[ejfud]

Any experience with these drivers from anyone.

Cabinet ideas would be appreciated.

[Æ]

Any experience with these drivers from anyone.

Cabinet ideas would be appreciated.

You need the Thiele/Small parameters first.
I found this over at AudioKarma, just a simple bass reflex enclosure.

[ejfud]

From Hemps specification sheet

Frequency Range     60 to 20,000 Hz
Sensitivity               92.5 dB SPL at 2.83V1m (3.3 ft)
Rated power            25 watts
Program power        50 watts
Nominal Impedance 8 ohms
Resonant Frequency (fs)                             70 hz
DC Resistance (Re)                                    6.7
Mechanical Q (Qms)                                   2.717
Electromagnetic Q (Qes)                             0.54
Total Q (Qts)                                             0.44
Compliance Equivalent Volume (Vas)           10.89 liters
Diaphragm mass & air load (Mms)               2.39 gr
Linear Xmax(Xmax)                                    0.59 mm

Recommended for Hi-Fi and professional audio as a full-range, or a wideband mid-bass. Best suited for bass
reflex, transmission line, rear loaded horns and sealed enclosures.

[Æ]

I kind of like the idea of a Quarter Wave pipe, something slender and tall. You'd have to use Martin King's software to design one.

http://www.quarter-wave.com/

[planet10]

We put our HA FR4.5 into Brynn (BVR), would also work in Gabriel. I know of at least one set of Fonken sporting FR4.5 as well.

dave

[Æ]

We pot our HA FR4.5 into Brynn (BVR)

As in green thumb? Or was it was a parapraxis revealing repressed motives?

[planet10]

As in poor typing skills ... i took Grade 11 math instead of Grade 10 typing.

dave

[ejfud]

I was looking at the Brynn earlier today. Looks doable and nicely sized for my small room as well. Dave, any thoights on moving the driver off center on the baffle?

I think I'll try them in these first if they fit in the hole.




The Hemps have had a little treatment done to them. Not sure it's correct, but they should be fun to play with.

[planet10]

any thoights on moving the driver off center on the baffle?

I don't think that bang in the middle is the best place for the driver, officially they are offset vertically by the golden ratio.

I think I'll try them in these first if they fit in the hole.

IIRC a slight increase in hole and a detailing of the rebate ... long time since we worked with them.

The Hemps have had a little treatment done to them. Not sure it's correct, but they should be fun to play with.

Standard EnABL1 set... they are well done, looks like they could use gloss. And maybe a midcone ring-set.

dave

[TerryO]

~~~~~~~~~~~~~~~~~snip~~~~~~~~~~

Dave, any thoights on moving the driver off center on the baffle?

~~~~~~~~~~~~~~~snip~~~~~~~~~~~~

When I was designing the "High Tweek Blackbox Nearfield Monitors" a few years back, I was using edge for the baffle design. I kept coming up with a solution with the driver centered exactly in the middle! Knowing that a driver "has to be" off center I kept inputting the numbers over and over again (I know what they say about repetitious activity and expectations of a different outcome :^)

I went on for a couple of days like this, getting more and more frustrated until I finally called my buddy Dan Wiggins. I gave him my data and he proceeded to run them, until he told me that in some cases the driver "wants to be" in the exact center and all my results for the sims had been correct.

I believe that in most cases it's probably a good idea to mount the drivers off center...but evidently, as I found out, there are exceptions.

Best Regards,
TerryO

[ejfud]

Nice to know the dots were done correctly.

I obviously didn't look very close at the drawing Dave. I think I'll give the Brynn's a go.

Well Terry, way to cloud my already fuzzy brain.

[doucanoe]

Forgive my ignorance but with the EnABL1 treatment, does the material used to make the "dots" effect the sound or driver response or is it more about the pattern?

RC 

[ejfud]

I'll let Dave answer that one.

Here's a little reading for you RC.

http://www.positive-feedback.com/Issue21/standingwaves.htm

[chrisby]

FWIW, I quite liked them in Brynn - honestly can't remember what else I heard them in-  must have been 5(?) years ago

[Æ]

I'll let Dave answer that one.

Here's a little reading for you RC.

http://www.positive-feedback.com/Issue21/standingwaves.htm

While I believe there is significant merit to cone treatment, placing little dots along the edge of the enclosure is guaranteed to do practically nothing.

[JLM]

AE, I agree with your presumption about EnABLing the cabinet, but a few years back I had Bud Purvine (c0-developer of EnABL) treat my Fostex F200A and he provided a ring on the aluminum frame.   

The nice thing about having him do them is that I already had 5 years of use on them when he got them and by ear he discovered that another ring was needed for best performance as he'd never treated such an "experienced" pair of speakers.  (In his opinion, once treated the F200A may be the world's best driver.)

[doucanoe]

I'll let Dave answer that one.

Here's a little reading for you RC.

http://www.positive-feedback.com/Issue21/standingwaves.htm

Thanks, Gary.  I'm going to poke my head further into that article when I have a little more time to digest the contents. 

RC

[planet10]

Forgive my ignorance but with the EnABL1 treatment, does the material used to make the "dots" effect the sound or driver response or is it more about the pattern?

It is more about the pattern. The material used has to leave a bump (doesn't need to be big). On cones the material of choice is a high pigment flat arcylic paint (pollyscale train paint is the starting point). People playing with baffles & rooms will often use pieces of sticky tape.

The big discussions are on diyAudio. Besides offshoots, the big technical thread where speculation on how it can work, quickly shouted down by those who say it can't possibly work, and another thread where technics, patterns and impressions can be had. And those who mostly just sit back and enjoy what EnABL brings to their enjoyment of the music.

dave

[Æ]

AE, I agree with your presumption about EnABLing the cabinet, but a few years back I had Bud Purvine (c0-developer of EnABL) treat my Fostex F200A and he provided a ring on the aluminum frame.   

The nice thing about having him do them is that I already had 5 years of use on them when he got them and by ear he discovered that another ring was needed for best performance as he'd never treated such an "experienced" pair of speakers.  (In his opinion, once treated the F200A may be the world's best driver.)

That 'ring' is known as a diffraction ring, works in the vicinity of the driver, like blinders on a horse. Diffraction is always a problem and there are several ways to mitigate it. Front baffles ensconced in plush felt works good, but no one really likes the looks of it.

Diffraction artifacts can easily be measured, before and after. None of that BS that says one can only hear it because it's not measurable or some other nonsense like that.

Results of cone treatments can easily be measured too. Most manufacturers already treat their cones and surrounds to deal with problems that their engineers encounter. Take a look at some of the Scan Speak woofers, having factory split/sliced cones.

Ratch Higgins showed me microphone results, before and after of an inexpensive paper cone wide range driver treated with varnish. About ten years ago or so, 'Damar' was all the rage, everyone was advocating the treatment of paper cones with it. It did work too, softened the sharp edges on the frequency response at the expense of some efficiency.

[planet10]

Results of cone treatments can easily be measured too.

Easily is not a word i would use. In the case of measuring many things (electronics, speakers, rooms), including what EnABL does, requires the ability to detail what is happening on the order of 40 dB down in the presence of the 0 dB signal. When talking about measuring a speaker, this means a very quiet environment.

One of the problems we have in the amateur speaker builders is that the plethora of crude measurement tech that has become readily available is not recognized as such, and that once given the tool all problems are treated as if that tool will deal with it (ie if your tool is a hammer, then everything looks like a nail)

dave