I think it would be great fun to build wooden horns like the Oris or the Azurahorn. I have a block diagram level understanding of how horns are designed and work. I am already aware of programs that aid in the design of horns. But seriously folks, I won't be able to do that in this lifetime. My specialty is making lots of sawdust.
I have been unable to find plans for horns that would increase the SPL's of a full range driver. I wish they were listed the way the cab choices are listed next to the drivers. I don't want to change what I love about these critters. I have found lots of horns for compression drivers. Is it possible to design a front horn for a full range driver that only increases SPL and does not introduce something unintended?
Whenever I state something like this in the FR forum, links to threads I could not find magically appear. I feel like a slacker for having asked, but then I really appreciate the leads. So, where do I find plans for Full Range Front Horns.
This speaker is going to be amplified by a 3w-5w 300B SET, which will be built for this speaker, and versa visa. I already have other combinations of amplifiers and full range speakers. I thought this combination would be interesting.
In consideration of the amplifier I thought of building La Scala clones for the Watt/SPL efficiency challenge and there are lots of spare Klipsch parts to be had out there. Making the cabs would be cake. My understanding of the choice to use a full range driver over a compression driver is that it is hard to get a compression driver with the range of a full ranger. I am fine crossing low with a FAST if I have to but with the intended music not including car crashes and punk rock it will likely not need it. Besides I already have a big silly system for car crashes and punk rock.
Thanking y'all in advance
I have been unable to find plans for horns that would increase the SPL's of a full range driver. I wish they were listed the way the cab choices are listed next to the drivers. I don't want to change what I love about these critters. I have found lots of horns for compression drivers. Is it possible to design a front horn for a full range driver that only increases SPL and does not introduce something unintended?
Whenever I state something like this in the FR forum, links to threads I could not find magically appear. I feel like a slacker for having asked, but then I really appreciate the leads. So, where do I find plans for Full Range Front Horns.
This speaker is going to be amplified by a 3w-5w 300B SET, which will be built for this speaker, and versa visa. I already have other combinations of amplifiers and full range speakers. I thought this combination would be interesting.
In consideration of the amplifier I thought of building La Scala clones for the Watt/SPL efficiency challenge and there are lots of spare Klipsch parts to be had out there. Making the cabs would be cake. My understanding of the choice to use a full range driver over a compression driver is that it is hard to get a compression driver with the range of a full ranger. I am fine crossing low with a FAST if I have to but with the intended music not including car crashes and punk rock it will likely not need it. Besides I already have a big silly system for car crashes and punk rock.
Thanking y'all in advance
A front horn can't be real full range. The biggest round horns of Oris or Azura get down to 200-160Hz only. It got to be a 2-way even the HT stuff is ruled out. (you don't want to listen to a piano which sounds like a toy). Or, can you accept a horn mouth of 1.5 m square?
In addition, the horns mentioned above load the driver to 2 kHz or so. Above that, the driver is on its own. For this, you'd need a driver with inherently rising response.
On the lower end, it'd be a hard choice. Few bass design besides horn can 'catch up with' the big horn above. For maintaining the coherence of huge dynamics and clean-cut rise and fall, eventually you'll build bass horn or huge dipole for 'completing' the system.
So you'll get a system which might do better car crash and punk rock than the other 'silly' system. Well, that's a good thing, too. Just not the way you think in advance.
If you are willing to give up full range front loaded, then there's a solution with compound horn - front & rear loaded. Typically front loaded down to 160-200Hz range, and rear loaded below that. Can be very good, too.
In addition, the horns mentioned above load the driver to 2 kHz or so. Above that, the driver is on its own. For this, you'd need a driver with inherently rising response.
On the lower end, it'd be a hard choice. Few bass design besides horn can 'catch up with' the big horn above. For maintaining the coherence of huge dynamics and clean-cut rise and fall, eventually you'll build bass horn or huge dipole for 'completing' the system.
So you'll get a system which might do better car crash and punk rock than the other 'silly' system. Well, that's a good thing, too. Just not the way you think in advance.
If you are willing to give up full range front loaded, then there's a solution with compound horn - front & rear loaded. Typically front loaded down to 160-200Hz range, and rear loaded below that. Can be very good, too.
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What you want is a WG to narrow up the driver's response below its upper mass corner [~2*Fs/Qts] to extend its response lower, but you can't go too low or the horn's acoustic mass will impact its mids, and especially its HF, too much.
Basically you're making an acoustic BSC to add an octave or two of 'LF' extension depending on the driver's specs, mids/HF frequency response.
Lowthers or similar is what you want specs/performance wise, so most drivers popular here will need a short, yet huge, WG, requiring digital delay to mate to a woofer system unless you don't mind them being located somewhat in front of the horns.
GM
Basically you're making an acoustic BSC to add an octave or two of 'LF' extension depending on the driver's specs, mids/HF frequency response.
Lowthers or similar is what you want specs/performance wise, so most drivers popular here will need a short, yet huge, WG, requiring digital delay to mate to a woofer system unless you don't mind them being located somewhat in front of the horns.
GM
A horn typcaaly has a band-width of 3-4 octaves, so the closest to a FR horn will be a FR in a back-loaded horn with a horn on the front as well.
Something like this:
Due to the small mouth lowest frequencies are likely by TL action and the highest direct radiation.
dave
Something like this:
An externally hosted image should be here but it was not working when we last tested it.
Due to the small mouth lowest frequencies are likely by TL action and the highest direct radiation.
dave
Thank you for your help. I am finding that you all are right. For some reason I can find a lot more on diyAudio using Google than the forum search engine. It looks like the compromise using a horn to increase SPL is a loss of extension into the lower registers, just as you point out. And yes, that is not what I was looking for in this amplifier/speaker project.
I need to move onto finding the most efficient full range speaker I can build. Space is not so much a problem and I have 20x30 feet of floor space but with the speaker placement needing to be out from the walls a bit because of book cases. I thought it would be fun to build a 300B SET and now I am trying to find the full range speaker that would best compliment it.
I need to move onto finding the most efficient full range speaker I can build. Space is not so much a problem and I have 20x30 feet of floor space but with the speaker placement needing to be out from the walls a bit because of book cases. I thought it would be fun to build a 300B SET and now I am trying to find the full range speaker that would best compliment it.
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Regardless of which tubes used, for tube amps in general and SET in particular, drivers should be chosen based on the Fs being the tuning, ergo this is as low as it will go and for max efficiency in a critically damped system [sysQ], the driver's Qts + amp output impedance should = 0.707.
Since BSC probably needs to be included in your app, then up to a 1.4 SysQ is required depending on the room, etc.. Historically, this is dialed in using variable damping factor [DF/bass boost] and/or a BLH.
From all this we see that with a high output impedance front end, one doesn't necessarily need a high efficiency driver to have a high efficiency system.
GM
Since BSC probably needs to be included in your app, then up to a 1.4 SysQ is required depending on the room, etc.. Historically, this is dialed in using variable damping factor [DF/bass boost] and/or a BLH.
From all this we see that with a high output impedance front end, one doesn't necessarily need a high efficiency driver to have a high efficiency system.
GM
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I built a tractrix based on the design spreadsheet provided by Volvotreter. More info with links to the design spreadsheet is here: http://volvotreter.de/downloads/Tractrix_v1.4b.zip
http://www.diyaudio.com/forums/full-range/261427-presenting-trynergy-full-range-tractrix-synergy.html
And here: http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html
With EQ'ing I am able to get the PRV 5MR450NDY to go from about 300Hz to 15kHz (about 5.5 octaves - and there were those who told me I was violating horn physics by getting more than 2 to 3 octaves but the data is there) - pretty close to full range for use with a supporting bass unit much like a FAST. The sensitivity is phenomenal - 109dB at 1m with 2.83v. Make sure you have earplugs when testing sweeps. Look at the distortion levels (0.088%) at a reasonably loud listening level of 92dB. It sounds very clean.
Member Kees52 has been following along on my journey and is working on his bendy MDF build of a smaller tractrix here: http://www.diyaudio.com/forums/full-range/261427-presenting-trynergy-full-range-tractrix-synergy-49.html#post4241323
http://www.diyaudio.com/forums/full-range/261427-presenting-trynergy-full-range-tractrix-synergy.html
And here: http://www.diyaudio.com/forums/full-range/259293-prv-5mr450-ndy-fast-applications.html
With EQ'ing I am able to get the PRV 5MR450NDY to go from about 300Hz to 15kHz (about 5.5 octaves - and there were those who told me I was violating horn physics by getting more than 2 to 3 octaves but the data is there) - pretty close to full range for use with a supporting bass unit much like a FAST. The sensitivity is phenomenal - 109dB at 1m with 2.83v. Make sure you have earplugs when testing sweeps. Look at the distortion levels (0.088%) at a reasonably loud listening level of 92dB. It sounds very clean.
Member Kees52 has been following along on my journey and is working on his bendy MDF build of a smaller tractrix here: http://www.diyaudio.com/forums/full-range/261427-presenting-trynergy-full-range-tractrix-synergy-49.html#post4241323
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Front horns and full ranges can be great fun, but as has been pointed out, you are stuck with a 'FAST' type two way, and the choice bass driver will make a big difference.
My favorite so far has been a relatively shallow 'waveguide' like GM described. Something sized to support around 250hz is about optimum. If you make it much larger, the beaming will drive you nuts. A WG not technically a horn, but there's enough directivity gain to lift the lower end of the range significantly. I've done a few of these, but the longest lived was a 6" fostex combined with a large pro driver in a corner loaded reflex box.
If a two-way is too much complication, and you want to build a true one way, the options are extensive if not endless. Efficient and good bass usually means going to a larger full range like an 8" but most of these are either not quite full range, or very expensive. Deciding on a driver size is not a bad place to start.
Just to throw out a couple random ideas: Seas FA22 in a Metronome, Fostex FE166 or L Cao in a Karlsonator 6, Alpair 12p in a big BLH.
My favorite so far has been a relatively shallow 'waveguide' like GM described. Something sized to support around 250hz is about optimum. If you make it much larger, the beaming will drive you nuts. A WG not technically a horn, but there's enough directivity gain to lift the lower end of the range significantly. I've done a few of these, but the longest lived was a 6" fostex combined with a large pro driver in a corner loaded reflex box.
If a two-way is too much complication, and you want to build a true one way, the options are extensive if not endless. Efficient and good bass usually means going to a larger full range like an 8" but most of these are either not quite full range, or very expensive. Deciding on a driver size is not a bad place to start.
Just to throw out a couple random ideas: Seas FA22 in a Metronome, Fostex FE166 or L Cao in a Karlsonator 6, Alpair 12p in a big BLH.
Re the Tractrix: You're not horn loading to anywhere near 15 kHz with a throat that equates to a ~3.137" diameter and barely to the driver's mass corner judging by it and the polars, so Motor Nature's 'chastity' is still intact 😉.......... To horn load a driver to 'x' frequency requires that the throat be a bit < its diameter.
GM
GM
Had I put a constriction in the throat so that it is less than Sd, there would be a bandpass effect proportional to Sd/Vol-front-chamber, and for sure, the horn would *not* reach 15kHz. As it is, the HF's are making it through and with pretty good sensitivity - consistent with the Akabak model.
Funny in Akabak a horn is made up of waveguide elements with prescribed throat, mouth, length, type of expansion (conical, exponential, catenary, etc). I think I modeled the tractrix using 15 consecutive waveguides to get the detailed resolution on the dimensional changes. The final segment can be a waveguide or "horn". The latter having the radiator calculated as a 3d object with numerous elements with spherical wavefronts of prescribed horn mouth curvature size.
True, and a phase plug would be needed to get the HF out at a reasonable efficiency over some arc to get to 15 kHz, but the bottom line is that above the throat's BW it's just a typical 'rising on axis' WG that at best is only going to have as much output on axis as a direct radiator.
We call them horns due to their shape and list their horn + driver usable BW, but they aren't horn loaded over their entire BW as you implied.
GM
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