the horn is a 1,4" throat. I will probably start with a JBL 2447 and upgrade from there. 

 

Modelling is done in hornresp, based with these specs (and a 262L backchamber voume):

Driver modelled is the one I have, the Eminence Kappa 15C. I only modelled a single driver, but I will be using 2 so you can add 6dB (due to coupling). I used full RMS power for the modelling as I use active crossovers. Crossover will be at 500hz, but for simplicity I put the off axis port at 536hz (1/4fth WL = 16CM aka L12 con), which is where the horn goes from conical to exponential.

µhalf-space

eight-space/corner

When this driver would be mounted in a sealed configuration:

To match most 2-way large compression drivers (which can hit 135dB at RMS) I was hoping to achieve this (or even +6-9dB) with the woofer section (100-500hz) and subwoofers (30-100hz). I can go up to 4x 18" woofers if need be. You can see there is almost no hornloading below 100+hz, so trying to push for lower extension is not what I'm gonna do. For Sub 100hz I will one day be building Othorns or other large horn subwoofers (recommendations welcome!) as I can bring the mouth center of large hornsubwoofers close enough to the synergy as to make it a point-source (1/4th WL of 100hz is 85cm).

Design

Still working out a lot of kinks, primarly the woofer mounting pads and structural stiffness of the horn, but I will be copying the follow design (without the LF ports and midbass woofers though): 
 

[Ricci]

I will be following this. I want to try my hand at a synergy one of these days but just havent gotten around to it. 

[dgage]

I really liked Brandon’s SH50s but wish the high-end was more detailed and didn’t drop off before 20,000Hz. The staging was incredible but it was just missing the detail and extension of other speakers I’ve heard.  It’s a shame Danley haven’t put out a dedicated HT version as I’d think it would be a very good seller.  But I understand as a business they may not want to go that direction or have too many other focuses.  Too bad for us.

[lilmike]

I'll be following along.

I really, really want some Synergy horns, I was experimenting with some a while back, but lots of other things got in the way of ever finishing them. I was fortunate enough to be able to check out Bill Waslo's current setups recently,. that definitely rekindled the desire to have my own. 

As usual, I have plenty of ideas, lots of parts, and nowhere near enough time to turn any of it into reality.

[Rivilee]

Interesting. I'm not finding that horn anywhere. Closest I've found is the K402 with 2 15" drivers in a synergy setup. https://community.klipsch.com/index.php?/topic/161404-a-k-402-based-full-range-multiple-entry-horn/

https://www.stereo.net.au/forums/topic/232459-klipsch-k402-replica-build/

[Droogne]

3 hours ago, Rivilee said:

Interesting. I'm not finding that horn anywhere. Closest I've found is the K402 with 2 15" drivers in a synergy setup. https://community.klipsch.com/index.php?/topic/161404-a-k-402-based-full-range-multiple-entry-horn/

https://www.stereo.net.au/forums/topic/232459-klipsch-k402-replica-build/

I literally have the first pair ever build. Omholt and Don Keele were inspired by the K402, but wanted some improvements, which they (say they) hit. Ibought the first ever prototype they build. You will not be able to buy the horn seperately. You can see I'm extremely lucky! I dont have any definitive measurements yet, as Omholt didnt have the correct settings to do those yet, but the in-room comparison with the K402 is remarkable! Way better in some aspects.

 

[Droogne]

On 6/18/2019 at 2:50 PM, dgage said:

I really liked Brandon’s SH50s but wish the high-end was more detailed and didn’t drop off before 20,000Hz. The staging was incredible but it was just missing the detail and extension of other speakers I’ve heard.  It’s a shame Danley haven’t put out a dedicated HT version as I’d think it would be a very good seller.  But I understand as a business they may not want to go that direction or have too many other focuses.  Too bad for us.

I'll probably end up with a Radian 951Be, TAD4002z or BMS4594 to ensure high quality high end. I'm also gonna shift the crossover to 650 -3dB/700hz -0dB to make sure I dont push the drivers to much when going for high SPL. In the synergy horn concept, there is not as big an advantage to use a lower 500hz instead of the higher 700hz crossover. Most woofers will also be able to get up too 700hz so no problem there. Low output extension is not possible in the synergy, except if you accept the fact that there is no hornloading down 120hz or something in half space. There is a huge difference when corner loaded though. In any case, trying to push the extension lower is not worth it I think as you can keep the point-source by just adding a subwoofer close enough. In my case I'm gonna use an othorn (or maybe something smaller, but with similar low end extension if possible) to make a 20-20000hz -3dB point source. 

Business model aside, a home-theatre Danley Sound version would be awesome! A carefully designed 2-way for LCR and smaller voice-matched versions for surrounds.

 

 

[Droogne]

Biggest working points right now are:

1. Making sure I can mount the woofer pad to the horn, without creating an incredibly deep port (the pad is already 3/4th inch, and I have a 1" gap between the mounting pad and the horn, due to the curve of the horn). I will be using Epoxy to fill the space between the pad and the horn. To keep the ports as shallow as possible I will be rounding them down to 1 inch away from the port itself. This will make it act less like a 1,75" deep port, and keep the chamber between the woofer and the port as small as possible. 

2. Make sure all the internal bracing that is fixed to the horn can be decoupled from the surrounding box, so I can still take out the horn (with its attached woofer mounting pads and bracing) later to change out woofers etc. This will mean not gluing, but rather screwing the bracing to the box. 

 

 

 

 

[Ricci]

17 hours ago, Droogne said:

I'll probably end up with a Radian 951Be, TAD4002z or BMS4594 to ensure high quality high end. I'm also gonna shift the crossover to 650 -3dB/700hz -0dB to make sure I dont push the drivers to much when going for high SPL. In the synergy horn concept, there is not as big an advantage to use a lower 500hz instead of the higher 700hz crossover. Most woofers will also be able to get up too 700hz so no problem there. Low output extension is not possible in the synergy, except if you accept the fact that there is no hornloading down 120hz or something in half space. There is a huge difference when corner loaded though. In any case, trying to push the extension lower is not worth it I think as you can keep the point-source by just adding a subwoofer close enough. In my case I'm gonna use an othorn (or maybe something smaller, but with similar low end extension if possible) to make a 20-20000hz -3dB point source. 

Business model aside, a home-theatre Danley Sound version would be awesome! A carefully designed 2-way for LCR and smaller voice-matched versions for surrounds.

 

 

There is also the new B&C coax to consider. DCX464-12

The Skram is 4" less deep than the Othorn  and a bit lighter, but with comparative performance and more flexibility due to variable port tuning. Might be a consideration. 

 

[Droogne]

20 hours ago, Ricci said:

There is also the new B&C coax to consider. DCX464-12

The Skram is 4" less deep than the Othorn  and a bit lighter, but with comparative performance and more flexibility due to variable port tuning. Might be a consideration. 

 

SKram looks awesome! Dont see any ouput measurents yet. Havent had time to go through all the pages, but dont see the Skram listed in the systems list. Looks like a better solution! Definetly with those new driver choises! Awesome!

[Droogne]

The DCX464 also looks like a contender, definitely in the SPL field. I dont know anything about its quality yet though, which will be a major deciding factor.

[Ricci]

On ‎6‎/‎22‎/‎2019 at 7:44 AM, Droogne said:

SKram looks awesome! Dont see any ouput measurents yet. Havent had time to go through all the pages, but dont see the Skram listed in the systems list. Looks like a better solution! Definetly with those new driver choises! Awesome!

I don't have cabs yet so testing is a ways off. However I'm confident in how it will perform based on previous experience.

I'm also confident the B&C DCX464 is going to be a heckuva product. They clearly spent a long time developing it and I'm sure the had the BMS units in their sights while doing so. Competition is great.

[SME]

What is/are the intended application(s)?  Home vs. PA; indoor vs. outdoor; 4 pi vs. 2 pi vs 1 pi vs 1/2 pi?

I think a XO at 700 Hz may be too high because of the rapid roll-off of the woofers, which will tend to make phase shift very fast.  It may be do-able if the DSP capability is very strong, but even then it may be tricky.  Alternatively, use smaller drivers and give up some bass extension which isn't really horn loaded anyway.  If you really want subs that can keep up in a PA scenario, you'll want at least a Skhorn for each I think.  The Skhorn can likely cross higher than the Skram can too.

Of course much of this thinking depends on application.  Are you really going to hit 135 dB RMS @ 1 meter at home?

[Droogne]

On 6/24/2019 at 10:49 PM, SME said:

What is/are the intended application(s)?  Home vs. PA; indoor vs. outdoor; 4 pi vs. 2 pi vs 1 pi vs 1/2 pi?

This is the "interesting" exercise here. I want to build the (almost) highest audio quality speaker I can, but where possible I also want to increase it's SPL. Using coaxial driver's comes to mind. Using more LF drivers than necessary for home use comes to mind too. 

As I will be playing at consideringly lower volumes at home Ill be able to get away with a lot more EQ, and the enormous output capabilties of all the coupled LF driver's will give me a lot of space to extend the frequency down lower. That's why I'll be modelling for a PA setup in halfspace (2 pi), with a 100hz +-0dB. I trust if I get that right, I can extend the response some lower with corner/wall loading and PEQs.

I think a XO at 700 Hz may be too high because of the rapid roll-off of the woofers, which will tend to make phase shift very fast. 

I modelled the woofers, and as long is I pick the correct woofers I can easily get a 700hz -3dB. This is ofcourse also why I picked a 100hz lower xover point. Makes it easier to find a woofer that can reach the 700hz. 

What do you mean by the phase shifts? :d

It may be do-able if the DSP capability is very strong, but even then it may be tricky.  Alternatively, use smaller drivers and give up some bass extension which isn't really horn loaded anyway.  If you really want subs that can keep up in a PA scenario, you'll want at least a Skhorn for each I think.  The Skhorn can likely cross higher than the Skram can too.

Of course much of this thinking depends on application.  Are you really going to hit 135 dB RMS @ 1 meter at home?

 

 

[Droogne]

I might try out other woofers than the Em Kappas. Any suggestions? 100-700hz -3db. T/S parameter 'guideline' also welcome.

[Droogne]

@Ricci@SME 

 

Hey  after a lot of modelling, and discussing on DIYaudio I came to the conclussion that I can both use 12" woofers instead of 15  (or 18") woofers AND that it will be the best option if I want to reach the best quality. Due to cancellation because of relative distance between the center of the cone surface and the port into/through the horn, using a 15" woofer with a 650hz crossover would be a bad idea. 12" and 650hz is fine. 650hz is also way better for the CD, so thats why I'm going that route.

Using 12" woofers means its harder to get high SPL and a low crossover to the subs, so thats why I will be going for a 120hz -6db (although it will end up being 100hz -6dB) as that point will allow me to use less woofers to reach the same point. I'm probably gonna use something like the Beyma 12 p80fe, which will get me an extremely high 100hz and up level. 

This gets me to 100hz and lower.. I dont really want to rely on subs only, as they are spaced to far from the synergies.. Or shouldnt I worry about this? I mean, having mains that go down to a usefull 40hz looks really beneficial to me, so rolling off at 100hz might dissapoint. I was thinking about using some simple vented 15" cabs (2 for each synergy) for 40-100hz, but would love to hear your thoughts on this. The Skram looks awesome, but wont get me the 130db 100hz RMS I want. Or will it? In any case, I dont need those cabs to go down as low, 40-50hz is fine. I'll add subs for anything below that. Maybe some suggestions for some good horn loaded 40-100hz cabs? Something like the LaScala but for little bit lower (lascala loses down 100hz already)

Or how do you see the sub vs main placement? Would I be able to locate the subs and recognize the sub 100hz sound coming from the subs instead of the mains  themself? Because if I cant I wont bother with making new subs, and just use the synergies in home with a 100hz crossover, and give everything below 100hz to my Sundown Audio sealed subwoofer pair. 

 

 

 

 

[SME]

It's funny, but you posted this about the same time I was exploring horn-loaded "mid-bass" designs with good HF extension as well, and was frustrated to see that OB mounting of a 15" dropped like a rock just a bit too soon for a good XO to the CD+horn combo I was looking at.

I'm glad you figured this out and moved to 12".  And then you probably encountered the fact that 12" pro woofers seem to be either very sensitive with roll-off in the 100s Hz or they are "subwoofers" which are not very good for a mid-bass horn.  There seems to be no middle ground.  Perhaps that's why I don't see many mid-bass horn designs that cover above ~300 Hz?

Anyway, to your question about subs.  I wouldn't worry at all about a 100 Hz crossover.  Bass localization is a weird thing that, IMO depends on a lot more than crossover choice.  If your sub makes a lot of noise or distortion in the HFs, it will cause localization.  If your sub has problematic HF resonances in the cabinet and/or vent system (e.g. organ pipe resonance) , lower XO may help but that won't fix distortion harmonics exciting these resonances.  Another thing is that listeners can perceive extreme pressure differences between ears, and if one is sitting "in a bass null" where pressure vs. location changes very rapidly, the bass can seem directional, making it sound like it may be coming from one sub or another.  This may be accentuated if there is a resonance there also.  And finally, the sound quality of the tops is important.  If the tops are clean, especially in the same frequency range as unwanted harmonics from the subs, you'll be less likely to hear the subs because you'll be paying attention to the music from the speakers.  :)

Assuming this is all in a smaller room, I think XO frequency may be even less critical.  In such a room, you're hearing the sound in a  "well mixed" state.  Localization information may not be useful for those frequencies.  I wouldn't be surprised if a well-optimized small room system could get away with bass management (i.e. using multiple in-room sources) for frequencies as high as 250 Hz.

Now I have to ask again, do you really need 130 dB SPL @ 100 Hz for home listening, with just one of the two channels?  At the seats or at 1 or 2 meter?  That's real loud ya know!  If you want that kind of SPL capability *and* want to enjoy some bass extension, you're gonna need some crazy subs.  You might damage something with that kind of setup.  That said, I think a Skram could probably do it depending on the distance, driver and amp choice, etc.  But will it have enough at lower frequencies?  Hmm, maybe you should build a pair of Skhorn instead.  I wouldn't bother with anything less than one of these if you are serious about that 130 dB SPL @ 100 Hz spec.

[chrapladm]

Skram or IPAL Othorns would work I believe. Not sure why the need for 130db at 100hz either. My future project (SH) was going to be using the Skram's because of the versatility of them being able to be used for HT. Not saying the Skhorn cant but the pair of Skrams will work great under a SH, I feel at least for music or HT.

[Droogne]

On 7/12/2019 at 10:26 AM, SME said:

It's funny, but you posted this about the same time I was exploring horn-loaded "mid-bass" designs with good HF extension as well, and was frustrated to see that OB mounting of a 15" dropped like a rock just a bit too soon for a good XO to the CD+horn combo I was looking at.

I'm glad you figured this out and moved to 12".  And then you probably encountered the fact that 12" pro woofers seem to be either very sensitive with roll-off in the 100s Hz or they are "subwoofers" which are not very good for a mid-bass horn.  There seems to be no middle ground.  Perhaps that's why I don't see many mid-bass horn designs that cover above ~300 Hz?

 

On 7/12/2019 at 10:26 AM, SME said:

Anyway, to your question about subs.  I wouldn't worry at all about a 100 Hz crossover.  Bass localization is a weird thing that, IMO depends on a lot more than crossover choice.  If your sub makes a lot of noise or distortion in the HFs, it will cause localization.  If your sub has problematic HF resonances in the cabinet and/or vent system (e.g. organ pipe resonance) , lower XO may help but that won't fix distortion harmonics exciting these resonances.  Another thing is that listeners can perceive extreme pressure differences between ears, and if one is sitting "in a bass null" where pressure vs. location changes very rapidly, the bass can seem directional, making it sound like it may be coming from one sub or another.  This may be accentuated if there is a resonance there also.  And finally, the sound quality of the tops is important.  If the tops are clean, especially in the same frequency range as unwanted harmonics from the subs, you'll be less likely to hear the subs because you'll be paying attention to the music from the speakers.  :)

Thanks, makes a lot of sense ;) In any case, best way might be to try it out! Best way might be to just try it out with the speaker I have right now.. Also, highest level I modelled was 120db @100hz (xmax limited with 3dB leftover to allow peak). In home highest level I ever listen to is 115-120dB, but only in very short amounts of time. Regular 'high' levels are at least 10db lower. I have the option to buy 2x 12P80Fe second hand for a very good price, so I'll use those to start with. One in each synergy. I'll make the ports for the 4 other woofers, and close them off from the inside. I'll add the woofers when I feel the need too (I only need those ridiculously high SPL levels in certain situations, which isnt any time soon). The Beyma 12MC700Nd is still for sale (the 12P80Fe is not, sadly enough) but it models almost the same so I think I can combine (especially if I just correct the 1dB difference by using a different amp, that way I dont need any extra DSP channel). If I model these woofers to allow a 80hz -6db crossover I can only reach 113dB, so I can use both of them when using limiters to make sure I dont exagerate and go for the higher levels.

12P80Fe:

12MC700Nd:

 

On 7/12/2019 at 10:26 AM, SME said:

Assuming this is all in a smaller room, I think XO frequency may be even less critical.  In such a room, you're hearing the sound in a  "well mixed" state.  Localization information may not be useful for those frequencies.  I wouldn't be surprised if a well-optimized small room system could get away with bass management (i.e. using multiple in-room sources) for frequencies as high as 250 Hz.

Now I have to ask again, do you really need 130 dB SPL @ 100 Hz for home listening, with just one of the two channels?  At the seats or at 1 or 2 meter?  That's real loud ya know!  If you want that kind of SPL capability *and* want to enjoy some bass extension, you're gonna need some crazy subs.  You might damage something with that kind of setup.  That said, I think a Skram could probably do it depending on the distance, driver and amp choice, etc.  But will it have enough at lower frequencies?  Hmm, maybe you should build a pair of Skhorn instead.  I wouldn't bother with anything less than one of these if you are serious about that 130 dB SPL @ 100 Hz spec.

110-115dB at seat level is the absolute highest (including subs, which were running 6-10db hotter than the mains) I can take, and most of the time at least 5-10dB lower at 'high levels'. So no, I absolutely dont need this kind of levels. The fact is that is I do want more reserve AND I want to use them for the festival/live projects we regulary do with our youth movement. In that case I do want as much SPL as possible. 

So the focus is keeping to all the principles for absolute max quality, and within those limits go for the highest SPL. 

[Droogne]

Ended up buying the Beyma 12P80Fe. Very heavy and solid driver! I'm gonna start with 2.  

[Droogne]

On 7/12/2019 at 11:58 AM, chrapladm said:

Skram or IPAL Othorns would work I believe. Not sure why the need for 130db at 100hz either. My future project (SH) was going to be using the Skram's because of the versatility of them being able to be used for HT. Not saying the Skhorn cant but the pair of Skrams will work great under a SH, I feel at least for music or HT.

 

On 7/12/2019 at 10:26 AM, SME said:

It's funny, but you posted this about the same time I was exploring horn-loaded "mid-bass" designs with good HF extension as well, and was frustrated to see that OB mounting of a 15" dropped like a rock just a bit too soon for a good XO to the CD+horn combo I was looking at.

I'm glad you figured this out and moved to 12".  And then you probably encountered the fact that 12" pro woofers seem to be either very sensitive with roll-off in the 100s Hz or they are "subwoofers" which are not very good for a mid-bass horn.  There seems to be no middle ground.  Perhaps that's why I don't see many mid-bass horn designs that cover above ~300 Hz?

Anyway, to your question about subs.  I wouldn't worry at all about a 100 Hz crossover.  Bass localization is a weird thing that, IMO depends on a lot more than crossover choice.  If your sub makes a lot of noise or distortion in the HFs, it will cause localization.  If your sub has problematic HF resonances in the cabinet and/or vent system (e.g. organ pipe resonance) , lower XO may help but that won't fix distortion harmonics exciting these resonances.  Another thing is that listeners can perceive extreme pressure differences between ears, and if one is sitting "in a bass null" where pressure vs. location changes very rapidly, the bass can seem directional, making it sound like it may be coming from one sub or another.  This may be accentuated if there is a resonance there also.  And finally, the sound quality of the tops is important.  If the tops are clean, especially in the same frequency range as unwanted harmonics from the subs, you'll be less likely to hear the subs because you'll be paying attention to the music from the speakers. 

Assuming this is all in a smaller room, I think XO frequency may be even less critical.  In such a room, you're hearing the sound in a  "well mixed" state.  Localization information may not be useful for those frequencies.  I wouldn't be surprised if a well-optimized small room system could get away with bass management (i.e. using multiple in-room sources) for frequencies as high as 250 Hz.

Now I have to ask again, do you really need 130 dB SPL @ 100 Hz for home listening, with just one of the two channels?  At the seats or at 1 or 2 meter?  That's real loud ya know!  If you want that kind of SPL capability *and* want to enjoy some bass extension, you're gonna need some crazy subs.  You might damage something with that kind of setup.  That said, I think a Skram could probably do it depending on the distance, driver and amp choice, etc.  But will it have enough at lower frequencies?  Hmm, maybe you should build a pair of Skhorn instead.  I wouldn't bother with anything less than one of these if you are serious about that 130 dB SPL @ 100 Hz spec.

 

On 7/12/2019 at 11:58 AM, chrapladm said:

Skram or IPAL Othorns would work I believe. Not sure why the need for 130db at 100hz either. My future project (SH) was going to be using the Skram's because of the versatility of them being able to be used for HT. Not saying the Skhorn cant but the pair of Skrams will work great under a SH, I feel at least for music or HT.

I have decided that there are 2 options, considering my latest driver choice which will give me a 150hz -2db. (NOTE: skip to end conclusion for a more coherent text. I got caried away when typing, but I do like my thoughts included in this post).

1. for maximum SPL: use a 120 or 150hz highpass on the synergy, and place it on top of a kickbin (80-150hz) OR sub that can reach this high (Skram for example). This would end up at 2pi, 123dB at 150hz for 1 woofers, so ~135dB using 4 woofers. 

• being able to seperate tops (synergy + kickbin) from the subs will be a big advantage IMO, which allow for better subplacement. 
• seperating subs from the synergies, without using a kickbin would not be ideal with a 120-150hz crossover
• QUESTION ( @Ricci) : how many Skrams would I need. Considering 2 Skrams are 1 Skhorn and hits 146dB (125hz, continuous, 2 meter RMS, 2 pairs of vents open)? So 152dB at 1 meter? And around -6dB for 1 Skram so back at 146dB. Than 1 Skram already looks like overkill as it would have an +11dB advantage on the synergy.
• See dB continious, 2m for the Skhorn below. This would mean a single Skram would match the 150hz crossover down to at a little bit higher than 35hz,.. awesome!? Using he 1 pair of vents open option would still yield a powerfull enough respons up to 125hz and has a more powerfull 20hz SPL, but would be matching at 50hz intead of at 31,5hz (all vents open) For music this doesnt look like a good tradeoff. 
•  
•                                                  10hz        12,5hz       20hz          25hz          31,5hz      40hz         50hz           63hz         80hz          100hz       125hz

• all vents open                                             103.8        125.6         135           139.1        139.2         140.4       144.2         145.4         146.2    1 pair of vents open                 99.7 116.6 119.8  122.7 127.5 134.4 137.2 139.5 143.5 144.6                                              Othorn                                        94.3 106.1 122     128.3 132.2 131.5 133.3 133.9 135.8 136

 

2. for in home use I the synergy would play (1pi) 120dB 80hz before hitting Xmax. Definetely no kickbin needed as with 4x woofers Id still hit 132dB for each synergy.  Having Skrams with 1 pair of vents open, Id hit ~140dB 80hz and ~117dB 20hz  (which are 2 pi measured values.. so 1pi  146dB 80hz and 123dB 20hz). Only a match down to ~40hz, but mathching isnt as important in home, as I will definetely not reach those SPL levels, so I would probably still be more than fine with 2 skrams blasting 123dB 20hz in the living room (especially considering I might be able to corner load them AND use them in pairs which will add another 3dB). 

 

=> this makes it obvious for me that matching the 80-150hz range is not gonna be the hardest part. Matching down to 40hz (which is an acceptable highpass for live music) seems to work fine, but then I wouldnt have any ramp up for the lower end (which I would like to be +~3dB between 40 and 120-150hz). Going even lower than 40hz will start being more problematic as the Skhorn/Skram drasticaly loses SPL. So yes the Skram/Skhorn might be a good match for 40-150hz, but it's overkill for 80-150hz. A dedicated kickbin for 80-150hz range (smaller cabinet, lower weight, lower costs etc) and then using an Othorn for a stronger respons down to 25-40hz might be a better plan. At 25hz this would be 128db (1 meter instead of 2 as listed above) so ~2dB more than a Skram all vents open, and at 40hz there would be 0dB difference. So in the sub 80hz range it looks like the Skram would outperform the Othorn for regular music/PA use, but would be outperformed by an Othorn+kickbin down to 25hz (and it would allow for seperating of synergy+kickbinfrom the subs for better subwooferplacement, subwoofercoupling, mounting on stages,..)

 

==> CONCLUSION:

Skram is the easy option because it would allow for less bins necessary (as in: no kickbins) and stronger performance in the most common music range (40-...hz range), but sadly this is only true when comparing them in similar setups. Stacking all subs together, instead of splitting them inhalf into two equal stack gives them an extra 3dB, but this is only possible when using kickbins. When using kickbins, the big advantage of the Skram dissapears. When using the Skrams and synergies instead of Skram and Synergies+Kickbin I lose the 3dB advantage of stacking all subs together instead of splitting them in half. The Othorn is a stronger 25-80hz sub than the Skram is, the Skram on the otherhand is a stronger 40-80hz sub. I prefer a good 25-80hz range so my prefered setup would be Othorn and Synergy+Kickbin.  

I could already achieve a +2dB at 25hz (143dB) vs a pair of Synergies at 150hz (141dB) with only 4 Othorns. For Skrams (not coupled all together, but rather split into 2 equal stacks) to achieve this +2dB at 25hz I would need 2x4 of them. 

 

NOTE: I only used simple dB adding for calculations. The larger hornmouth that is created by coupling is not take into consideration.

NOTE: all values uses, unless otherwise specified are at 1 meter RMS

 

 

[Droogne]

Picking a good kickbin is the next dilemma. I only need a -6db between 80-150hz, so.. 60-200hz -3dB. 2 kickbins coupled together for each synergy? 2 dB in this range vs 150hz crossover 

=> kickbin that can do 80hz 123-129dB (not exceeding Xmax!) 

[SME]

I think most would probably want to cross the Skram a fair bit lower than the vent resonance at 150 Hz, like maybe 120 Hz or even less.

[Droogne]

16 hours ago, SME said:

I think most would probably want to cross the Skram a fair bit lower than the vent resonance at 150 Hz, like maybe 120 Hz or even less.

Good point. An extra reason to consider the Othorn. Skram only wins in my eyes, if it could work as a bin for 150hz too.

 

For now I didn't realy consider the build complexity, costs, Amp requirements and size. So this will be the next step. Skram does look smaller and less complex. Gonna hear how much my carpenter would charge for each, and look at driver costs. 

[chrapladm]

Anymore progress?