simplest speaker crossover

[soundnovice]

hi all,
in its simplest form (neglecting sound quality) can i just connect a suitable capacitor in series with tweeter and give power amp output to the drivers directly? which cap is to be used? polar or non-polar

thanks,
Rranam

[ODougbo]

Series, non polar, but there are inexpensive pre made crossovers that you might be interested in.
http://www.mcmelectronics.com/product/50-784
Never neglect sound quality – chuckle

[chrisb]

provided there isn't extensive overlap in the FR, and the mid-bass driver's HF roll-off is not too hashy, there's no reason a simple cap wouldn't be worth a try - which certainly makes spending a bit more on nice film caps worth considering.

[CharlieLaub]

Sadly, this is how many super cheap commercial speakers are designed. This gives the minimum protection to the tweeter and you are listening to the woofer's breakup...

But, on the glass half full side of the coin, it IS possible to pull this off in a halfway decent fashion if (a) woofer breakup is benign, and (b) the tweeter can handle the extra power and low frequency content that will still reach it.

Typically this would mean a circa 6" poly cone woofer, and a ferrite magnet tweeter with a 2.5-3.5k Hz resonant frequency and a very low impedance peak.

There will still not be any baffle step correction or any other circuitry to shape the frequency response, remove peaks, etc. But I have to admit the very first speaker I ever built using some drivers from RadioShack had a single cap in series with the tweeter. It was used in a bookshelf, which acted like a huge baffle. I recall that it didn't sound half bad!

-Charlie

[technofreak]

Hi,

Surely, it can be done, and the results can be rather good - but you need to choose your drivers carefully. Paper or poly midrange with minimal breakup and smooth roll-off is most important. For tweeter, though, I´d suggest 2. order crossover with somewhat smaller cap and larger coil than textbook suggests - experimentation and measuring is the key. 1. order x-over doesn't work very well for tweeters, IMHO. If you choose right drivers you can actually get true acoustic 2. order roll-offs for both mid and tweeter.

I've done it myself with Eminence Alpha 6 mid and Celestion HF-50 tweeter in a 3-way setup - no passive crossover for Alpha (4. order L-R active highpass filter at around 300 Hz); 4,7 uF cap in series and 0,22 mH inductor parallel with the tweeter. Acoustical crossover point is around 5,5...6 kHz. Sounds very good, almost like a good fullranger. Before that I tried different solutions - 1. order for both drivers; mixed 1. order for Alpha - 2. (even 3.) order for Celestion; no crossover for Alpha - 1. and 3. order for Celestion; different values and attenuation resistors... In the end, second simplest solution (2. order with non-textbook values and no padding resistors) worked the best.

The trade-off of this kind of setup is bad vertical polar response - the x-over point is necessarily high, and this shows.

[speakerdoctor]

Originally Posted by technofreak

Hi,

Surely, it can be done, and the results can be rather good - but you need to choose your drivers carefully....

Surely it HAS been done by Burhoe many years ago with the very successful EPI 100 speaker. Just a 10 uF cap in series with the tweeter and that's it. The formula for success is as you pointed out: picking the right drivers that can handle themselvels in that kind of environment.

The circs 1990 Sonus Faber Extrema approx. $12,000 speaker came close with just a resistor in series with the tweeter and parallel coil and a coil in series with the bass/mid.

[CLS]

If you haven't bought the drivers, yet, then I'd suggest skip the multi-way configuration and head for a decent wide-ranger.

(Eventually, the cheap solution might probably cost you much more then expected.... )

If you got all the drivers on hand already, then take a look at this site:
Loudspeaker Design Software

I found it easy to use and very accurate if the impedance data is available.

Driver's impedance data can be obtained from measuring tool like WT3. It's a good tool and worth the money. Very useful if you are going to stay in this hobby.

[bambadoo]

Do a search for ar-sxo. 2 coils and 1 resistor. Have used it and it was splendid.
Reference 3a did a speaker with just one cap if my memory serves me ok...

[soundnovice]

thanks to all.
i have already bought following drivers.

Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

and i am building exactly same speaker as in the following link,
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories

AR-SXO seems to be the simplest possible solution for me compared to the one given in the above link.

i have one more question.
what are your thoughts on active xover? i am planning to use LR4 xover ckt as in below link,
Linkwitz-Riley Electronic Crossover

which would give better results? passive or active? or in other words which one would suit more for the drivers i have chosen?

thanks,
Pranam

[Moondog55]

I would advise just building the design given by Visaton, reinventing the wheel can be fun but really it is quite a simple XO All things considered that is