PRV 5MR450-NDY for FAST/WAW applications

[xrk971]

PRV, a Brazillian Pro Audio driver company makes nice PA drivers, and I recently found out about an interesting offering from their "Woofer" line. The 5MR450-NDY is woofer that may interest some of you as a possible high sensitivity wideband unit. It is labeled a woofer but the spec sheet clearly shows promise as a fullrange driver with highs extending into the 15kHz range. There are two variants: 8-ohm, 0.57 Qts at 95dB and 4ohm, 0.42 Qts at 98dB sensitivity at 2.83 volts-1-meter. Certainly this is not the first 95-98dB wideband driver, but I don't know of another rated for 250 watts RMS with 2 mm of xmax - if you do the math, the max SPL from this driver is pretty high up there and earns this driver, the moniker of "El Rey" for FAST. There is a limitation of course, it cannot produce bass below 200 Hz and as such, needs a helper woofer or sub, hence I qualify it as a driver for a FAST (fullrange assisted subwoofer technology, i.e., 2-way with a low XO) configuration because the fs is about 170Hz to 180Hz. But, this frequency range is about an ideal XO point for a FAST system. If you have an interest in having a fullrange top driver that can light up a room keep reading.

8-ohm variant:
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4-ohm variant:
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I received the 8-ohm variant drivers the other day (about $105 ea - yeah, I know, I can buy 10 Vifa TC9FD's for one of these... btw, the front view looks just like an oversized TC9FD, down to the front foam gasket and rounded off square frame 🙂 ) and they look solidly built with a nice cast aluminum frame, solid thick paper cone, and a bevy of radially mounted Nd magnet slugs, and a vented pole piece for good cooling. The suspension and cone are very STIFF to achieve the high fs and high efficiency - I could barely get it to flex with finger pressure. There is no whizzer cone, just a stiff hemispherical domed dustcap - which I believe is why this thing works so well at HF's - it acts like a dome tweeter.

I proceeded to mount it to my cardboard test OB "Cheap and FAST, Literally" setup after making a new foam core adapter plate. Here is a photo of the setup. The driver is offset so that the center is 5 inches from the side and 5.5 inches from the top in a 12 in wide open baffle with small wings on the back. I hooked it up with the mic on axis at 1 meter away and took this measurement:

Here is the factory frequency response data:

I was really shocked by how good this measurement looks, and I think that you will agree that may even be smoother than many a more expensive 95dB class full range drivers out there with names starting with an L or F. None of them will match it in SPL capability. Many folks will be perfectly happy with 15kHz highs, and a helper super-tweeter can always be added for more "air". The bass starts falling off at 340 Hz here, and that is consistent with a 12 in wide baffle with a one inch offset mount.

For a simple yet high SPL capability, high passing at about 230 Hz (in a 6 liter sealed box) lets you put into it a solid 200 watts RMS for 113dB SPL (xmax limited), and still stay below the 250 watt thermal rating. If you front-horn loaded it, you can get some amazing SPL's in the 120+ dB range. Here is the prediction of the SPL in a 6 liter sealed box (Q=0.707) with 35 volts rms of drive:

I did not have time to set it up in a FAST with a woofer yet, but did manage to listen to some test tracks where I knew what the sound should be like above 300 Hz. It sounds very nice and articulate, smooth, and an amazing level of detail and sparkle from heavy paper coned PA woofer. Snare drums, high hats, clicks, drum rim shots, all were present and sounded good.

If you want extension down to 100 Hz to pair with a traditional non-directional "sub-woofer", alignments like a bass reflex, MLTL, even BLH can be employed and they have the advantage of being rather small as only 100 Hz bass extension is needed.

I will add more predictions in other alignments and if anyone else has some experience with this driver, please let me know how you like it.

Edit: this driver can be used in a 300Hz to 15kHz tractrix horn too. Here is the response and harmonic distortion (which is very low).

Here is the horn:

Edit July 24, 2021: Recent detailed measurements in Hypercube here:
PRV 5MR450-NDY for FAST/WAW applications

 

[xrk971]

In case you don't know what this driver looks like - has magnets like a W5-1880, which, by the way, was 88dB efficient and was rated for 30 watts as opposed to 250 watts.

An externally hosted image should be here but it was not working when we last tested it.

 

[planet10]

8-ohm, 0.57 Qts at 95dB and 4ohm, 0.42 Qts at 98dB efficiency at 2.83 volts-1-meter.

Let's note that if the input is 2.83 V you aremeasuring sensitivity not efficiency.

dave

 

[xrk971]

Thanks for catching that - updated post 1.

 

[Cal Weldon]

Looks pretty interesting. Thanks for posting X.

 

[xrk971]

Looks pretty interesting. Thanks for posting X.

I wonder if this driver, appropriately loaded with a high compression ratio back horn like the Cornu will generate some bass down to 100 Hz?

 

[Cal Weldon]

I'm thinking that's wishing for something that's just not gonna happen. 🙂 The latest 36" version, I would love for you to hear but that's a different driver and it's for another thread. I think this driver with a big ol' PA woofer might be the cat's meow for some of those nights when you need a little kick and all you have is one of those toy amps.

 

[xrk971]

Yes, you are probably right Cal. Something like a 15 in 98dB woofer would be nice. This driver is interesting because I feel like it is designed to operate in a pistonic mode rather than having the cone flex and breakup. The paper is super thick and stiff. Stiff may be good for coupling to a BLH.

 

[freddi]

cute driver - pricey but nice - can it work to any advantage with a shallow K-coupler lens and sealed/aperiodic rear chamber? how is it on top somewhat off axis?

 

[xrk971]

I plan on taking polar measurements soon to see how well this works off axis. Yes, I have also wondered how this can work in a small K.

 

[xrk971]

Polar & HD measurements

I took some measurements of this driver at 1 meter away in the OB shown on post 1 at the following angular positions: 0, 15, 30, 45, 60, 75, 90 degrees:

Here is the distortion at various harmonics at about 92dB SPL:

Here is the nearfield (0.4 m) showing the phase linearity of the point source:

Here is the nearfield (0.4 m) showing harmonic distortion at 89 dB SPL:

 

[xrk971]

Measurement in Slot Loaded OB FAST & Sound Clips

Measurement of this driver in the slot loaded OB (SLOB) http://www.diyaudio.com/forums/full-range/249984-cheap-fast-ob-literally-39.html#post3995444 using the Breeze Audio 2.1 class D TPA3116D2 amp with built in XO for sub and tops run fullrange (http://www.aliexpress.com/item/TPA3116-50W-50W-100W-2-1-HIFI-digital-power-amplifier-D2-SN/1719548803.html?albmt=broad&gclid=CjwKEAjwi6OeBRCCrZqp-qaQhhISJACrfbtAkQQH95L30GBWL_2WTofgZbcmpLuCBHlHUsrA0Xbr7BoCZpXw_wcB&creative=31447451305&albag=home_none_Search-ALL-PLA_1013999999870&albom=OTHERS_None_20130807_Aliexpress&albcp=Search_Search-ALL-PLA&isdl=y&ptsid=1013999999870&albst=search-text&albch=Google&src=Google&af=ppc&albkw=None_US-Shopping-Search-Product-AliExpress_none_none). The perfect integration of the falloff at 340 Hz and the woofer channel was pure luck as the XO frequency on the amp is not adjustable - just relative gains. Anyhow, it measures pretty well given that this is raw with no DSP, no EQ. Straight from source to amp.

If you are interested in hearing what this driver sounds like, and want to hear the highs that it can resolve here are some sound clips (in mono):

diyAudio

diyAudio

diyAudio

 

[anthonybisset]

This looks like a modern, flatter, better performing version of the JBL LE5-2 (now sought after). The LE5-2 was a favorite of Bruce Edgars for use in 400hz tractrix horns. Looking at XRK's measurements I'd be inclined to try it in most any alignment (with a woofer or sub). The recorded clips sound accurate to. The tonal balance in the second is frustratingly good...

I've been watching keeping an eye on full range offerings for years, this is the first that actually gets me excited.

 

[xrk971]

This looks like a modern, flatter, better performing version of the JBL LE5-2 (now sought after). The LE5-2 was a favorite of Bruce Edgars for use in 400hz tractrix horns. Looking at XRK's measurements I'd be inclined to try it in most any alignment (with a woofer or sub). The recorded clips sound accurate to. The tonal balance in the second is frustratingly good...

I've been watching keeping an eye on full range offerings for years, this is the first that actually gets me excited.

Good call on similarity with LE5, some data here from the web and 5MR450 does appear smoother with higher reach on top. It will be really interesting to see how the 5MR450-NDY looks in a good tractrix FLH.

 

[xrk971]

The JBL L26 that used the L5-2 driver, a 3-way with a 10in woofer was restored by Troels G ( JBL L26 restoration, ) and had a very complex XO all to get this response:

I think the response I got with the 5MR450 in a simple bi amped SLOB looks much better as a two way.

 

[FullRangeMan]

PRV people are former engineers from Selenium which was taken by JBL/Harman giant.

 

[xrk971]

PRV people are former engineers from Selenium which was taken by JBL/Harman giant.

Selenium is good stuff, gives the PRV product line a little more heritage. It's interesting that more high sensitivity-high power fullrange point source drivers are not designed/used.

 

[FullRangeMan]

Selenium is good stuff, gives the PRV product line a little more heritage. It's interesting that more high sensitivity-high power fullrange point source drivers are not designed/used.

According my esperience since the 1970s, hi power fullrange drivers are as hi power amps, the sound are bad, hard, agresive mainly the mid/treble.
The harmonics seems are few too.

 

[xrk971]

According my esperience since the 1970s, hi power fullrange drivers are as hi power amps, the sound are bad, hard, agresive mainly the mid/treble.
The harmonics seems are few too.

This one actually sounds pretty good. Kind of like a 95dB sensitive TC9FD in smoothness. Not harsh at all and the measurements show that. I have been listening to it all day and with quite a wide variety of music and it still sounds great. No hint of fatigue whatsoever. The distortion is also extremely low as you can see at 92dB its in the -50dB levels. The cone doesn't move much and this probably contributes to the low HD.

 

[anthonybisset]

Again, XRK's sound clips sounded really good to me. My first thought was how close the FR and smoothness of upper midrange into treble matched what I've heard from Funktion 1 Resolution 1.5 monitors. The 5MR450-NDY looks like an accurate very low fatigue speaker with great specs. Thinking I'll order a pair to play with this week!