Aiyima Express - small 2-way using AliExpress drivers

jr@mac

Long story short, this is a design using those schnazzy copper nipple tweeters and "ceramic" 4" woofers. 0.25 cubes, tuned to 56Hz for an F3 of 49Hz. 4db BSC.

My goal here was to hit a more or less ideal 4th LR alignment. I rarely do that any more, and I gotta admit it was fun watching the reverse null reveal itself. As flat on-axis as possible given the lack of diffraction control. Not excellent off-axis, but should anyone ever build these the intended use is in the near-field as more or less full range monitors. I know off-axis still matters in the nearfield, but less so.

They sound great, and the bass is surprising. Not very sensitive - had to really twist the volume knob on my poor old APA150 to get them to 90db/1/2M for the distortion sweep:

On-axis and reverse null:

I'll post the crossover later today, I am out of DIY give a shits right now. Put a lot of steps on between my measurement PC, component hoard, and measurement stand. Tired of it.

jr@mac

I wanted the crossover to be as small as I could make it and still use all poly caps, so I used the 250V Vihot brand I stock for just such an occasion:

Here is the schema:

And the impedance:

Modeled extension:

Baffle dimensions are 7" x 10" with no edge treatment, I made that decision based purely out of the fact I placed the tweeter pretty close to the top of the cabinet. Not my best decision, I know better, but whatever. Shit happens. If I had it do over again (and of course we always do) I would have done 7-1/2" x 12" and applied a 3/4" round-over.

Link to the caps I used:

https://www.aliexpress.us/item/3256804218030039.html?spm=a2g0o.cart.0.0.760338daS73p61&mp=1&gatewayAdapt=glo2usa

If nothing else, inexpensive prototyping material. You can get 10 47uF caps for less than $30. I would check with Brad though, he is clearancing out a lot of nice caps.

Link to the tweeter:

https://www.aliexpress.us/item/2251832666420433.html?spm=a2g0o.productlist.main.21.11613756xcrAeM&algo_pvid=5e261dcc-7331-4d10-8b0c-be1813a31e7e&algo_exp_id=5e261dcc-7331-4d10-8b0c-be1813a31e7e-10&pdp_npi=3@dis!USD!27.50!23.1!!!27.50!!@21224cdb16895953216493850d0765!12000034281994321!sea!US!132555799&curPageLogUid=tUloj3I1qBql

Link to the woofer:

https://www.aliexpress.us/item/2251832600831564.html?spm=a2g0o.productlist.main.99.19fc3b50PYKWFf&algo_pvid=537c7347-44ec-44ec-a795-21127e1d8abc&algo_exp_id=537c7347-44ec-44ec-a795-21127e1d8abc-49&pdp_npi=3@dis!USD!65.94!65.94!!!470.00!!@21021d8f16895954923623858d0733!12000030776704720!sea!US!132555799&curPageLogUid=YWQ9vIq1FWmC#nav-specification

8 Ohm version. Currently about $65 shipped for a pair, which is well worth it in my opinion. Very nice midwoofer.

jr@mac

Here are the raw driver responses in-box:

Raw driver responses:

If I had done edge treatments and chamfered backside of the woofer cutout things would have been better. So don't let the tweeter response fool you - it is confounded even further by a gap around it because I cut the hole for a different tweeter with a 2mm larger faceplate so there is a small gap causing some issues as well.

OK, this project was just for fun and to see what I could do with a quickie cabinet and some generic Chinese stuff. All I can say is fear not the imports. They perfomed for me.

a4eaudio

If anyone is interested in using this tweeter, I'd recommend NOT searching for "snazzy gold nipple".