a jordan JXRHD speaker : need your advices

[motutunga]

hi,
I try to know the kind of sound I can get with those bright JordanJXR6HD speakers: I want to use them as main speakers outside of my sailing boat.
I desing the box in a WC exaust hose ( have to resist storm force wheather= see attached). It is a regular bass reflex 2.8l box / 3.6cm diam and 17.7cm long vent.
It seems to go a low as 85-90hz as shown by WinISD curve, but I found first the sound a bit "shrap" and in fact it appears on the typical response curve that it needs a slight attenuation (4-5 db) after about 300 hz. So I add:
an attenuation circuit
a 6db/oct- 10000 hz lowpass filter
an impedance correction circuit
All that could seem to be a lot for such small speaker but the fact is that I enjoy the result.Very precise , bright and not aggressive.

But I need your advises or experience about such filter for this fullrange
See fdoc attached an excuse my bad english

 

[Colin]

I'm using the JXR6 in a similar size enclosure but it is a more conventional shape. I wouldn't have described the sound as sharp but bass-light. Used against a wall balances it out better but bear in mind that it is not really designed to be used on its own. It's a mid-hf drive unit.

Even in an array of four, it is only suitable for use down to 150Hz or so and needs a proper bass unit of some sort below that.

 

[audiosteve]

I have a pair of jxR6HDs that I use for portable speakers and I think they sound great. Not sharp at all. But aside from that, the JXR6 has no spider and the mfg insists on its use in a sealed enclosure to provide proper cone support. I'm not sure using it in anything else is a good idea.

 

[motutunga]

I have a proper bass unit with it: it is a passband 6th order cut off about 130 hz: design with two 13cm focal5 5ve3251 push pull feed by a second car amplifier ( remember it is for a boat). So for the bass it's ok.

If anyone has another point of view ?
Actualy I do not find it is bass light according to its possibilities ( down to 100 hz max), it is really the medium range i find to "loud", do you thing it is because of the bass reflex , , should I rather use a closed enclosure?
In this bass reflex the bass are really great for such a tiny speaker, and even with " hard sound" like Marcus miller for ex it holds about 10w power. that seems incredible to me as WInISD give a 88Hz response, and seems to be the truth ( I am not equiped to mesure it)

 

[Colin]

I hadn't realise you were using it in a bass reflex. So yes, it is very likely that - you're using it in a way which was specifically NOT recommended by the manufacturer.

As Audiosteve says, the JXR6 has ferrofluid suspension and no rear spider. It relies on the sealed box to provide the rear suspension and damping. Quite apart from the sound implications, you run a risk of damaging the drive unit. And don't forget these are now hard to get hold of so if one goes, you're looking for a pair of other-make drivers.

In my experience, whatever the computer simulations say, the JXR6 rolls off below 150Hz in whatever size box you use it (I've tried up to 4 L).

 

[motutunga]

thanks a lot for all that.
So i'll have to try a closed enclosure ( about 2 l I think) and modify the bass unit for a upper cutoff at 150hz
I think that's be great and i'll hope to enjoy the music in the south oceans ( antartica and south georgia ) where I plan to sail in a year or two

 

[Colin]

Nice to see an unusual listening room for DIY speakers!

Let us know how you get on. The trip sounds fantastic.

 

[motutunga]

i modified the speakers closed enclosure( I just shortened the hoses) 2.2l, semmes to sound great, they are now "more" water prof than before.
For teh bass unit I shortened the vent for proper resonance frequencies

 

[chrisb]

You might also want to reconsider the depth to which the drivers appear to be recessed in the PVC elbow - these have fairly wide dispersion and I'm sure would be effected by the cavity formed by the close perpendicular side walls

And keep Colin's notes in mind - without substantial efficiency cutting EQ, don't expect much in the way of LF extension or SPL from any configuration of singles, or even doubles of this driver per side.

 

[motutunga]

I put a olt of damping material inside, sound rather good.
Sorry but my english is poor; what do you mean with"substantial efficiency cutting EQ".
In fact I simulate with an equalizer the result of the resonant circuit RLC shown at the begining, and if you mean there could have "bad" resonances this simulation gives THE good result...
unfortunatly I discover this kind of forum just some weeks ago and it is the first time for 20 years I made a new speaker..
20-30 years ago I used to do all by the ears like an "artist" with fair results, because pro equipment was very expensive.. I designed about 25 pairs of speakers at that time... I still have the last ones with now brand new drivers; but I am not really used to new mesurement tools, and nearly not to english technical words.
And no I do not believe everything I say as you profile asks; you are there to tell me the truth
Philippe

 

[motutunga]

why Am i here ; I do not go on french forums because i find the frenchies pretentious and withering sometimes

 

[chrisb]

I put a olt of damping material inside, sound rather good.
Sorry but my english is poor; what do you mean with"substantial efficiency cutting EQ".

Perhaps that phrase was poorly worded - my point was that often builders will attempt to compensate for trailing LF response by aggressive EQ. Whether performed actively before amplification, or passively, and whether by boosting lower frequencies or reducing higher ranges, the results will effectively be the same - potentially smoothing the measurable and audible response adequately, but there's no magic solution to any given driver's X-Max / excursion limits - which will ultimately determine the volume levels attainable. With drivers possessing enough sensitivity and excursion capacity, this is not necessarily an issue, but the little Jordan might not meet those criteria.

In fact I simulate with an equalizer the result of the resonant circuit RLC shown at the begining, and if you mean there could have "bad" resonances this simulation gives THE good result...
unfortunatly I discover this kind of forum just some weeks ago and it is the first time for 20 years I made a new speaker..
20-30 years ago I used to do all by the ears like an "artist" with fair results, because pro equipment was very expensive.. I designed about 25 pairs of speakers at that time... I still have the last ones with now brand new drivers; but I am not really used to new mesurement tools, and nearly not to english technical words.
And no I do not believe everything I say as you profile asks; you are there to tell me the truth
Philippe

again, perhaps the sarcasm of that signature line doesn't translate well - I certainly don't believe everything I think or say, and definitely shouldn't be relied upon for "truth", other than as I see it - which can vary over time.

 

[motutunga]

hi,
I am was right to come for advices here..
anyway this Jordan is the best driver I found for the way I want to use it, because the speakers must be small and good and water proof and simple etc....

again this morning ( in france ) I listen to the final system and it is really an "enormous sound" regarding to to size of the driver. ( 2.2 l closed + passive equalisation + bass pass band cabinet 50 to 150hz).
I test it last night with metallica black album and it was the first time I heard the mediator on the bass string !!!!! incredible sound up to 10w or so

next time with some more money I'll try to make an array for home
hear you all soon

Philippe

 

[zman01]

Philippe,

Enjoy the music - Wherever you may roam!