Horn & CD Test Sweeps for SLeeperz Project - OmniMic . . .

Steve_Lee

Attaching files for simplicity on my part:

Let me know your thoughts/observations, please.

Steve_Lee

Looks like the mid D250X CD on the Celestion H1SC-9040 Horn XO'd from the woofer @ 800 Hz to the DH175 CD/Horn tweeter combo @ ~ 5KHz will work with a pretty steep loss in output above 15KHz . . . will work . . .

Steve_Lee

After further consideration, this 3 way combo is pointless when the tweeter will XO to the woofer without adding the complexities of the mid horn/CD.

Steve_Lee

Wonder where Drew went after I did all these sweeps just for him to compare notes?

dcibel

If you’re looking for feedback, I have 2 comments. First is that there’s more to horn performance than just on-axis response, you may want to do horizontal and vertical measurements at 10-15 deg interval to 90 degrees horizontal and vertical. Using Omnimic it can generate some polar map for you.

Second is that horn/CD combos often require a fair bit of crossover complexity to achieve hifi levels of response linearity if being done passively. Using active filter / DSP you may still want to pad the tweeter passively to help SNR .

Steve_Lee

Excellent suggestions - especially concerning the passive padding of the CD - I hadn't thought about it but the SNR angle makes perfect sense.

Thanks.

DrewsBrews

Sorry about that. I just saw the post now. Still getting used to this forum format.

I'm surprised the D250x still falls off so early on other horns. I have yet to work with active XOs, but I plan to one day. All my experience is with passive XOs and I'm still learning myself. But, I think it would be hard to work with the D250x if that is how it is going to be.

The DH175 with the factory horn looks smoothest, response wise, to me. Though might want to peek at the distortion graph. I suspect some distortion creeps in as frequency goes lower making it better to cross over higher than the FR graph might indicate.

I'll help how I can, but I might get in over my head quickly too due to my own limited experience. In the end I just wanted to raise awareness of a potential issue before you invest a bunch of time into a build.

Steve_Lee

Thanks Drew - I needed that nudge actually, otherwise I would have blundered ahead and become frustrated.

I will check the distortion on the little DH175 CD/horn next . . . recommended XO is 2500Hz so the distortion is probably pretty rude down around 1300Hz . . . This horn project is looking like a no-go.

But! The Heil AMT and the Dayton PA310-8 Woofer should get along together . . . (I hope).

DrewsBrews

Check out https://ampslab-spk.com/
Helped me tremendously, especially for potential horn/driver pairings and real world testing of woofers.

Also this site is nice to help decide on horns to try https://mtg-designs.com/tips-tricks-tests/waveguide-shootout

Steve_Lee

That MTG-Designs link looks like the stuff!

I also found this link while poking around on AmpsLab (Michael Chua's) site --> https://ampslab-spk.com/pro-drivers-2/

Thanks.

Billet

Have you listened to any of these drivers yet? Graphs don't tell you how a driver sounds, IMO.

Steve_Lee

No, I have not. Good point. Trying to decide how/where to XO them initially using DSP . . . and seeking feedback. Looks like distortion checks are needed next.

DrewsBrews

Here is a combo I found recently. I'm very interested myself. The flattest with most bandwidth I've found sofar for the price.
https://madisoundspeakerstore.com/sb-audience-pro-sound/sb-audience-bianco-44cd-pk-compression-driver-1/

The response appears to have been measured with this horn
https://madisoundspeakerstore.com/audience-horns/sb-audience-horn-h250-250mm-x-250mm/

For some reason, that reminds me.. Have you looked into the econowave project Steve?

Steve_Lee

Wow - the SB CD/Horn response does look good. $205 shipped for the pair . . . hmm . . .
I really haven't spent a lot of time researching the Econowave discussions due to the length and diversity of them.
Would be preferable to make something out of the parts I have rather than tossing them in the trash (my storage shelves for this stuff are damn near full of un-started projects).

Thanks for the links, Drew - good stuff!

Steve_Lee

I found the solution for the horns --> abandon them and get this coax unit - just bought the last pair I could find in the USA --> CELESTION TFX0615 --> https://celestion.com/product/tfx0615/
Even come with a suggested cabinet and XO design --> https://celestion.com/wp-content/uploads/2019/09/TFX0615-Xover-design.pdf

They model well and with DSP look very useable/loud & sensitive.
This will take up very little cabinet volume and place all drivers close together where it counts.

Love it!

Steve_Lee

Great Horn Shootout (For reference):

https://www.mtg-designs.com/tips-tricks-tests/waveguide-shootout

tajanes

I believe I purchased my pair Celestion TFX0615s from Parts Express - no longer listed.

Steve_Lee

I found my pair at Reverb.com - New in box but haven't tried them yet.
What did you think of them?

tajanes

The mid has a dip ~2100 and peak ~5000 that needs work - but dips aren’t as problematic as peaks ( you notice peaks). I didn’t go with the recommended Xover - I didn’t know there was one at the time. It would be a good place to start. I use a dsp ‘overlay’ (to the passive Xover) and the resulting performance is good.

As mentioned in another thread, I prefer the Beyma coax’s with the extended tw horn, but that being said I generally prefer coax over separate tw and mid. And, will be using these Celestion’s in my latest build.

Steve_Lee

I saw that post and was impressed by the crossover in the back of the cabinet and the IB/open back arrangement.
I looked up the FR sweeps on the Beyma and thought it was more ragged than the Celestion.
Anyways - DSP makes all that moot.

I just need to get back into the shop and stop designing in my head . . . and start finishing some things I started . . .

6thplanet

That's a great shoot out! Glad the Eminence H290S's I bought were a good performer. Having that test will allow someone to easily find the right horn/waveguide to match their project a lot easier.

tajanes

@Steve_Lee said:
I saw that post….

When I get around to the crossover revisit, I’ll probably start with looking at / and measuring their recommended design, and see how it handles the mid and tw (separately and in combo). I’d like to also take a run at just setting a passive notch for the 5000 area on the mid, and seeing how ‘simply’ I can bring in the tw with a HP filter. As per Notch-Filter Crossover, pg 97 ‘Desiging, Building, and Testing Your Own Speaker System’ David B. Weems 4th edition

Let me know what you find / try in your design- thx.

And ‘designing in my head’, and may I add with lots of graph paper, saves a lot of sawdust, and is the fun creative part IMO.

Steve_Lee

FYI - I almost bought a pair of 12" deep 2" throat horns 18" X 10" and some 2" CD's because it can cross below 500 Hz but then realized I have no place to use these monsters when a 5 ~ 6" cone driver can do the same thing in a smaller space for less money - but it is sooo tempting to try them anyways --> http://www.zxpc.us/category-s/195.htm

tajanes

I agree. Never built, but very tempting...

Steve_Lee

Ooooh!

Steve_Lee

Since I already have a pair of TPT-D250X midrange CD's and I saw this cheap as heck horn, I couldn't resist --> https://www.parts-express.com/BL-409-Plastic-Horn-Waveguide-299-2327?quantity=1
and, you also get 12% off today (Just something to play with to increase my knowledge/understanding . . .)

DrewsBrews

Those things are ginormous. I got a pair a while ago, but haven't done anything with em yet. For $4 seemed worth it to have some fun playing around with.