Kids' Boombox Driver Choices

[CarlosT]

I'm building a powered kids retro cabinet in a classic SBB4 alignment and have two very different drivers that will work in the same box and here are my two options:

1- Audax 4 ohm full range coax (simple cap built into the tweeter)

http://www.madisound.com/pdf/audax/vp130g2.pdf

2- Vifa 8 ohm midwoofah (no crossover/no tweeter)

http://www.madisound.com/pdf/vifa/mg14wk09-08e.pdf

Which one would you choose? The astounding response of the Vifa but only up to about 5-10kHz or the full-range but response-marred Audax? Why?

Thanks.

[FullThrottleRic]

Can't you put a cheap tweeter with the Vifa? (btw it's more like a 6" driver than and 8" ) I wouldn't run that full range as it has no real high frequency output, what little is there though looks like it wouldn't be too horrible to listen to as the cone breakup looks pretty tame.

Of the two I'd go for the Audax as you could probably go some way to removing the peaks with your own crossover. With the Vifa you can't add the high frequency output that isn't there in the first place.

You have to take manufacturers figures with a huge bucket of salt, so many things can effect how a drive unit measures I've found it's only really reliable to compare graphs of two drivers made and measured by the same manufacturer.

If I were using the Audax the first thing I'd do would be to put a resistor in series with the tweeter to bring it to roughly the same level as the woofer. You could also try reversing the polarity of the tweeter which might get rid of the large dip in the middle of the graph, although I doubt the crossover will be 1st order at ~1.5khz with the look of tweeter used but you never know

The drive unit you've picked there is an automotive drive unit, which are normally listened to a fair bit off axis which would explain the extra high frequency output. As you can see from what I assume is the 45 degree plot on the graph it looks a lot smoother once you get off axis.

[pjanda1]

I think any of these would be good choices, and may well work better for your app. You could consider adding a cheap tweeter to the Vifa. I bet a piezo would do the trick.

The Tang Band is a bit more $$, but with it's large excursion, it should be capable of decent SPL's. It has great extension, works in a fairly small enclosure, and is probably the smoothest of the lot. The Pioneer gets to 13K or so and is smoother than the Coax. Not much Xmax, but not much $$. The MCM is a little more ragged, but I bet it will still be flatter than the Coax, and has an octave on the vifa. It should have a good bit of headroom on the Pioneer, and the price is right.

Tang Band W4-1320SA
http://www.partsexpress.com/pe/showd...number=264-828

Pioneer A11
http://www.partsexpress.com/pe/showd...number=290-010

MCM 55-1870
http://www.mcminone.com/product.asp?...5Fid=55%2D1870


good luck,

pj

[sreten]

http://www.partsexpress.com/projects...uma/index.html

Hi,

look no further than the above for a portable retro boom box.

If its not portable then there is no point in making a boom box
compared to normal speakers, with built in amplifiers or not.

Very good cheap design :

http://www.zaphaudio.com/audio-speaker13.html

/sreten.

[CarlosT]

This is all going into a very small box so I'm running out of space to cut holes. Again I was going for a real simple minimalist approach.

I got some excellent Vifa 3/4" DX19 tweeters on standby though

[CarlosT]

Originally posted by FullThrottleRic
...If I were using the Audax the first thing I'd do would be to put a resistor in series with the tweeter to bring it to roughly the same level as the woofer...

Please tell me a little more about taming this tweeter with a resistor. What value? What type?

Thanks

[FullThrottleRic]

I'd just put a 3w wirewound in and measure it, starting at something reasonable like 3.3ohms and go up or down depending on the relative level.
Make sure you put it on the amp side of the capacitor though, or it will alter the tweeters crossover frequency.

[sreten]

Originally posted by FullThrottleRic

Make sure you put it on the amp side of the capacitor though,
or it will alter the tweeters crossover frequency.

It will change the c/o frequency no matter where you put it, /sreten.

[FullThrottleRic]

Well ok, it will have much less effect on the amp side