Whipped up a budget (~$100) 2-way for my cousin

[Chaz H]

My cousin wanted to build a set of speakers and asked if we could make something for around $100, excluding cabinet materials. Here's what I came up with. The drivers are the SB acoustics OEM 6" woofer and the Hi-Vi K1 tweeter; total cost for drivers is a little north of $60. Budget crossover components from Madisound keeps the whole package to just about $100. Given that it's likely the Qts on these woofers is higher than advertised, and the fact that we're using very low-gauge, high-resistance coils for the woofers, I suggested that he first try keeping the speakers sealed. The crossover is 2.1k LR4.

 

[Lojzek]

For a XO filter total of $40,90 you can do better with steel
laminated core(15AWG), Bennic BP caps, air core inductors
(0,1;0,2mH) and cement resistors.

https://www.madisoundspeakerstore.com/steel-laminate-15-awg/steel-laminate-2.0-mh-15-awg-inductors/

 

[Chaz H]

Caps are bennic, small coils are air core, but the big steel core inductors cost a kingly $2.00 more each. 🙂 Actually, I chose the small gauge air core coils because I decided the loss of sensitivity wasn't a big deal and that even a cheap air core might function better than a cheap iron core. Is there any truth to that?

https://www.madisoundspeakerstore.com/air-core-19-awg/madisound-2.0-mh-19-awg-air-core-inductor/

 

[Lojzek]

Simulate with the values of 0,9 ohm (air core) and 0,15 ohm
(steel) and see what it does to bassmid's spl.

I don't think any serious manufacturer would ever choose
an air core over steel in a case like yours.

 

[Chaz H]

I did; I started from the assumption I would use an iron core. The difference in SPL is subtle, basically a little more midrange presence. Frankly I think any additional money would be better spent on a higher quality capacitor for the tweeter.

 

[Dave R]

Looks like a decent outcome.

I've used the K1 tweeter before (5 or 6 years ago), but didn't want to crossover below 3500, based on the impedance peak. The ones I used had Fs around 1400 hz, IIRC (different than the 800 published). Here's the current manufacturer's spec page.
Overview of K1 Drivers_HiVi,Inc

Nonetheless, the tweeter is probably built to hold up. For the price, it's tough to beat.

Nice job. 🙂

 

[Chaz H]

The biggest compromise in this design is indeed the low crossover point. I saw on zaph's page that the Fs is higher than published so the impedance profile I used has a ~12ohm peak near 1200hz. I figure that's close enough for a project like this one (my cousin's not going to be listening to these too critically, so a little more distortion won't matter much so long as the tweeter doesn't explode). Did you cross 2nd order or higher?

 

[Dave R]

Did you cross 2nd order or higher?

Yes, It was 2nd order on both woofer and tweeter.

 

[Chaz H]

A few weeks on, and my cousin has been hard at work. Here are a few pictures of the finished product. One thing is for sure, it's an attractive and unique speaker! I'll bet it sounds great for the price although I do wish I could have made measurements and double-checked the crossover values.

My cousin is a woodworker and has a website: Hastings Brothers Furniture Co.. Now that he's gotten some practice, I'm sure he'd be happy to do custom cabinets for anyone who's interested in the Chicago area.

 

[PB2]

I don't think any serious manufacturer would ever choose
an air core over steel in a case like yours.

For cost perhaps yes, but he asked about performance.
PSB Stratus Gold has all air core inductors, even the AR3A, most
vintage AR speakers had all air core.

Very nice work, you should do an MTM or MMT version in a tower format
vented to about 32 Hz - if you like. You've got enough tweeter
sensitivity for it.