Exploring Purifi Woofer Speaker Builds

This driver makes a nice midrange but it was designed to be able to move a lot of air in a vented alignment. It would be a waste to use it on an OB. You couild use so many other drivers there as a midrange. Try Faital 6FE100 or 5MR450NDY. They have higher Qts and are also low distortion, and higher sensitivity.

A waste due to the relatively high cost for the performance, or because it would operate suboptimally?

The benefit of Purifi could be that a very low crossover could be used in OB, e.g. 100-200 Hz, maybe with a pair. And still it could go up to 2k or 3k, with very low IMD and THD.

I looked up the drivers you suggested, but they look not particularly special (though your response is appreciated!). As James, I am looking for a very high performing mid: very fast (to integrate with Heil AMT), wide bandwidth (to be flexible with crossovers and have low crossover to 15" woofer), very low IMD and THD. And useable in open baffle, so high xmax, higher Qts nice to have.

My short list so far is Purifi, Satori MW16 or MR16, and maybe some 8" wide banders. I already have a Supravox 215 Bicone which I will try out, but I expect its distortion and breakup will be much worse than Purifi...

Fedde
 

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Well, if you have EQ available you can choose any Qts bass unit. The high(er) Q need for OB is when one want decent output in the bass without EQ. But using a driver with a Q>0,5 is really to rely on resonance and that I would avoid really. This high Q bass driver in OB is a grand-paa problem - nowadays we do Q 0,5 with low reach using LT transform in DSP... good luck! (But 6" wont cut it in the bass of course!)

//

Thanks for the suggestions and I agree that the Purifi's Qts of 0.32 is not optimal for OB.



I find it difficult to get hold of CSD and HD info on drivers so that eliminates the vast majority of drivers, unfortunately, but without being able to hear drivers beforehand this is all I have to go on.



I did find some distortion plots for the Faital but it doesn't seem to be in the same class as the Purifi with H2 and H3 HD hovering around -30 to -40dB. (Purifi is -60 to -70 dB).



Both drivers you suggested seem to have a linear Xmax of around 3mm compared with the Purifi's 10mm. The extra Xmax should give me some extra crossover flexibility, so that's another plus for the Purifi.



I'm also not concerned with high sensitivity as I will have 250W available for the midrange from the Hypex FA253.
 
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A waste due to the relatively high cost for the performance, or because it would operate suboptimally

It will sound great - I was speaking from standpoint of cost effectiveness. In OB, you could probably take it down to 200Hz, but the sensitivity due to OB falloff is probably at least 6dB so it’s going to need EQ and it’s long stroke to compensate. Give it a try if the cost doesn’t bother you. Satori might work too but then you have the breakup on top to deal with.

I have tried the 5MR450NDY in OB and it sounds special. It is very low distortion as the sensitivity is so high, it doesn’t move very much. I crossed at 340Hz and had a slot loaded OB (SLOB) w 6x 6.5in woofers for the bass.

Cheap and FAST OB, Literally

429053d1405682518-cheap-fast-ob-literally-slob-response-5mr450-ndy-fast-1m-meas-png


This response was achieved with no EQ or BSC, just the crossover filter and level matching. Lucky indeed. It sounded very very good - I made a note to myself that one day when I have access to a wood shop I would recreate it in plywood as it was only made of cardboard.

429052d1405682518-cheap-fast-ob-literally-5mr450ndy-fast-furious-photo-1-png
 
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It will sound great - I was speaking from standpoint of cost effectiveness. In OB, you could probably take it down to 200Hz, but the sensitivity due to OB falloff is probably at least 6dB so it’s going to need EQ and it’s long stroke to compensate. Give it a try if the cost doesn’t bother you. Satori might work too but then you have the breakup on top to deal with.

I have tried the 5MR450NDY in OB and it sounds special. It is very low distortion as the sensitivity is so high, it doesn’t move very much. I crossed at 340Hz and had a slot loaded OB (SLOB) w 6x 6.5in woofers for the bass.

Cheap and FAST OB, Literally

429053d1405682518-cheap-fast-ob-literally-slob-response-5mr450-ndy-fast-1m-meas-png

Indeed, the response looks very good for a two way without EQ!

I look forward to the 8" Purifi. This would probably be a more cost effective option for open baffle as two units could be enough for deep bass. And efficiency will probably be higher. But it let's first see when this becomes available and what the price is...

Fedde
 
Indeed, the response looks very good for a two way without EQ!

I look forward to the 8" Purifi. This would probably be a more cost effective option for open baffle as two units could be enough for deep bass. And efficiency will probably be higher. But it let's first see when this becomes available and what the price is...

Fedde

Hell after success of the 6.5 I look forward to any drive they bring out " ill take 4 10s and a couple of 4, don't bother wrapping them" 😁😁
 
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I am more impressed by the clear and clean midrange that the 6.5 makes. It is world class midrange like a nice fabric dome but with chest punch.

Absolutely 100% agree. A good $400 15" woofer in a 5 cubic foot box or a 5 foot tall line array of GR Research servo woofers will deliver bass comparable to PURIFI's. It's the mid range clarity obtained by going after the previously unrecognized hysteresis distortion that is the currently unique benefit I hear from PTT6.5.