Midrange horn driver options

[jrh0516]

Hi all I'm looking to design a midrange horn for home use. Any links to previous designs to get me started? I'm interest in what type of drivers work well in these applications. Cost is a concern. Although this is my first post here, I've designed several speaker with horn response, Xsim, PCD, etc.

I've seen Bill W's synergy horn, but looking to do mid range only. Roughly 700 to 4,000 Hz, maybe 90 dB at 2.83v. Probably 15 inch on the bottom and SEOS12 on top

John H

 

[Pano]

Compression driver or horn loaded cone?

 

[jrh0516]

Don't know could go either way. However based on keeping costs down, and home use, seems like a horn loaded cone would be best. A rectangular throat adapter for a cone seems like it might be a bit easier to build.

 

[Pano]

OK, thanks for the info. If you hunt around a bit, there are a number of posts that show the little Vifa/Peerless TC9FD is very clean in a front horn. Not a bad place to start.

Peerless by Tymphany TC9FD18-08 3-1/2" Full Range Paper Cone Woofer

 

[jrh0516]

Thanks. I've got some of the TC9s to give it a try if I get that far. Looks like I'll be spending some time with horn response in the coming weeks.

 

[ICG]

The Selenium D250-X GW works nicely and isn't very expensive (for a compression driver).

 

[hottattoo]

jrh0516,

If you want to experiment with an excellent compression drive / horn for fairly cheap, go on ebay and get a pair of EV dh1a's drivers and 940 horns. These are "old school" but offer real high performance, high efficiency, excellent sound and will easily cover the frequencies you desire. Google the driver / horn specs.

 

[Pano]

I'm curious about why you want a horn loaded mid with only 90dB/W
Is it for directivity control? There are plenty of direct radiators that could fit the bill.

 

[jrh0516]

Some good ideas, thanks. I will look at some premade horn/ waveguides.

John H

 

[jrh0516]

I guess the the main reason is I've never done/ used a mid horn.

Thing two was to learn a bit more about modeling a mid range horn. Third was to see if I can be inspired create something like the the JBL L300 Summit or some of the older Klipsch Heresy.

Directivity matching could be a consideration, but I'm thinking that's a detail for later.

 

[djn]

This would be a great start. Go with a good 12 or 15 woof, a MINIDSP, and a couple amps.

http://www.diysoundgroup.com/plastic-seos-12/seos-12.html

 

[ICG]

The horn hottattoo was speaking of is the EV HP940, I guess I should mention that because I think it makes it much easier to find it.

 

[hollowboy]

When you say 'design', are you happy to build around an existing object or do you mean you want to build the horn flare yourself? If the latter, what is your workspace & equipment?

Is there an aesthetic you are after or an existing speaker you'd like to ~clone?

Have you already downloaded and played with Hornresp? [EDIT - sorry, you have, I didn't read proper]

Passive or active crossover? In my experiments, a small cone driver + horn = raw response with too much midbass, needing a shelf of ~5dB at 2kHz. Much easier with a DSP.

90dB and 700Hz-4kHz are pretty easy targets.

Something cheap and generic like this works fine with either a small cone driver or compression driver. I got a pair for some old JBL CDs, but some surprising cone drivers worked well on them, including some awful looking 2" things from a home theatre. The TC9s would go < 700Hz on this.

11" x 17" ABS 2" Bolt-On Long Throw Horn 90° x 40° For Many 2" Exit Driver | eBay

This was built around an Ikea item SEKIN Serving bowl, birch and 4" drivers. The TC9s might be better.

http://www.diyaudio.com/forums/atta...7d1448710816-horn-fast-timber-imag1174-1-.jpg

Again, baffle layout like this = best with a DSP, for delay.

http://www.diyaudio.com/forums/atta...conical-horn-round-vs-round-axis-p-darker.jpg

dark blue = P Audio
pale blue = Fostex

 

[Pano]

I guess the the main reason is I've never done/ used a mid horn.

Thanks, I figured that might be it. Looking forward to seeing what you come up with. Of course I'd rather hear it, but will settle for seeing it. 😉

 

[jrh0516]

When you say 'design', are you happy to build around an existing object or do you mean you want to build the horn flare yourself? If the latter, what is your workspace & equipment?

Is there an aesthetic you are after or an existing speaker you'd like to ~clone?

Have you already downloaded and played with Hornresp? [EDIT - sorry, you have, I didn't read proper]

Passive or active crossover? In my experiments, a small cone driver + horn = raw response with too much midbass, needing a shelf of ~5dB at 2kHz. Much easier with a DSP.

90dB and 700Hz-4kHz are pretty easy targets.

Hollowboy, I'm happy to use someone else's design especially if I can reverse engineer it in horn response. 🙂 I've got a bit of a learning curve in HR. I've only done TLs and taped horns.

The premade horns look like a great way to play around with a mid horn for cheap.

Yeah, down the road a wooden horn flare would look great. I can draw it in AutoCAD, and cut flares on my band saw, just need some confidence that I'm not wasting a bunch of time.

I'd likely do passive x-o, as I'm comfortable with them and like the portability.

I hope the "easy" target helps me through the learning curve. First try had a 90 to 1 compression ratio on a DSA115-8 driver 🙁

 

[hollowboy]

Hollowboy, I'm happy to use someone else's design especially if I can reverse engineer it in horn response. 🙂 I've got a bit of a learning curve in HR. I've only done TLs and taped horns.

For midrange front horns, HR gives good info about the lowest octave. At the help file explains, HR models the driver as an ideal piston - so a real driver is usually much more extended but also rougher than HR predicts.

Two HR things I find useful but which are non obvious:

1) HR does Exp(onential) Con(ical) and Par(abolic) shapes by default, just by clicking. Different profiles, like Oblate Spheroid, are modeled by clicking in that box then hitting a key (O for Oblate, L for Le Cleach etc).

2) From the schematic view, file-->export-->horn data gives some handy options for making a 3D horn with 2D materials.

I'd likely do passive x-o, as I'm comfortable with them and like the portability.

Probably easier with a cone driver, then.

The purple line in post 4 in this thread is the 4" P Audio on the cheap ebay horn I linked to earlier. This is with sharp (DSP) crossover slopes but (looking at the black line) you can see it'd be OK with a shallower slope.

That does the range you want + an extra LF octave.*

By contrast, the 2" compression driver I tried needs more 10dB more Eq to be flat from 700Hz - 4kHz.

This was measured at the horn mouth, so is a lot smoother than the last image I linked to.

better graph

*the 4.5kHz notch was an artifact of the the cavity between the 4" driver and the 2" throat. Adding tiny dots of dense foam to break up the symmetry of that space largely removed the notch, so the combo could be stretched to cover 300Hz-6kHz.

 

[jrh0516]

I don't mind CDs here a pic of my Selenium D220Ti w/ SEOS 12. It's measured, over raw, over sim in Xsim.

Looks like I'm off to find some plastic horns. I've some PE credit to burn, maybe:

PRV Audio WG45-50 2" 90 x 40 ABS Waveguide 4-Bolt

 

[GM]

Roughly 700 to 4,000 Hz, maybe 90 dB at 2.83v.

Same as the pioneers determined, 1" exit compression driver on 500 Hz or larger horn or 350 Hz or larger WG.

GM

 

[hollowboy]

I don't mind CDs here a pic of my Selenium D220Ti w/ SEOS 12. It's measured, over raw, over sim in Xsim.

That's way more patience / skill with crossovers than I have.

Re what GM said: maybe look at the specs of some phenolic diaphragm drivers, if you haven't already.

e.g. PRV Audio D250Ph-S 1" Phenolic Horn Driver 8 Ohm 1-3/8"-18 TPI

Frequency Response at -10dB: 400-8000Hz

The 2" horn you linked does look good if you wanted to try small cone drivers vs compression drivers.

 

[GM]

+1 looks good, especially for a large WG, which is what's ideally needed for this BW. I assume Bill's Synergy horn designer has inputs to allow different aspect ratios, horn cut-off specs and use HR or similar to proof/fine tune it.

GM