New Manufacturer: Hemp Acoustics.

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I wouldn't "buy into" the cone material too much over say something as exotic as fostex's bananna pulp.

Remember that with "standard" diaphrams its a combination of properties:
1. Propagation Speed
2. Elasticity/Rigidity modulus
3. Internal loss (dampening)

(its numbers 1 and 3 that essentially define the audible "character" of the diaphram material.)

Just looking at their promo. lit. suggest that their hemp pulp has a higher propagation speed than fostex's bananna pulp (higher tensile strength), but chances are that internal loss will be less than the bananna pulp.

So really its a "give and take" thing.

Frankly they need a L O T more info. on their site ( price, T/S param.s, freq. plots (on and off-axis), CSD plots, etc.)

Still its nice to see another manufacturer.
Agreed that they need to work on the detail contents of their site. A West-Coast friend (who shall remain nameless at this stage, unless he wishes to identify himself?!?) told me about these things quite some time ago, having had advance knowledge and samples etc., but we've had to keep it under wraps for reasons i don't have time to go into here. We've been working on several enclosure designs -TL and ML TQWT for the 8" drivers and I'm going to start on the 4 1/2" when I get a spare moment (not as often as I'd like currently.) Hemp cones have been well-known to bass-guitar players for some time for its mechanical and subjective properties: it has superior damping to most conventional paper-pulp cones, and also far superior tonal colouring in this application, hense their enthusiasm. Besides, its broad-minded thinking, and this is always good, so long as its based on sound sceintific practice rather than voodoo.
Very Long!!

I've been a pair of these drivers for a couple of weeks and thought it would be wise to add some comments. When talk of these started several months ago, I correctly guessed who the OEM was and contacted them. I agreed to give the prototypes a listen during the development of the drivers. As of yet, the manufacturer does not plan to market these themself, and it appears that Hemp Acoustics will be the primary/initial distributor. To that end, the OEM asked me to avoid using their name. These are the same drivers used in Omega Loudspeakers HempTones. The OEM also builds the Tone Tubbies. They are all manufactured in the USA.

Despite how the marketers make it appear, the drivers are still very much under development. The specs I have seen posted on other forums are not from the most recent version. All of my knowledge only relates to the ferrite version. The actual specs look a little strange, but work very well.

The pair I have sounds fantastic. I am listening to them in cobbled together 2 cu. ft. sealed boxes. I have ports in them tuned to about 30 hz, but I think I prefer them plugged. They are incredibly fast, dynamic and detailed. The midrange sounds great and the bass is very musical. They are bright. Some of the initial people consulted by the manufacturer asked for them to have a considerable amount of highs, and the manufacturer nailed the request. I prefer them with a small strip of weather strip damping the whizzer right behind the roll, and a hard foam practice golf ball suspended right in front. I have tried a few other things, but this is my preferred combo.

I don't have any Fostex's on hand to compare to. I would advise browsing the Omega Loudspeakers forum if you are interested in this. Omega does some proprietary mods to driver to tone the highs down. In that form Omega seems to prefer them to the Fostex drivers.

The manufacturer wants them perfect before they are released. During the wait, it seems marketers have gotten antsy to get some info out and it has been premature. I think anyone who has heard these would share his or her enthusiasm though. I heard this morning that another prototype version would be done next week. It should be toned down a bit in the highs. I'll report back when I hear it.


p.s. I have no connection to the manufacturer other than a pair of hemp drivers in my living room that I have not yet paid for.
This thread seems well dead, but I said I'd update.

I received the new versions early this week. They sound much different, and in most ways much better. They are considerably smoother and easier on the ears. I haven't seen SPL charts, but these sound much flatter. I started listening to these with the golf balls, and soon removed them. They are unmodified. Dynamics, imaging, scale and speed are unchanged. I could tell that the midrange was lovely on the old versions, but it was overshadowed by the treble. Now the midrange can be heard for what it is, warm and clean. The new versions don't sound quite as exciting, but I think that quality was partially due to excessive treble. The old versions could get fatiguing; these are not.

The specs of the new version are a little different. The old version required either a very large vented box, or a smaller sealed box. These can't produce much bass in a sealed box, but the optimum vented box is less than half as large. I have them in the same 1.8 cu ft box, vented and tuned to 42hz. This is not nearly ideal, but it works. The bass is a little wooly, but they are probably much to close to the back wall.

I think SPL charts will be available on Hemp Acoustics website within a couple of weeks.

Hope this helps,

I visited the factory a couple of days ago, and took my speakers down for them to hear. I was able to see several versions they are testing. The higher end versions are in development. I saw several prototypes with different whizzers, phase plugs, and other variations. They have some different surrounds in to try on all of the 8” versions. 4.5” drivers are on their way too. I should have a pair of those in a couple of weeks. A 6.5” version may be in the works, but it is farther off. I was very impressed with the facility. After seeing how many things they are working on I understand why this is taking some time.
The main difference between the 8” versions I have is that the first has a copper shorting ring, and the later doesn’t. This is the main difference between the Fostex 206 and 207 as well. I prefer the driver without, and only one person who has heard both prefers the driver with the shorting ring. I saw frequency response charts, and each version is very similar to the respective Fostex driver. The hemps are a little smoother overall.
I can assure you, now having seen the place, that much R&D is going on. I think the regular 8” drivers are fairly close to market. The manufacturer confirmed that they have talked to Solen and also Madisound about distribution, as well as Hemp Acoustics. I’ll keep you updated if I get new news.

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