Jan 14, 2011

For less than $30, any good?

I'm always sceptical when it's too good to be true. $19.95 for a Pyle PDS221 1" Titanium Compression Driver and $7.91 for a Pyle PH565 90x40 plastic horn. Well, I figured worse case scenerio, at least I'm limited to $30 loss max. On the other hand, if it sounds as good or better than a $30 tweeter, it opens up new avenues as there just aren't any hifi horns for this amount.

I do believe Pyle is not exactly known for hifi stuff. It's therefore not unsurprising that there are no frequency response plot of the PDS221. The Pyle PH565 horn is chosen strictly on size. With a width of 7 5/8", it fits a 6 1/2" or 8" woofer nicely. I have no room for a 12" wide, let alone 20" horn. In any event, it looks absolutely silly, a 20" wide horn sitting on top of an 8" woofer.

Remember, this is Hi-Fi, not PA. Loudness is not the aim. Fidelity is. As usual, the Tang Band W5-704s of the Oriole is used in this audition. If the Pyle combo is proven usable, other woofers can then be considered.

Impedance Plot

First off, let's have a look at the impedance.

I had to run the sweep a few times, just to make sure I'm not making any mistakes.

Remarkably, the Pyle PDS221 (yellow plot) looks almost identical to the Peavey RX14 (violet plot). Does that mean it will have the same Frequency Response shape as the RX14. It would be a bonus if it does.

Gated SPL Plot

Alas, it is not to be. The PDS221 exhibits a rising response from 4KHz - 8KHz (red plot). The horn cuts off at 2KHz at a rate of approx. 12dB/octave.

While it's possible to crossover at 2KHz, I prefer 2.5KHz at 18dB/octave. They always sound more natural away from the edge.

Is the rising response a cause for concern?

Listening Test

With the Synergy crossover switched to 2.5KHz, I sat down to listen to the PDS221 supported by the W5-704s.

I went through a range of music, from instrumental to vocals. After a while, I found I was suffering from listener fatigue, in particular, acoustic guitars and brass (saxaphone).

It then occurred to me that the cause is the rising response of the PDS221. It resulted in too much emphasis in the highs. It didn't come across as glare or brightness, just tiring to listen to.

Back to my trusted LMS. Inserted a 0.33mH, did a sweep and voila, I got a flat response from 2KHz-5KHz. Now, that looks promising.

Though the PDS221 rolls off at 7KHz, I'm not too unduly concerned.The critical crossover is between the woofer to the compression driver. If that's not right, everything falls apart. A super tweeter can always be inserted later if desired.

With a 0.33mH in place, it sounds perfect now. After a day of music, no fatigue. Would I recommend the PDS221?

Yes, without hesitation. Great value for money. Just remember to cross at 2.5KHz (18-24dB/oct) and insert a 0.33mH air core inductor in series. It's still cheaper than a Peavey RX14.

A word of caution. Take the 300W power rating of the PDS221 with a large pinch of salt. I would not use this driver in a rock band sound system. Pay more and use a RX14 instead.

Mike