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I've only recently started to read about this Synergy Horn. It looks likes a really smart solution. For me, I don't yet have enough knowledge to design one. If these things really can deliver clean uncoloured and dynamic sound then I'd consider it as a solution for my home hi-fi based on a tube amp. But is it realistic to consider DIY'ing a single horn that can reach from 20kHz down to 40Hz or 80Hz that I could bi-amp or tri-amp ??
Loud is not a requirement, I don't anticipate needing many drivers since this is home listening only.
Is there a DIY design out there for this frequency range ?
Loud is not a requirement, I don't anticipate needing many drivers since this is home listening only.
Is there a DIY design out there for this frequency range ?
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What attracts me to the Synergy horn is having only one horn, not having to make a mid-bass horn in addition to this (I'm looking at an all-horn solution). Plus, I can make single compression driver based Tractrix horn to cover few hundred Hz and up rather than the complexity of a synergy horn. So what would be attractive is one box, 2 or 3-way drivers which would get me something down to 80Hz where a sub could take over eventually but would be low enough for initial use without. I realize such a thing would be larger but I may be able to get 'permission' for that
How would you go about it ?
For home use I see no real gain in running a Synergy horn below the Shroeder frequency, and I'm getting a 2 way Synergy to get down to about 220 Hz, basically it's there. The driver so far are cheap.
Now make it a 3 way and you find that you get down to only about 200 Hz with horn loading, anything below that is the drivers now running as bandpass with gain from the horn lost. So now the drivers have to run as direct radiators and you need at least four woofers, if not 8. The cost suddenly hikes up for not much gain. I'd rather have a pair of good woofers.
A simple solution could be B&C 8PS21 - a nice bang for buck 8" that could probably work in a 2 way and get down low enough to cross to a sub. Port the rear chamber and as a direct radiator it will be a 6th order bandpass coupled to a horn.
Now make it a 3 way and you find that you get down to only about 200 Hz with horn loading, anything below that is the drivers now running as bandpass with gain from the horn lost. So now the drivers have to run as direct radiators and you need at least four woofers, if not 8. The cost suddenly hikes up for not much gain. I'd rather have a pair of good woofers.
A simple solution could be B&C 8PS21 - a nice bang for buck 8" that could probably work in a 2 way and get down low enough to cross to a sub. Port the rear chamber and as a direct radiator it will be a 6th order bandpass coupled to a horn.
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If I understand correctly, the Shroeder frequency is this the L.F. cut-off based essentially on the physical size of the horn. So for achieving lower frequencies than 200Hz (in my case 80Hz or lower) the requirement is that I make the horn larger - I'm prepared to do this. Is there any reason why I shouldn't (other than the obvious issue of size) ?
I guess what I'm saying is that I'm not looking to base my design directly off your project but rather to try and learn something from your knowledge and experience to understand a bit more about this unique Synergy horn approach.
I'm not (yet) concerned about the cost of the drivers - I'd only be concerned about the risk of buying an expensive driver and finding that it was the wrong choice and so the money was wasted. If an expensive driver (within reason) performs well, I'll get my value out of it. I know this might be different from your goals and I'm not trying to critique or change your approach, just trying to learn as all of this is rather new and difficult.
I'd prefer to cover 80Hz to 20Hz with a two-way and then below 80Hz with a separate box and 3rd channel.
Thanks.
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No, Schroeder freq is not a cutoff, it is a frequency below which the response becomes dominated by standing wave modes in a room (and so a waveguide doesn't make much sense since directivity won't be much of an advantage anymore). A horn could get you some better sensitivity, if that's your goal, but it going to have to be either in a corner and/or huge to really do much down at frequencies you might consider to be "bass".
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well 'huge' is all subjective.
http://www.diyaudio.com/forums/multi-way/132617-macondo-speakers-romy-cat.html#post1652331
These are Tractrix horns, single driver per horn. The largest one covers the upper base frequencies and goes low enough to cross-over to a sub. I have considered this option but the effort involved looks larger than the horn... one of those projects that you regret even starting
I thought a single horn, like the Synergy, looks like a much more practical option. But it's not a good option for me in this regard unless it goes low enough to cross over to a sub (and possible be useable even without a sub) or I still need another large box. I'm not necessarily afraid of making it fairly big like the one shown in the link. There will only be one - it's a mono project.
The constant directivity is a bonus, the more important benefit is that being a single horn it will be more practical to build it, install it and move it around compared to a multi-box option.
I'm still not sure what I'm missing here, before I discard the idea of a Synergy type horn I'd like to learn a bit more.
http://www.diyaudio.com/forums/multi-way/132617-macondo-speakers-romy-cat.html#post1652331
These are Tractrix horns, single driver per horn. The largest one covers the upper base frequencies and goes low enough to cross-over to a sub. I have considered this option but the effort involved looks larger than the horn... one of those projects that you regret even starting
I thought a single horn, like the Synergy, looks like a much more practical option. But it's not a good option for me in this regard unless it goes low enough to cross over to a sub (and possible be useable even without a sub) or I still need another large box. I'm not necessarily afraid of making it fairly big like the one shown in the link. There will only be one - it's a mono project.
The constant directivity is a bonus, the more important benefit is that being a single horn it will be more practical to build it, install it and move it around compared to a multi-box option.
I'm still not sure what I'm missing here, before I discard the idea of a Synergy type horn I'd like to learn a bit more.
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A lot of the midrange bandwidths discussed around synergy horns wouldn't seem to get the most out of a compression driver in a home situation. It's really no big deal to have a 1" CD cross below 1kHz. Especially with the narrower horns discussed here. I'd personally prefer to see good pattern control to well below 500Hz, preferring to go down to fschroeder and I'll gladly push the CD to make it all two-way.
The Synergy concept isn't conducive to a two way. Getting two octaves out of the mids is about the limit. Assuming a crossover of 1400hz or so, that means 350hz -1400hz. Each driver is basically a bandpass, and bandpass enclosures aren't known for wide bandwidth. If you want a Synergy to play low enough to mate with a sub, it will probably be a three way.
The VTC boxes are two-ways. I can't recall if they publish phase data, but I'm willing to bet it's not as smooth as the SH50. And the VTC boxes require DSP.
Have you tried any mids without a bandpass enclosure?......just wondering how pronounced any diffraction would actually be with a hole equal to the drivers actual radiating surface. With some depth offset, I see no need to expose the surround too. Just talkin out loud here.
A bandpass enclosure has a group delay centered right in the middle of it's passband
This group delay, a fraction of a millisecond, is enough to virtually move the midrange 'backwards'.
Without this delay, you would need DSP delay to line up the midrange with the tweeter.
An externally hosted image should be here but it was not working when we last tested it.
That's one of the reasons the Yorkville box has DSP
I wrote an article about this here: http://www.diyaudio.com/forums/multi-way/255303-understanding-synergy-horn-phase.html
Why would you not want to use the bandpass chamber on the mid? I've seen you mention it before, but I don't get it. It's really the crux of the design......
I guess because for home HiFI and not high output, the effects of power compression on the midwoofers in a bandpass seem like a paradox. While I certainly agree there's something special about a Fullrange point source, but is it enough to accept some of the inherent tradeoffs such as power compression and diffraction within the horn? Makes me reconsider 2" compression drivers crossed over much lower with a super tweeter.
I'm sure that Tom Danley and others have tried just about every configuration before settling for the current systems, but it's still fun to consider, discuss and try other options. For one, instead of cone mid drivers, what about midrange 1" compression drivers in plane wave tubes?
I can't imagine power compression being an issue for home use. Personally I wouldn't put the woofers on the horn and instead do a 2 way Synergy like Paul has here. I imagine having the mids in the horn with cone fully exposed would cause much of the diffraction you're concerned about....which is another benefit of the bandpass system on the Synergy with the small ports. The way JLH explains it when the mid ports are positioned correctly WRT the xo point, desired HF mid response, and the horn cross sectional area the compression driver won't put any pressure against the horn wall to create diffraction. I plan to do measurements when I get mine built with and without ports to test this.
I also think with an exposed mid and the different path lengths across the cone to the CD would cause issues. Plus, how would you mount them? For a 1khz xo with a 1" CD and 4" cone mids to get them close enough the throat of the horn would be nothing but mid cones! Unless you did a Paraline for the cd like Bateman showed.....
I get you on the new ideas, it can fun to speculate.
I also think with an exposed mid and the different path lengths across the cone to the CD would cause issues. Plus, how would you mount them? For a 1khz xo with a 1" CD and 4" cone mids to get them close enough the throat of the horn would be nothing but mid cones! Unless you did a Paraline for the cd like Bateman showed.....
I get you on the new ideas, it can fun to speculate.
Are we speaking from praactical measure or theory here?
Today i drew a 60x40 horn using a 1" celestion CD with four 2.5" Tympany cone mids whose position is as close to the CD throat as possible. If i draw parallel lines from the acoustic center of the CD and the mids taking into account the direct radiation from the cone's acoustic center, i'm less than 1 cm apart? That's far better than most off the shelf audiophile 2 ways with dome tweeters and 180mm woofers.
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