PRV 5MR450-NDY for FAST/WAW applications

[perceval]

I searched for this but was unable to find the thread

Really?

As up this moment, it's the third thread above this one.
And after I post, it should be the fifth one under this.

 

[Jeffry Ames]

Really?

As up this moment, it's the third thread above this one.
And after I post, it should be the fifth one under this.

I don’t know Myself around the diyaudio.com pages very well, there’s a Tapatalk too that I get notifications for but haven’t spent much time there either...
I’ll find it, just need the right words in the search thingy 😜

 

[xrk971]

Here you go:

10F/8424 & RS225-8 FAST / WAW Ref Monitor

 

[Jeffry Ames]

Thank You!
Very interesting!
Hmmmm....
I can see some testing in My near future!

 

[Defo]

Are there any FRD and ZMA files out there for this driver?

 

[multi]

Horn flares

Are there any designs for mid-range horns? For the PRV 5MR450- ?
I bought a 6.5 inch horn from China, but have not found a suitable driver so far.
I have an 8 inch speaker with the following specs; I bought a horn flare to suit, but seems small; I need to crossover at 250 to 300HZ .
3 INCH COPPER VOICE COIL

97.3 dB/SPL SENSITIVITY

800 WATT PROGRAM POWER HANDING

FEM OPTIMIZED MOTOR AND SUSPENSIONS

OPTIMIZED COOLING SYSTEM

DOUBLE SPIDER

RESONANCE FREE AND HEAVY DUTY BASKET DESIGN

IDEAL FOR TWO-WAYS AND LINE ARRAY APPLICATION

GENERAL SPECIFICATIONS
Nominal diameter
mm (in.)
213(8)
Nominal impedance
Ω
8
Minimum impedance
Ω
7.2
Program power (1)
W
800
AES Power rating(2)
W
400
Sensitivity (3)
dB
97.3
Frequency range
Hz
64 ~ 3500
Voice coil diameter
mm (in.)
75(3)
Chassis material
Aluminium

Magnet material
Neodymium

Magnet dimensions (ODxIDxh)
mm
74 x 15 x 10
Coil material
ALR

Former material
Glass Fiber

Xmax(4)
mm
5.5
Xmech(5)
mm
11
Gap height
mm
10 x 2
Voice coil Wingding height
mm
36

SMALL SIGNAL PARAMETERS
DC resistance
Re
Ohm
5.8
Resonance frequency
Fs
Hz
63.7
Moving mass
Mms
g
31
Compliance
Cms
mm/N
0.20
Force factor
BL
N/A
21.9
Mechanical Q-factor
Qms

5.0
Electrical Q-factor
Qes

0.18
Total Q-factor
Qts

0.17
Equivalent air volume
Vas
I
16
Voice coil Inductance
Le
mH
2.2
Diaphragm area
Sd
cm²
240
Reference efficiency
Eta 0
%
2.6

 

[xrk971]

In this thread post 96:
https://www.diyaudio.com/forums/ful...ndy-fast-waw-applications-10.html#post4033969

Go to Volvotreter’s website - there is a spreadsheet for tractrix horn design.

Tools – Volvotreter Homepage

 

[multi]

xrk971
Thanks very much!
I will check the website.
I do have a Dr Edgar tractrix horn, made many years ago
Phil

 

[xrk971]

Just use the Edgar - it should work very well for this driver.

 

[sumotan]

Hi xrk971,

Hope you don't mind giving me a tutorial. Re Edgar horns, the throat opening is around 2 x 2 inch, in using a 5 inch FR like PRV, does the un exposed cone area behind the throat of the horn not cause reflection affecting sound & would bevelling or rounding of the inner side of the throat help smooth up sound from throat to neck of the horn.

Thank you kindly

 

[xrk971]

The throat on my 5MR450NDY was bigger than 2x2in. I can't remember off the top of my head but I think I chose it based on the throat diagonal being the same size as the membrane diameter. Ideally, you want a 3d printed throat that smoothly goes from the entire driver past the surrounds and have to gradually converge to the square shape of the horn throat. I did have a few reflection dips. This was something we worked really hard to avoid in the bookshelf point source horn.

A Bookshelf Multi-Way Point-Source Horn

So I ended up making an adapter like this round to round though):

It went on a commercial waveguide like this:

Even with all that, I still had a small dip at 12kHz:

 

[sumotan]

Thank kindly for the advice. When reading Bruce Edgars article I always wondered about reflections etc as he was using JBL LE5 on a 2x2 inch throat.

Many thanks again

 

[Defo]

How does the 4 ohm version compare to the 8 ohm version? Is there a preferred version?

 

[xrk971]

I like the 8ohm better just because it lets me use a wider variety of amps. Many of my Class A amps are 8ohm only.

 

[freddi]

Here's Bruce's 250Hz horn w. LE5 vs a conical horn with Alpha 6A (neither with backhamber) outdoors - IIRC the tractrix horn's throat was square and 2.5"x2.5"

 

[capslock]

Just got a used but pristine looking pair of 5mr450-8 but haven't played or measured them yet.

One thing I noticed: when I tap the cone about half way between dustcap and surround just lightly with the flat of my finger, I get an almost musical, conga like tone. I don't think I have ever experienced this with any driver, let alone a pro midrange. Isn't this indicative of an undamped resonance? The FR graphs in the data sheet and published here (sorry, haven't waded through all 60 pages) look too flat for that.

Has anyone had a similar experience?

 

[freddi]

that may be from the very high Qms which indicates less loss in the suspension than a lower Qms number allowing it to "ring". In action, Qes should dominate. I wish they had a less expensive (ferrite) version.

take a jumper and short the terminals - does it sound different ?

 

[capslock]

Hadn't thought of that. Yes, it sounds different, shorting takes away lots of the mids I hear. Now sounds like mini congas.

The motor probably can't dampen cone modes that happen further out.

 

[xrk971]

I recall noting that the suspension on the 5MR450 was about the stiffest thing I have ever felt on a midrange driver. The membrane barely moves when you push on it with your finger. Perhaps the stiff suspension, coupled with a stiff diaphragm makes for a good conga drum? But the measurements and sound don't really show a conga drum resonance.

 

[freddi]

hi X Have you ever thought of putting 5MR450 in a little K ? Would that be as listenable as direct radiator ?