David, thanks for the clarification! After reading a bit more (should have done that in the first place) it makes sense why you have done it that way. I read elsewhere that as the frequency rises the increasing directivity generally balances the sound power roll off (which is around 6dB/octave for a rigid piston in an ideal scenario). So without having to figure out the directivity and sound pressure levels, assuming the infinite baffle FR is acceptable, we could just simulate the driver in an infinite baffle to obtain a "baseline" sound power level plot and compare any other results to that to see if the HF response is affected.
I've been slowly going through the 2-3 inch drivers under $30 available on Parts Express and there are at least 10 really good candidates for horn loading above 200-300Hz.
frangus, have you tried any other drivers in the horns yet? The HiVi A2S seems to be less suited to horn loading than a lot of these other 2-3 inch drivers, so it would be interesting to hear what you think of some other drivers.
I've been slowly going through the 2-3 inch drivers under $30 available on Parts Express and there are at least 10 really good candidates for horn loading above 200-300Hz.
frangus, have you tried any other drivers in the horns yet? The HiVi A2S seems to be less suited to horn loading than a lot of these other 2-3 inch drivers, so it would be interesting to hear what you think of some other drivers.
My experiments with ~the same (slightly enlarged) horn:
Really dodgy-looking 2" drivers from home theatre satellites worked surprisingly well.
Of the larger drivers, only the P.Audio SN4-60F was reasonably smooth. Motor strength seems only to change efficiency (not extension), as shown by:
http://www.diyaudio.com/forums/full...-horns-low-relevance-magnet-strength-qts.html
...so I assume the reason it was smooth (relative to the Fostex and the various loose / boombox drivers I tried) is the relatively stiff cone.
I have only tried the vifa TC6 and despite the big boost in sensitivity I didnt like it quite as much as the Hivi driver. A minor nit pick is that top end sounded a bit "paper-ish"
What other drivers have sim'd well for you?
The SN4-60F has a very high EBP (Fs/Qes=112/0.53=211) and a strong motor (Bl=6.3Tm) which are both good for horn loading. A stiff cone definitely helps too. The horn dimensions (mouth area and length) are what determine the lower cutoff frequency. A stronger motor results in a higher sensitivity, if everything else stays the same.
The TC6 has a fairly high EBP (187) but not a very strong motor (Bl=2.14Tm). The FR is pretty smooth up to the peak just below 20kHz. It has a low moving mass and a paper cone so it may not be very stiff because it also looks like the voice coil is <1in diameter.
I haven't actually simulated any yet, just made a spreadsheet with various driver parameters. Here are the top 10 candidates (this is by no means an exhaustive list) in order of highest EBP, then highest Bl:
1. $27 Tang Band W2-748SG
2. $27 Tang Band W2-800SL
3. $18 Tectonic Elements TEBM46C20N-4B
4. $13 Dayton Audio ND64-4
5. $27 Tang Band W3-881SJF
6. $30 Peerless NE65W-04
7. $13 Peerless PLS-830983
8. $19 Fountek FR58EX
9. $15 Peerless PLS-50F25AL01-04
10. $13 Fountek FE85
It's also interesting to note that the top 4 drivers have flat or curved cones, which is probably a good thing to have for horn loading. The Tectonic Elements BMR might be the odd ball because the cone is meant to operate as both a piston and a surface wave radiator.
Because of the small driver size (even with the horn loading) the combination of low sensitivity, low Xmax, and low power handling means most of these will never be able to play very loud. The potential to sound great from 300-500Hz on up at a very reasonable price is still the intriguing part.
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Couldn't find anything else about this size or larger with decent reviews that isn't more than twice as much, so I caved and ordered a pair. My wife probably won't be too happy when they appear in the living room
Now these just need some drivers...Couldn't find anything else about this size or larger with decent reviews that isn't more than twice as much, so I caved and ordered a pair. My wife probably won't be too happy when they appear in the living room
Yeah they are good value horns. Have you decided on a driver/s yet?
Hi,
Do you make a little adapter (coned chamber) between the apex of the horn and the 2.5" cone driver to allow cone surrounds not to touch the 2" (or less) apex?
I'm asking how is the highs roll off with a 2" non tratrix horn VS same driver with 1" to 1.5" apex ?
the lower overture should give more compression, hence a lower mid-bass end and more spl in this area as well ?
sorry if inacurate question, horns are still a mistery for me. I initially purchased a Scan Speak 2.5" 10F/8044 with Neodym magnett and a "strong" BL for such design you are experimenting with (it was for the foam horn of xrq971 I never achieved due to my poor hand skills...)
To sumarize my questions : does it make sens to use a littlier horn apex overture such 1" or 1.5" to make the horn more full range in the highs ?
(and still having a low XO at only one octave of the driver FS as the higher spl thanks to the horn helps to reduce low end distorsion ?)
like the idea to make a poor man sealed Gedlee 2 way (to avoid the mess of synergy construction which ask even more hand skill, but of course at the cost of a less adapted horn shape than Earl's sota shape).
I like the idea with 1.4" to 1.5" overture is maybe the trade off between highs and lows, but again have no idea how a horn is working ! Ultimatly benchmark a compression vs such cone driver at the end of the day !
Do you make a little adapter (coned chamber) between the apex of the horn and the 2.5" cone driver to allow cone surrounds not to touch the 2" (or less) apex?
I'm asking how is the highs roll off with a 2" non tratrix horn VS same driver with 1" to 1.5" apex ?
the lower overture should give more compression, hence a lower mid-bass end and more spl in this area as well ?
sorry if inacurate question, horns are still a mistery for me. I initially purchased a Scan Speak 2.5" 10F/8044 with Neodym magnett and a "strong" BL for such design you are experimenting with (it was for the foam horn of xrq971 I never achieved due to my poor hand skills...)
To sumarize my questions : does it make sens to use a littlier horn apex overture such 1" or 1.5" to make the horn more full range in the highs ?
(and still having a low XO at only one octave of the driver FS as the higher spl thanks to the horn helps to reduce low end distorsion ?)
like the idea to make a poor man sealed Gedlee 2 way (to avoid the mess of synergy construction which ask even more hand skill, but of course at the cost of a less adapted horn shape than Earl's sota shape).
I like the idea with 1.4" to 1.5" overture is maybe the trade off between highs and lows, but again have no idea how a horn is working ! Ultimatly benchmark a compression vs such cone driver at the end of the day !
I was surprised to find that, in a midrange horn, motor strength was not good (or bad) for horn loading.
Keeping everything else equal (same horn and same driver, aside from the magnet strength), the faulty magnet did not change bandwidth, HF rolloff or breakup behavior.
Efficiency was the only thing that changed.
Not yet. I no longer have the free time to knock stuff out in a weekend, so there are no real goals for this, just experimentation and to see what a small driver in a horn sounds like!
An adapter/spacer will definitely be required for any of the drivers where the entire surround does not fit inside the throat. Any volume of air between the driver and the throat will create an acoustic low pass filter. Ideally this volume should be minimized to reduce the HF rolloff.
I don't yet have any practical experience with horns; only theoretical knowledge from lots of reading about the design experiences/results posted by other kind folks and some time spent simulating designs in Hornresp. Using a horn with a 1" or 1.4" throat is certainly an option. bushmeister did this in the XBush design with the SB65WBAC25 2.5" driver and XT1464 1.4" ESS horn and the results look great.
A driver with a weaker motor could be a great match for horn loading under the right circumstances. The strong motor recommendation is just a general guideline, not a hard and fast rule. It certainly doesn't hurt that stronger motors result in higher efficiency/sensitivity. I prefer to use smaller amps that waste less energy to be environmentally friendly
The horn controls the lower frequency cutoff and the directivity, so as long as the driver is decent and is operated within its limits the results should be decent.
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Thanks BWRX,
I'm asking myself how you are all making your throat adapters for such cones !
Anyway, I saw Bushmeiter's Elipson look sauced à la Synergie ! Very impressive ! Not for me : the way he CNCs that wood balls or planters needs a lot of skill and no simple Tools... Very good job!
Anybody aware of 3D print throat adapter for cone drivers to Horns adaptation ?
I'm asking myself how you are all making your throat adapters for such cones !
Anyway, I saw Bushmeiter's Elipson look sauced à la Synergie ! Very impressive ! Not for me : the way he CNCs that wood balls or planters needs a lot of skill and no simple Tools... Very good job!
Anybody aware of 3D print throat adapter for cone drivers to Horns adaptation ?
Unless I come across a better material to work with, the plan is to use 0.5" or 0.75" MDF to make the throat adapters. Any size circle can be cut with a router and a jig, and then a chamfer or round-over or cove can be cut at the correct depth to accommodate the surround and maximum cone excursion. Sandpaper and/or a file can be used to tidy things up and make the adapter transition smoothly with the horn's throat.
bushmeister used epoxy directly on the driver's frame, which worked well and let him create a completely custom shape. I don't want to do that to a bunch of drivers, and prefer to work with wood over epoxy, plus I already have scraps of MDF that will work well for this purpose.
His spherical enclosure making skills are definitely very good! It would be fun to try, alas it will have to wait
bushmeister used epoxy directly on the driver's frame, which worked well and let him create a completely custom shape. I don't want to do that to a bunch of drivers, and prefer to work with wood over epoxy, plus I already have scraps of MDF that will work well for this purpose.
His spherical enclosure making skills are definitely very good! It would be fun to try, alas it will have to wait
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Thanks for your kind words - can't believe I am embarking on more sphere madness... Funnily enough after blowing one of my SB65s (don't ask how loud I was playing the music!), I did exactly what you are suggesting here and used a hole saw to make a 6mm MDF spacer. Worked just as well without faffing with epoxy putty, so your plan is sound!
Picked up the horns yesterday and they look pretty nice for $40 each. The only gripe is with the throat. The throat opening is not a perfect circle, it's more like a square profile that was massaged into something that is almost a circle.
I don't yet have any have any quality 2-3" drivers to test it out with, but I do have some old paper cone drivers from computer speakers that I pressed onto the horn to hear how it sounds. The 3 drivers were from Altec Lansing, Harman Kardon, and Yamaha. The Altecs were in very small sealed enclosures, the Yamahas were in mid size vented enclosures, and the Harmans were probably in small vented enclosures. Anyway, the Altecs and Yamahas sounded pretty bad and the horn just made then sound worse but a lot louder as was expected from the directivity. To my surprise the Harmans actually sounded pretty decent! I spent about 2 hours listening in the basement and going through my music library while this crap speaker was just pressed onto the horn. It is a different sound, and one that is difficult to describe because it has almost no bass output, but I was honestly a bit shocked at how decent it was. I played everything from Tito Puente's El Cayuco to rock to rap to classical to techno to whatever and enjoyed most of it. It did make certain tracks sound better and certain tracks sound worse, compared to what I'm used to hearing, which is a simple pair of JX92S's in sealed enclosures. Regardless, I'm excited to hear some better drivers mounted in this horn and maybe try to pair them with the JX92S's for more of the full range experience.
I don't yet have any have any quality 2-3" drivers to test it out with, but I do have some old paper cone drivers from computer speakers that I pressed onto the horn to hear how it sounds. The 3 drivers were from Altec Lansing, Harman Kardon, and Yamaha. The Altecs were in very small sealed enclosures, the Yamahas were in mid size vented enclosures, and the Harmans were probably in small vented enclosures. Anyway, the Altecs and Yamahas sounded pretty bad and the horn just made then sound worse but a lot louder as was expected from the directivity. To my surprise the Harmans actually sounded pretty decent! I spent about 2 hours listening in the basement and going through my music library while this crap speaker was just pressed onto the horn. It is a different sound, and one that is difficult to describe because it has almost no bass output, but I was honestly a bit shocked at how decent it was. I played everything from Tito Puente's El Cayuco to rock to rap to classical to techno to whatever and enjoyed most of it. It did make certain tracks sound better and certain tracks sound worse, compared to what I'm used to hearing, which is a simple pair of JX92S's in sealed enclosures. Regardless, I'm excited to hear some better drivers mounted in this horn and maybe try to pair them with the JX92S's for more of the full range experience.
For those interested, here are some actual measurements of the eBay horn, not including the ~0.25 in protrusion at the horizontal centers.
The mouth is 16 in (40.64 cm) by 9 5/16 in (23.65 cm), which puts the mouth area at 961.2904 sq.cm. The axial length is 11 7/16 in (11.4375 cm).
I don't have any tape rulers to try and measure the expansion, but I'll try to come up with at least a few points so this can be more accurately modeled.
The mouth is 16 in (40.64 cm) by 9 5/16 in (23.65 cm), which puts the mouth area at 961.2904 sq.cm. The axial length is 11 7/16 in (11.4375 cm).
I don't have any tape rulers to try and measure the expansion, but I'll try to come up with at least a few points so this can be more accurately modeled.
Me and some friends were pretty shocked how good a cheap full range driver in a horn could sound too
Do you plan to build a system around it at some point? Or vandalise the horn with some entry ports for small woofers a la synergy?
If the results with some better drivers are good the horn will most likely get paired with another driver from ~3-400Hz down. There are so many decent drivers to choose from, but I've narrowed down my list to the Tectonic Elements TEBM46C20N-4B, Peerless NE65W-04, and Fountek FE85 or FR58EX. They're cheap enough that it might be possible to get all 3 for testing
The Synergy option has definitely crossed my mind but I'm not up to speed on working out the design requirements or even simulating a multiple entry horn in Hornresp. That will be a later project unless someone else comes up with a cost effective kit first.
The eBay seller (zxpc) said he would contact the manufacturer to try and get more details about the horn. It's doubtful he will get a response, but it never hurts to ask.
The Synergy option has definitely crossed my mind but I'm not up to speed on working out the design requirements or even simulating a multiple entry horn in Hornresp. That will be a later project unless someone else comes up with a cost effective kit first.
The eBay seller (zxpc) said he would contact the manufacturer to try and get more details about the horn. It's doubtful he will get a response, but it never hurts to ask.
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