Pyle PDB512

Mid/High 1" Titanium Compression Driver

Jan 18, 2011

Pyle PDB512 for $28.33 at Parts Express

The PDB512 is touted as a high power midrange/tweeter compression driver sporting a 1" titanium diaphragm and a 2" flat aluminum voice coil for improved power handling.

I seriously doubt it is capable of it listed power rating of 250W rms. Fortunately in hifi, power is not an issue. More importantly, is it smooth enough to blend in with the other components easily.

Another aspect I'm interested in is the operating range. With a 1" throat, I can safely assume it will not work down to 1,000Hz eventhough the frequency response is listed as 500Hz-18KHz. A true midrange compression driver is one like a JBL2445, a 2" throat monster that weighs in at a hefty 25 lbs, and that is without a horn! Coupled to the right horn, the JBL2445 can operate down to as low as 800Hz.

Like in a lot of budget components, specs are often sparse and whatever are published, are grossly inflated. The PDB512 is no exception. But for the price, how does it fare? Is it marginally usable or a diamond in the rough.

Impedance Plot

Two brand new units of PDB512 were swept from 200Hz to 20KHz.

Generally, they are similar with the exception of the peaks.

In one driver, the impedance peaks at 1,500Hz (green plot), whereas it appears damped in the second driver (violet plot).

If the PDB512 is to be operated below 2KHz, these peaks may have to be addressed.

Let's see what the Frequency Response is like.


Impedance Sweep (200Hz - 20KHz)

Gated SPL Plot

For convenience, I loaded the PDB512 with a Renkus-Heinz metal horn. I don't have the specs but it looks like a CD horn with a 90x40 dispersion pattern.

I was quite stunned by the SPL sweep. I have never encountered such a response before.

The top violet trace shows the response of the PDB512 coupled to the horn.

We can see there's a roll-off consistent with CD horns from 2,000Hz-8,500Hz. After that, it appears to suffer from a severe breakup culminating in a sharp peak at about 11KHz.

Gated Frequency Response Sweep (1KHz - 20KHz)

After overcoming the shock, it struck me that it's quite possible to level the response with a simple CD EQ.

A selection of capacitors from 2uF to 8.2uF was inserted in series with the PDB512 and true enough, a friendly family of plots emerged.

I was tempted to use a 4uF in listening test but it will entail another correction network to tame the rising response from 3KHz-8KHz.

The obvious benefit with the 4uF is with the additional EQ, response is virtually flat from 2KHz-8KHz.

To keep it simple, I decided using a 8.2uF as this value results in the flatest response from 2KHz-5KHz.

I wanted to see how it fares with a few dB loss from 5KHz and whether the untreated breakup at 11KHz is palatable.

Crossing the PDB512

While the PDS221 was crossed at 2,500Hz, I adjusted the Synergy for a slightly lower crossover of 2,000Hz.

I would have liked to cross lower at 1,500Hz but during the SPL sweep, I detected the PDB512 resonanting at that particular frequency.

Looking back at the earlier impedance plots, my suspicions were confirmed. A peak was recorded at exactly 1,500Hz.

To cross at 1,500Hz, a conjugate network will have to be installed to tame the impedance peak. Even then, it is questionable whether it will be of any good as the corner frequency is still at the resonanting frequency.

Listening Test

As before, the Oriole woofer was used for convenience.

From the outset, it was apparent that the lower cross point resulted in a much more distinct midrange. Vocals and instruments now have the presence that was lacking in the PDS221. This is exactly what I was hoping for. For me, it's crucial that the midrange cuts right through the mix.

The PDB512 sounded more relaxed too. No listening fatigue was encountered after an entire day of music.

Having lived with it for a few days, I highly recommend the PDB512 over the PDS221. It is perfectly usable with a 8.2uF in series. In fact, it's quite impressive, especially taking the price into consideration. Of course, it can be better when crossed with a super tweeter but that's for another day.


60 Downes Street | Calais | ME 04619 | USA