Jordan JX92S on wall for HT

[J-P B]

Hi,

I'm building a HT-system with the speakers wall-mounted. After good sound (as it would be used for music aswell) the next most important factor would be size, so smaller is better, otherwise I would propably go with the MLTL's.

For the implementation I tried to search, got a lot of questions answered but propably too much information as I got uncertain on some points.

1) I'd like to go low on the front channels and still not risk driving the Jordans beyond their excursion limits, ideally to 40-50 Hz so sealed would propably not work even if mounted against the wall ?

2) Would a reflex, ported lower than normally to compensate for the closeness of the wall work ?

3) Would a 1.5 setup where a second element would be joining in only at the lower end work or just be a waste of money?

4) At a close distance to the wall, would a BSC needed ?


Thanks,

Jan-Peter

 

[valleyman]

If you want small and wall mounted, your options are fairly limited.

The only enclosure types that are likely to work in this situation are closed and ported, though an aperiodic enclosure may suit you too.

Have a look here for a little info:
http://diyaudioprojects.blogspot.com/2008/07/diy-sealed-jordan-jx92s-bookshelf.html

That site has measure T/S parameters for the driver too which would probably be better to model with than the published ones.

If you want to reach down to 40-50 Hz, the only real option is ported. It may be worth considering a downward firing port as I wouldnt consider a rear port an option for wall mounted speakers and downward firing may give you some extra bass lift compared to front firing.

Even this though will not give you the deep rumbling bass of a typical HT setup with a sub - and I think no enclosure would be able to achieve this with the Jordan. As smallish FR drivers go, it's bass seems to be better than any but it will never shift as much air as a sub can.

A ported enclosure should give you bass into the 40s but the box size should be around 15L compared to around half that for a sealed box. Given your tastes and constraints then, maybe the smaller sealed boxes with a sub would suit better. I don't know if it's true of the Jordan's but FR drivers are often thought to sound better over the rest of the range when not pushed too hard in the bass.

WRT BSC, I wouldn't think you will need it given that they will be wall mounted, probably best to leave it out to start with, then you can always add it afterwards if you feel it is necessary

 

[J-P B]

Thanks,

I'll check the link.

Regarding a sub, I'm going to integrate one but hope not to have it run up too high.

J-P

 

[navin]

1) I'd like to go low on the front channels and still not risk driving the Jordans beyond their excursion limits, ideally to 40-50 Hz so sealed would propably not work even if mounted against the wall ?

2) Would a reflex, ported lower than normally to compensate for the closeness of the wall work ?

3) Would a 1.5 setup where a second element would be joining in only at the lower end work or just be a waste of money?

4) At a close distance to the wall, would a BSC needed ?

I would mate the Jordans (ported) with a tweeter. Jim Griffin G2si design can be considered. Maybe just the front left and right channels will need the tweeters.

you might still need about 3db of BSC (4ohms in parallel with 0.8mH).

 

[valleyman]

Thanks,

I'll check the link.

Regarding a sub, I'm going to integrate one but hope not to have it run up too high.

J-P

Well that link shows the FR plot of the Jordans in a little sealed box and they still go plenty low enough. f3 at 70Hz so the sub would not have to run too high at all

 

[gmilitano]

A 60Hz XO was to my liking. Yes, I suggest the BSC. I used about 4-5dB. Tweeter will help off axis response.

I still plan to convert this box to aperiodic.

 

[J-P B]

Thank you all for your replies,

I'll have to test a couple of versions starting with sealed.

Currently I'm just not sure about the Jordan anymore, a CSS FR125S would be A LOT cheaper (100 € less a piece, quite a lot for a set of 5). On what I'veread hear it doesn't seem it's that much worse and since this is the first non-car project could be a better start..

Jan-Peter

 

[GM]

Hmm, all things considered, the 125SR in a ~0.25 ft^3 sealed cab would be my choice since in theory it needs no BSC and can handle 120W transients without exceeding Xmax if at least an 80 Hz/2nd order XO is used. Like any 'FR' driver though, if the L/R mains and surrounds aren't toe'd in they will all need a tweeter to get an acceptable power response and the CC may need one regardless if not a solo seating area.

WRT driver sonic differences, I've done no side by side comparisons, though my memory of Jim Griffin's original JX92S and 3" TB monitors put them as slightly more detailed than the older FR125S I have. With these I found the need to notch out ~ an octave wide 'BBC dip' centered at 2 kHz due to the excessive 'presence' mixed into too many Jazz/Blues CDs IMO, though for movies they sound fine as is.

As always though, YMMV.

GM

 

[J-P B]

Thank you for the info,

Regarding the tweeter, I might add in one in a rebuild, as well as for example the 7" woofer from CSS for the main channels.

Looking through the different designs existing for the FR, the aperiodic seemed a possible candidate also. Is it suitable for wall-mounting with the opening down?


Jan-Peter

 

[J-P B]

Just an addition to give a better sense on what I'm looking for:

The room is approx 5m x 7m (opening into two corridors). Seating approx 3-4m from wall, in a 2m wide are.
Amp is a Onkyo receiver (SR-875), not the best in sound but has the video-scaling capabillities I wanted, due to arrive anytime now.
Sub is a currently Velodyne CHT-10 (Ok for my taste) in my stereo system would be swichted to the HT.

J-P