Redcatt 81Find


I received the sample from Redcatt South Africa, as always Oliver big thanks for giving us another driver to test and review.

Having us test various speakers helps me inform you best, last thing you want to do is buy a speaker and hope for the best but we have some trust to best represent the product openly and fairly. Which in my opinion builds brand trust between myself and dealers throughout the country but also the people like yourself who might be in the market for a good 8"/


We follow the normal steps, calibrating the test lead & impedance calibration on DatsV3

We proceed to test our driver entering the diameter and the added mass method for testing for Vas and out pops our basic parameters.


Right look cool, time to pull this information into Winisd ;) 



Lets create 3 types of vented enclosures ( winisd ) pre defined alignments

  1. Qb3
  2. Boom Box
  3. Chebyshev


We can see quickly using these 3 alignments we should not be expecting much bass here at all, which we should of had realized by looking at the drivers Fs and the low numbers on the Xmax side of things.

A second thing to note is the speakers Re value being well below the norms representing more of a 6 ohm speaker and not that of an 8 ohm typically found in the market when talking Pa speakers, inductance is also "kind of low - ish ) which give me a good impression that we should have relatively good high frequency extension on axis maybe out to 4 or 5khz. Everything is pointing to this speaker so far best being used as a midrange driver but lets inspect further. 


First thing I'm going to do to end my suspicion of the Redcatt 81Find being more midrange application is to put some power into the speaker in simulation, should we run out of Xmax at very low levels it will indicate more for midrange use though if we see our input Watts is close to the rated power of the driver it might be a good woofer and we can creep out some lows.


Qb3 4 watts

 


Boombox 4 watts give or take here also


The Chebyshev confirms with hardly any power we are again right into Xmax on the tail end of this driver, 4 watts might not be much though the drivers still loud at these levels thanks to the sensitivity being high. 



Now that I can see this speaker is more a mid looking at something simple as Power in vs Xmax against our actual power handling capacity, in order to reach our power capacity we need to mechanically limit the driver by taking away bass by using a high pass filter so lets do that!


Now wait just a second.. I mentioned we could maybe use these for line arrays on Facebook right?

Hmm this could be interesting if it is a midrange we will then need a woofer and if we wanted to use this as a woofer we might run into some issues very quickly!

Which means if this is being used as a midrange to exploit its power handling potential we would most likely best use this speaker best in a 3 way design, which is more complicated for the novice, though dont shy away from trying to build a multi way speaker system as it can reward you when done right.

  • Define just how much of the thermal value you need or want, do I want to use the full 200 watts you might need to crossover very high up
  • Define that frequency, generally and broadly speaking this could be from 200 to 400hz all the way up to our high frequency speaker.
  • Understand that everything that fits inside that speaker in the higher frequency spectrum will beam which is bad so lets get an idea by using the size of the speaker in mm and working out the wavelength.
  • 172mm is our number and this gives us a frequency of 1994Hz, ideally we want to crossover below this range but not always possible or practical.


Using our Qb3 enclosure we reach around 70 watts with our 1st order high pass filter set to 200hz.


Jumping to 400hz we might be missing out on some of the low midrange / mid bass but if we care about that extra dB or 2 vs our 70 watts to Xmax then lets see 400hz which should nail it even on a 1st order



I would relax the crossover point for sure, generally speaking the lower we crossover the better when looking at speakers technically but passive parts can become expensive fast so it really boils down to application and requirements.

You could even use this as a little woofer or 2 way Hi-fi speaker just remember its far from the performance of a true mid bass / woofer in specifications.


We should repeat this process of evaluation with each of our general cabs, see how the Xmax will change with each design and layout. As far as line array enclosures 400hz to have directivity control of any sorts we will need an array closer to 1.75 to 2.5 meters in length to have any control but that's for you to decide!


Part 4 I will share my design and we will be cutting and building our enclosure, validating our design against actual Zma & Frd Measurements.