That looks like one of B&G Radia Neo8 copies. More a mid than a tweeter. Excellent for dipole multiways! Distortion graphs would be interesting to see.
A single mid in the entire horn is going a wee bit too far for my taste but I can definitely see a benefit in cutting back from four mids to two.
Here is graphic exported from the Sketchup of my Synergy corner horn design.
The grey shapes are the footprints of the mids as I built. The yellow footprint shows where I would put a single (4FE35) mid. As you can see, the single mid would allow the ports to be perhaps .5" closer to the apex, which would allow me to push the crossover up above 1.2 Khz, limited by the 1/4 lambda port spacing rule, from its current 950 Hz. The cost would be 6 db of headroom, limited by the Xmax of the mid, which plays down to 200 Hz. But I can hit 120 db at 200 Hz at Xmax so I can afford to give up those 6 db.
Of course the ship has already sailed, but there is always a next time and I still need to cut and build the 2nd of my stereo pair.
Here is a link to my design/build thread, currently a work in progress
http://www.diyaudio.com/forums/multi-way/291160-my-synergy-corner-horn-bass-bins.html
Here is graphic exported from the Sketchup of my Synergy corner horn design.
The grey shapes are the footprints of the mids as I built. The yellow footprint shows where I would put a single (4FE35) mid. As you can see, the single mid would allow the ports to be perhaps .5" closer to the apex, which would allow me to push the crossover up above 1.2 Khz, limited by the 1/4 lambda port spacing rule, from its current 950 Hz. The cost would be 6 db of headroom, limited by the Xmax of the mid, which plays down to 200 Hz. But I can hit 120 db at 200 Hz at Xmax so I can afford to give up those 6 db.
Of course the ship has already sailed, but there is always a next time and I still need to cut and build the 2nd of my stereo pair.
Here is a link to my design/build thread, currently a work in progress
http://www.diyaudio.com/forums/multi-way/291160-my-synergy-corner-horn-bass-bins.html
Attachments
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Ok so the monsoon rains stopped long enough for me to get outside and do some measurements over the weekend. Here are the 2m ground plane response charts.
Did the trick with a spare silk dome tweeter as reference impulse to do time alignment on the drivers. Realised last night that one of my woofers was wired incorrectly- so woofer chart is of a push pull config...😱
I can upload the MDAT files for the woofer/mid but the CD file is too large (even if I zip it...)
It appears as though my mids are lacking enough motor strength to get them to the CD xo point (1300hz). I've already added frustrums and reduced the cone volume but they are still struggling. Response worsened when I taped over one of the mid ports on each driver with roll off occurring earlier. Woofer sensitivity is probably messed up due to the incorrect wiring (I reduced the gain 3db on the DSP once it was fixed).
Not sure where to go from here. I've got crossovers set on my mini dsp 4x10 set as the following
Woofer- 75-250hz LR 48DB/oct (high and low) +5db gain
Mid- 250-1000hz LR 48db/oct (high and low) -7db gain
CD- 800-20K LR 48db/oct (high pass) -15db gain
Any thoughts?
Mark
Did the trick with a spare silk dome tweeter as reference impulse to do time alignment on the drivers. Realised last night that one of my woofers was wired incorrectly- so woofer chart is of a push pull config...😱
I can upload the MDAT files for the woofer/mid but the CD file is too large (even if I zip it...)
It appears as though my mids are lacking enough motor strength to get them to the CD xo point (1300hz). I've already added frustrums and reduced the cone volume but they are still struggling. Response worsened when I taped over one of the mid ports on each driver with roll off occurring earlier. Woofer sensitivity is probably messed up due to the incorrect wiring (I reduced the gain 3db on the DSP once it was fixed).
Not sure where to go from here. I've got crossovers set on my mini dsp 4x10 set as the following
Woofer- 75-250hz LR 48DB/oct (high and low) +5db gain
Mid- 250-1000hz LR 48db/oct (high and low) -7db gain
CD- 800-20K LR 48db/oct (high pass) -15db gain
Any thoughts?
Mark
Attachments
NC535 -
I measured distortion of my horn with the single mid -
Now, the single mid is where the HD is lowest in this design at the moment.
(edit: here are the driver contributions -
)
Except for that HD2 peak for 450Hz. But after a long night of debugging and breaking things, it turned out that that distortion is from the woofers (yeah, a simple test would have turned that up early, but why question an assumption when you can waste an evening discovering that the assumption was bad?).
So, I don't see any reason at all for another mid on this horn. (But I'm not at all interested in 120dB SPL, either, different priorities).
BTW, still trying to understand the 450Hz HD2 peak from the woofers. Their impedance curve does show some irregularity at about 900Hz (resonance in the rubber surround?), would that be expected to result in a measured narrow disortion peak when driven at 450Hz?
I measured distortion of my horn with the single mid -
Now, the single mid is where the HD is lowest in this design at the moment.
(edit: here are the driver contributions -
Except for that HD2 peak for 450Hz. But after a long night of debugging and breaking things, it turned out that that distortion is from the woofers (yeah, a simple test would have turned that up early, but why question an assumption when you can waste an evening discovering that the assumption was bad?).
So, I don't see any reason at all for another mid on this horn. (But I'm not at all interested in 120dB SPL, either, different priorities).
BTW, still trying to understand the 450Hz HD2 peak from the woofers. Their impedance curve does show some irregularity at about 900Hz (resonance in the rubber surround?), would that be expected to result in a measured narrow disortion peak when driven at 450Hz?
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Hi Bill:
My comment about a single mid going a bit too far was more about for my design than for yours. I should thank you for opening up my eyes to the possibility of using fewer mids. I never gave it a second thought until you showed your design.
Your design seems to be balanced SPL capability wise. HD does poke up above that 450 Hz peak at around 100 Hz but that is where most would cross to subwoofers. I do find it curious that the 450 Hz HD2 peak appears to be right where you are crossing from the mid to the woofers. Can that be a coincidence?
My comment about a single mid going a bit too far was more about for my design than for yours. I should thank you for opening up my eyes to the possibility of using fewer mids. I never gave it a second thought until you showed your design.
Your design seems to be balanced SPL capability wise. HD does poke up above that 450 Hz peak at around 100 Hz but that is where most would cross to subwoofers. I do find it curious that the 450 Hz HD2 peak appears to be right where you are crossing from the mid to the woofers. Can that be a coincidence?
A couple of things:
If you can't post the .mdat file, just take a screenshot of the waveforms and a post the image.
I see from your first post that your did ports are 82 mm from the CD screen. I haven't simulated it (have you?) but that sounds a little long to result in a reflection null higher than 1300 Hz, your intended crossover point.
In the simulation you have to allow at least a couple of cms for the distance from the CD screen back to the diaphragm the sound actually bounces off of.
If you can bring your ports closer to the apex of the horn, that might be worth trying, unless you have a simulation that argues otherwise.
It might be related to the woofer crossover affecting it (as I said, the peak doesn't change at all when the midrange is disconnected). I'm about to go downstairs and take a woofer out and look at its distortion shapes running barefoot, see if the peak is still there. I don't see the peak as being a showstopper (it's really too narrow to be much of a concern as long as it isn't from something buzzing or rattling), just a mystery.
Mark, XRK was suggesting the 3 way harsch crossover, with a woofer 4th order LF, Mid 2nd order HP and Lp, and tweet 4th order HP, and the appropriate delays of 1/2 the xo frequency. Worth a listen to compare against your plan above, the transient attack is supposed to be sublime with the harsch.
Sent from my GT-I9505 using Tapatalk
Ok so I've had a stereo pair of these running for a few months now and the limitations of the recycled driver's ive used has become apparent. The mids just don't have the motor strength cant meet the CD XO and the woofers just don't have the sensitivity, power handling, or xmax to match the others in the horn (currently a 20db mis-match between CD and woofs)
It is very tricky for me to get gear where i'm living (Laos) but I have some family visiting soon (and a holiday to Germany so could order something from Thomann or Blue Aran) and can arrange for speaker mules to courier them on my behalf. I'm looking for some advice on drivers for a more dedicated build.
For the mids I'm pretty convinced of the Pyle PDMR5s. I have experience with them from another build and they have held up to mids duty in PA level application really well. In that 60x90 horn they play well to 270hz.
I am a bit lost at looking for some inexpensive- easy to obtain (not from the US) woofers for low mids duty (80-300hz). I can get the 4Ohm Faital pro 10FE200 for quite a good price. Would run 2 per cab for a 8ohm load. It has a good sensitivity to match the other drivers and a decent power handling (this is mainly for domestic use but I do like to drag it outside for rowdy garden parties)
FaitalPRO | LF Loudspeakers | 10FE200
Anyone care to have a look at the TS and let me know if they think it would work? From a glance the motor strength is a bit low...
Fs
55 Hz
Re 3 Ohm
Qes 0.52
Qms 9.2
Qts 0.54
Vas 53 dm^3 (1.87 ft^3)
Sd 332 cm^2 (51.46 in^2)
Xmax (4) 4.62 mm
Xdamage (5) 10.4 mm
Mms 24.8 g
Bl 7 N/A
Le 0.3 mH
Mmd 21.4 g
Cms 0.34 mm/N
Or if you think this i a no-go could you suggest a similarly priced alternative from one of the European webstores?
Thanks!
Mark
It is very tricky for me to get gear where i'm living (Laos) but I have some family visiting soon (and a holiday to Germany so could order something from Thomann or Blue Aran) and can arrange for speaker mules to courier them on my behalf. I'm looking for some advice on drivers for a more dedicated build.
For the mids I'm pretty convinced of the Pyle PDMR5s. I have experience with them from another build and they have held up to mids duty in PA level application really well. In that 60x90 horn they play well to 270hz.
I am a bit lost at looking for some inexpensive- easy to obtain (not from the US) woofers for low mids duty (80-300hz). I can get the 4Ohm Faital pro 10FE200 for quite a good price. Would run 2 per cab for a 8ohm load. It has a good sensitivity to match the other drivers and a decent power handling (this is mainly for domestic use but I do like to drag it outside for rowdy garden parties)
FaitalPRO | LF Loudspeakers | 10FE200
Anyone care to have a look at the TS and let me know if they think it would work? From a glance the motor strength is a bit low...
Fs
55 Hz
Re 3 Ohm
Qes 0.52
Qms 9.2
Qts 0.54
Vas 53 dm^3 (1.87 ft^3)
Sd 332 cm^2 (51.46 in^2)
Xmax (4) 4.62 mm
Xdamage (5) 10.4 mm
Mms 24.8 g
Bl 7 N/A
Le 0.3 mH
Mmd 21.4 g
Cms 0.34 mm/N
Or if you think this i a no-go could you suggest a similarly priced alternative from one of the European webstores?
Thanks!
Mark
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Mark,
Nice work! You are off to a good start - the measurements show pretty smooth responses on the woofer and mids. The CD needs attention to smoothing the transistion with sanding and putty. Every effort should be made for a smooth transition from the CD throat to the horn. You will see the ragged HF response disappear and smooth out as you file/sand/apply putty. Modeling clay is a good place to start to see immediate improvement.
My one concern is the lack of HF extension of the mid to adequately cross with the CD. That's the main problem with a lot of CD synergies is that the mid will fall well below 1kHz and CDs don't like to run below 1200Hz really unless you have one of the larger format ones. The problem is that the distance from the mid injection to the apex is physically limited. Try making the volume filler plug bigger to take up more room. But I don't see how you can cross the mid effectively as it falls at 800Hz.
You might be able to save it by changing to either a 2in format CD to allow tweeter extension down to 700Hz, or try a 2.5in full range driver as the tweeter a la xBush/Trynergy.
http://www.diyaudio.com/forums/multi-way/285030-bookshelf-multi-way-point-source-horn.html
http://www.diyaudio.com/forums/full...ing-trynergy-full-range-tractrix-synergy.html
Nice work! You are off to a good start - the measurements show pretty smooth responses on the woofer and mids. The CD needs attention to smoothing the transistion with sanding and putty. Every effort should be made for a smooth transition from the CD throat to the horn. You will see the ragged HF response disappear and smooth out as you file/sand/apply putty. Modeling clay is a good place to start to see immediate improvement.
My one concern is the lack of HF extension of the mid to adequately cross with the CD. That's the main problem with a lot of CD synergies is that the mid will fall well below 1kHz and CDs don't like to run below 1200Hz really unless you have one of the larger format ones. The problem is that the distance from the mid injection to the apex is physically limited. Try making the volume filler plug bigger to take up more room. But I don't see how you can cross the mid effectively as it falls at 800Hz.
You might be able to save it by changing to either a 2in format CD to allow tweeter extension down to 700Hz, or try a 2.5in full range driver as the tweeter a la xBush/Trynergy.
http://www.diyaudio.com/forums/multi-way/285030-bookshelf-multi-way-point-source-horn.html
http://www.diyaudio.com/forums/full...ing-trynergy-full-range-tractrix-synergy.html
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I think the 10FE200 would do well for you. I've modelled it in the past sealed for that duty - down to 80 hz. A quick sim of a dual driver 135L vented cabinet shows extension to 40 Hz. I've actually had the smaller but similar 8fe200 on the test bench but couldn't quite get it up past the 1 Khz mark I needed for my XO to CD so switched to smaller drivers. From 300 or 400 Hz down, should be a piece of cake.
Nc535- Thanks for the re-assuring comment on the 10fe200! Looks like I'll try to pick up 4 while I'm over in Europe!
Ok so I now have in my hot little hands 8 Pyle PDMr5s and 4 Faitalpro 10fe200's to play around with to make my (dare I say it) 'forever speakers' 😀
Previous issue with the recycled drivers included- mids not able to reach 1.2-1.3Khz for XO with the CD, Woofers sensitivity miss-match, and running out of output/X-max way before the other rest of the system.
For todays viewing I have some REW screens of the Pyle mids. The purple chart is the driver simply mounted to a 12mm ply baffle firing through a 19mm port (no frustrum).
The green chart is of a fairly aggressive volume reducer (It took me a few hours on the belt sander to make it this afternoon- so i'd need to find a more efficient method if I was considering doing 7 more!). It does the trick of raising the passband to a solid 1.4Khz, but at the same time it introduces a few dips (450hz). The cone may be rubbing on the reducer and generating the dips. I can afford to take some more material off it to ensure that is not the case. Would making it out of plaster of paris work? I can imagine it being easy to work with sand paper and a file but would it be too brittle?
I've mucked around in sketch up with some driver arrangements and so far the following looks possible
CD- 1300-20khz
Mids- 350-1300hz
Woofer 80-350hz
Any thoughts?
Previous issue with the recycled drivers included- mids not able to reach 1.2-1.3Khz for XO with the CD, Woofers sensitivity miss-match, and running out of output/X-max way before the other rest of the system.
For todays viewing I have some REW screens of the Pyle mids. The purple chart is the driver simply mounted to a 12mm ply baffle firing through a 19mm port (no frustrum).
The green chart is of a fairly aggressive volume reducer (It took me a few hours on the belt sander to make it this afternoon- so i'd need to find a more efficient method if I was considering doing 7 more!). It does the trick of raising the passband to a solid 1.4Khz, but at the same time it introduces a few dips (450hz). The cone may be rubbing on the reducer and generating the dips. I can afford to take some more material off it to ensure that is not the case. Would making it out of plaster of paris work? I can imagine it being easy to work with sand paper and a file but would it be too brittle?
I've mucked around in sketch up with some driver arrangements and so far the following looks possible
CD- 1300-20khz
Mids- 350-1300hz
Woofer 80-350hz
Any thoughts?
Attachments
Do you know anyone in the dental business? You could duplicate the volume reducers to tolerances within a couple of thousandths of an inch using dental impression materials and dental plaster or stone. These materials are very durable as well.
Nice job on the volume plug.
I had a rubbing problem with mine that showed up as a sharp increase in distortion as volume crossed above a threshold.
Put some lipstick on the reducer where you think it might be rubbing and see if any transfers to the cone.
No reason not to run the woofers up to 450 or 500 if they can get there (without volume plugs which are too much work). I doubt if the Pyles are capable of more than 1 mm or so of linear excursion.
I had a rubbing problem with mine that showed up as a sharp increase in distortion as volume crossed above a threshold.
Put some lipstick on the reducer where you think it might be rubbing and see if any transfers to the cone.
No reason not to run the woofers up to 450 or 500 if they can get there (without volume plugs which are too much work). I doubt if the Pyles are capable of more than 1 mm or so of linear excursion.
Ok so have a prototype 60x90 horn up and running to do FR tests and such.
Closest I could get the ports for the mids (line through center of the 19mm ports) corresponds to 1110Hz wavelength.
The CD response in the 60x90 horn is below- roll off is right at about 1100hz so that is promising.
Also below is a comparison between a Mid with a volume reducer (green) and without (red) in the horn (not just on a baffle). 19mm ports are straight- no frustrums as of yet so hopefully that will smooth out some of the lumps.
The mids roll off at around 300 Hz which is perfect for me to hand off to to the Faital 10fe200. The 10" woofers will be mounted to a baffle with small stand off for the 6mm xmax. It will have the volume of the cone, plus the volume of a small chamber on the side of the horn to fire into, before travelling through 2 ports. This has to be done to keep the depth of the speaker to a minimum. I've seen pill shaped ports and regular circular ports used before. What size should I start at for a 10" ? 2x 32mm ports?
Any tips, concerns given the data so far?
Mark
Closest I could get the ports for the mids (line through center of the 19mm ports) corresponds to 1110Hz wavelength.
The CD response in the 60x90 horn is below- roll off is right at about 1100hz so that is promising.
Also below is a comparison between a Mid with a volume reducer (green) and without (red) in the horn (not just on a baffle). 19mm ports are straight- no frustrums as of yet so hopefully that will smooth out some of the lumps.
The mids roll off at around 300 Hz which is perfect for me to hand off to to the Faital 10fe200. The 10" woofers will be mounted to a baffle with small stand off for the 6mm xmax. It will have the volume of the cone, plus the volume of a small chamber on the side of the horn to fire into, before travelling through 2 ports. This has to be done to keep the depth of the speaker to a minimum. I've seen pill shaped ports and regular circular ports used before. What size should I start at for a 10" ? 2x 32mm ports?
Any tips, concerns given the data so far?
Mark
Attachments
A dip before the bandpass peak shows in a few of the hornresp simulations I have done, you might want to compare your real results again the sims to see how close you are. It is then easier to tweak the parameters in hornresp to see which will reduce that dip, or you can try the cut it and see method!
20% of Sd for port size to avoid chuffing is a good recommendation that would be 2 x 65mm ports for the 10FE200, it is also a good idea to allow more clearance than just xmax if you can (Xdam is 10.4mm), you can route a ring into the baffle board as well as use a spacer, routing into the baffle will help to reduce front volume slightly but that is less of an issue for 300Hz and below.
@fluid-Thanks for the contribution!
Good tip on the Woofer xmax/xdamage clearance. I've found routing the cone clearance into the baffle to be a bit of a pain in the past, so I might just us some 12mm ply for the mounting ring instead.
2x 65mm ports for each of the 10" woofers seem pretty large! The ports will be into the 60 degree face of the horn, If I was to do as you suggested there would be less than 65mm between each woofer ports on the left and right hand sides. I might go with the pill shaped ports so I can keep them closer to the corners of the horn. I might start small and just work my way up until I get a good result.
As you picked up I'm a bit more of a cut it up and see kinda audio guy instead of the considered simulator! 🙂
That being said I finally bit the bullet and tracked down a place that sells spade terminals, wire, and automatic wire strippers (which are a damn revelation!) so my ability to quickly modify and measure has improved somewhat.
Mark
Good tip on the Woofer xmax/xdamage clearance. I've found routing the cone clearance into the baffle to be a bit of a pain in the past, so I might just us some 12mm ply for the mounting ring instead.
2x 65mm ports for each of the 10" woofers seem pretty large! The ports will be into the 60 degree face of the horn, If I was to do as you suggested there would be less than 65mm between each woofer ports on the left and right hand sides. I might go with the pill shaped ports so I can keep them closer to the corners of the horn. I might start small and just work my way up until I get a good result.
As you picked up I'm a bit more of a cut it up and see kinda audio guy instead of the considered simulator! 🙂
That being said I finally bit the bullet and tracked down a place that sells spade terminals, wire, and automatic wire strippers (which are a damn revelation!) so my ability to quickly modify and measure has improved somewhat.
Mark
No problem 🙂
It's not really small for a 10" woofer, by making them smaller you increase the compression ratio, limit the maximum output and maybe increase distortion.
This is what two 65mm diameter ports looks like on a 230mm circle which looks to be about where the surround is. Maybe a picture of your horn would make it easier to see why they would be difficult to fit. The streched hotdog type ports can also be easier to fit, as long as the area is the same they will work the same.
Nothing wrong with that! Hornresp is good and might tell you where to look to flatten out the dip. Varying port length and front chamber volume in a simulation is a lot easier that cutting and filling wood.
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