2 way mini bookshelf w/bose fullrange and HiVi tn28

[ching0n]

So I had a pair of the pictured pioneers laying around and was disappointed with the performance in the lower frequencies. I thought I could improve on it and make a good set for a SET tube amp. I chose the bose full range driver based on the TS parameters found at parts express. The problem I'm having however is that the sound is horribly shrill between 2-4khz. I have not installed a low pass filter since I'm awaiting the tweeters; however the crossover point for the high pass (lowest recommended being 1800hz) is going to leave a big gap in that range.

I opted to get genuine bose drivers (from a car) since they were way cheap and didn't have to wait (unlike P-E). Perhaps the characteristics of the bose are worse than the P-E replacements?

Parts Express Parts Express Replacement Speaker Driver for Bose 901 4-1/2" 1 Ohm : Questions, Answers, How To, FAQs, Tips, Advice, Answers, Buying Guide

[kevinkr]

May need a shallow notch between 2 - 4kHz to make these sound right..

Do this with a parallel LRC network in series with the "full range driver."

Edit: Bose makes a lot of different 4" drivers, not sure that you can safely assume that the car drivers are anything like the ones being sold by Parts Express. Variants I am aware of include ones with 1,2,4, and 8 ohm voice coils, with and without magnetic shunts, different cone material formulations, and different spiders.

[ching0n]

this is a 1 ohm driver w/a cloth surround (unlike the foam surround of the 901's and PE's). Paper cone w/o doping (unlike the 151's)

I've heard of impedance mismatch affecting tone (although I am not sure how); my test amp is a ss rated to run 4-16 ohm loads. I figure since the drivers are relatively efficient and am only cracking the vol. 1/4 of the way, it wouldn't hurt anything.

[planet10]

I have 2 pair of those Pioneers. I didn't listen to them much stock, but EnABLed they sound fine. You are never going to get much bass out of a 3" driver.

dave

[ching0n]

Originally Posted by kevinkr

May need a shallow notch between 2 - 4kHz to make these sound right..

Do this with a parallel LRC network in series with the "full range driver."

Edit: Bose makes a lot of different 4" drivers, not sure that you can safely assume that the car drivers are anything like the ones being sold by Parts Express. Variants I am aware of include ones with 1,2,4, and 8 ohm voice coils, with and without magnetic shunts, different cone material formulations, and different spiders.

I've tried two different crossovers (left overs from something) and did see an improvement. Granted these are not sized for the application.

One was a car crossover (what looks like a 2nd order Linkwitz-Riley)...I think it was sized for 4 ohm loads; 2x10uF caps, a big ceramic resistor and two identical inductors of unknown value.

The other one came from a home speaker, looks like a 2nd order xover....10&12uF caps, different sized inductors sharing a single ferrite core and big resistor like the other one.

The 1st one had less bass than the 2nd one, but the 2nd one's bass was too boomy. I guess i'll salvage the car xovers' circuit boards to fit my application; but I'm still affraid of the tweeter's Fo being so close to the xover point. Any advice?

I was initially hoping to just have a high pass filter (cap on tweeter) and that's it.

[cats squirrel]

regardless of any other problems, how are you going to drive the driver, at 1 ohm, volts and amps are the same value!!! Surely, these drive units were meant to be used in multiples?

[ching0n]

yes, parallel array of 9 I think. I've gotta read up on impedance mismatch I reckon, but my luxman seems to be doing ok....should I stop before I burn something?

[ching0n]

Originally Posted by kevinkr

May need a shallow notch between 2 - 4kHz to make these sound right..

Do this with a parallel LRC network in series with the "full range driver."

Thanks; for posterity:
Car Audio - Parallel Notch Filter Circuit for Speaker Design

Now i just need to take some frequency response measurements. Any recommendations for quick and dirty freeware?

[wintermute]

I'd definitely recommend holmimpulse!

Tony.

[ching0n]

Originally Posted by wintermute

I'd definitely recommend holmimpulse!

Tony.

can you use any run of the mill microphone? I'm having a hard time finding calibration procedures for something other than certain units.