My first speaker building project

[gobble]

I was going to take my time opening this thread, then suddenly two posts in another thread inspired me for a quick solution. Since I may eventually move on to a proper cabinet if these solutions do not work, and since my speaker drivers are different and I do not want to hijack the OP's thread, I am continuing a reply to their posts on this new thread.

Firstly a brief intro of the drivers from

JXR6 HD

It is the world's widest bandwidth 2 inch driver and represents the leading edge of moving cone driver design.

The JXR6 HD features the unique Jordan Controflex metal cone in an improved suspension which allows this unit to effortlessly cover the range 100Hz to 30kHz. The resonant frequency of this unit is 80Hz which allows a single unit, in a 1 litre, totally enclosed box, to form the basis for a superb, satellite/sub-bass system. Matched to a suitable powered woofer, a truly discrete, high end, audiophile sound or home cinema system is now possible for the first time.
...
The low frequency response of the JXr-6HD has been extended to a remarkably low limit to enable its in-box performance to be directly matched to appropriate, high quality sub-woofers. To achieve this, the conventional rear suspension has been omitted and the system resonant frequency and 'Q' values are set primarily by the acoustic suspension provided by the volume of air enclosed within a small box.

Another well written link: jordan jxr6 hd main driver | Metier

Now I got 4 of these I plan to connect in series to make 8 ohms and tube amp friendly. Also I believe two drivers will add more body to the low freq and sound similar to the output of a single 4" driver.


Also I originally planned to taper the frequency response of these drivers using the volume of the cabinet to around 100hz at -3db. And use the sub for everything below with a slight compromise on audiophile 2.0 SQ. The biggest motivation being freeing up 4ftx7ft space in my living room - These speakers sound best closer to the wall.


The cons of using drivers in series in lay terms is that the amp does not drive both the speakers directly and hence will not control the 2nd speaker well enough as it is behind the first. The load seen by it is not the same as the two drivers in parallel.

If you google there are a few design attempts using these drivers on various forums - but I don't want to get there or begin with that yet as I will explain below. Particularly right now inspired by these posts on the thread new-try-fancy-looking-cheap-diy-speaker to attempt a solution

Quite a radical design but interesting. For your option I, what about shell of a 'dhollak' or 'Naal'. Similar principle but lighter because of wood and tough.

Interesting!! But the immediate questions are:

Q1. Does the shape of the Dholak contribute to or represent a good speaker design? I plan to cut a rectangular hole into it to mount a rectangular block holding two pairs of these 2" drivers, with the speaker terminals mounted on one side where the leather skin would have been. There would be no straps for tightening the drum of course.

Q2. If I leave the insides rough hewn and with the properties of Sheesham wood - would it reduce the effects of resonance? There was an earlier thread and a post that mentioned an approach to speaker building that went by the principle of moving resonant frequencies within the cabinet into a range where they do not matter. I presume the Dholak being made to be a "resounding" percussion device, I could use that property here to audiophile benefit? Or progressively damp it from within to tune it? Alternate woods to use and some comments on the properties of Sheesham wood vs other wood used for Dholak

Q3. A 5 to 6 ltr cabinet would be approximately feasible for a Dholak would it not?

The speaker was set up on the big size earthen pot. Sealed around using cycle tube. .

I could find a potter who can make a matka with an extra large and rectangular mouth for it with two holes for the speaker terminals. They speaker stands would be two Auto-Rikshaw tires on a pair of 2 ft logs of timber wood placed against the wall.

Q4. A 5 to 6 ltr matka would be quiet feasible would it not? What diameter would that be for a perfect sphere?

Or

I know a ceramic and pottery hobby class in Indira Nagar nearby. Either I could outsource building a ceramic tall narrow and deep vase/cabinet to one of these hobbyist, or join the class and build my own in a months time (or longer). Possibly this could match the properties of the Shigaraki used by 47 labs in their dac? hyeah: Or maybe the raw material also matters but then it could be close.

Q5. Lastly - will two fullrange drivers per speaker make a single point source? How should I position them to mimic a single point source as closely as possible?

When Tijimon came over he setup a driver in a cardboard shoebox lid as a baffle and it was wonderfully mellow and smooth sound - one to die for. I have high hopes for these drivers.

Looking forwards to some insightful advice. As you all know, I am zero on speaker building theory and experience. I do have links to follow, will progress on that as the project moves ...

TIA
--G0bble

 

[Sumanta]

Gobble,
Where can I get these drivers and how much they are?

I want to use earthen pot rather than a musical instrument to save money and the dholak. Plus, I can always try with different shape and size of earthen pot.

Coming bak to the driver, with this driver and a 6 inch or so woofer, I would like to follow pluto design. With OB design, I have understood the beauty of spatial sound which I do not want to miss.

 

[sbg]

Pottery R&D for speaker enclosure.
clay speakers

This was in news, couple of years back.

But I can give tips on how to make port holes in these pots without breaking the pot.
....
Let me check if I have any of these old snaps.

 

[Hari Iyer]

I checked the TS parameter of this 2" driver and found the Qts and Qes to be very high for this driver. Hence dont think it will be suitable for a TL design, neverthless you can try it out as it will be less expensive for you to build with them considering other options that you mentioned. If you would like me to design the cabinet for you then do let me know and i can be of assistance if TL is in your mind. But with TL you can have only one driver per box and you can get the complete benefit of the full range driver for the entire frequency band. I agree with you to cross-over the speaker at around 100Hz (ie above the resonating freq of the driver) to prevent non-linear operation below the driver resonating frequency. This will allow greater power handling and smooth even mid-range response and a simple 1st order filter can also server the purpose.

Wishing you all the best with the final outcome.

Cheers,
Hari.

 

[gobble]

Gobble,
Where can I get these drivers and how much they are?

I want to use earthen pot rather than a musical instrument to save money and the dholak. Plus, I can always try with different shape and size of earthen pot.

Coming bak to the driver, with this driver and a 6 inch or so woofer, I would like to follow pluto design. With OB design, I have understood the beauty of spatial sound which I do not want to miss.

Sumanta

I purchased it from Solen Solen Electronique Inc.

I was thinking of the Bandor-150 8" driver for bass in a side firing design using a tall narrow deep cabinet - in case the subwoofer issue I have is not resolved. I can;t find that thread on another forum, but apparently somebody thinks for good reason that with a simple crossover using only an inductor it will pair well. There was also a pic of a cabinet like the one I described...

I checked the TS parameter of this 2" driver and found the Qts and Qes to be very high for this driver. Hence dont think it will be suitable for a TL design, neverthless you can try it out as it will be less expensive for you to build with them considering other options that you mentioned. If you would like me to design the cabinet for you then do let me know and i can be of assistance if TL is in your mind. But with TL you can have only one driver per box and you can get the complete benefit of the full range driver for the entire frequency band. I agree with you to cross-over the speaker at around 100Hz (ie above the resonating freq of the driver) to prevent non-linear operation below the driver resonating frequency. This will allow greater power handling and smooth even mid-range response and a simple 1st order filter can also server the purpose.

Wishing you all the best with the final outcome.

Cheers,
Hari.

Thanks Hari. Yes this driver is designed for a sealed enclosure only.

Edit: @Sumanta, this will not work with an OB design. But it reputedly has a wide sweet-spot with pinpoint stereo imaging and an enveloping sound.
--G0bble

 

[Sumanta]

Edit: @Sumanta, this will not work with an OB design. But it reputedly has a wide sweet-spot with pinpoint stereo imaging and an enveloping sound.
--G0bble

I had thought of using it for Pluto kind of design only, like one in my post.

 

[doors666]

why would you look for this drivers parameters for tl design. wouldnt it be the woofer's params that would matter for the tl. whats the point of putting the jordan in a tl when there's a woofer to handle the low end anyway, not that it cant be done, but seems unnecessary.

 

[t.antony]

IMHO it's a good idea to go with the sealed box option as this driver seems to be better suitable for that.

To take the full advantage of the size of this driver and to emulate an acoustic point source, it's better to use single driver per speaker, hope your tube amp can handle that.

A sphere is not a good shape for the speaker internal cavity, at the same time it's one of the best exterior surface possible for a point source design, Take a look at this interesting design, don't miss the video towards the end of the page.

Bon Bon Sound Round Wooden Speaker from Japan | Craziest Gadgets

May be you can use your speaker stands for a better purpose

 

[pupupuchi28]

In my opinion:
Pros of Sphere:
- Strong enclosure even with less thickness
- 'No' internal standing waves > no coloration of sound > flat response (given driver has a flat response)
- Single point source > accurate imaging assuming use of single driver
- According to me they are the best looking speakers
Cons
- A strong resonance fs but can be tammed with 'proper damping' in the middle, if the sphere has a 'tummy' in middle (imagine mridang). Less prone to spheres without a tummy (for e.x naal which is fairly straight)
- Need to have polished internal surface like the external one. Very hard to achieve.
- Driver matching is very important for a particular type of sphere.

A sphere with the maximum diameter at the place where the drivers are mounted avoid all demerits of a spherical enclosure.

 

[navin advani]

Now I got 4 of these I plan to connect in series to make 8 ohms and tube amp friendly.

Also I originally planned to taper the frequency response of these drivers using the volume of the cabinet to around 100hz at -3db. And use the sub for everything below with a slight compromise on audiophile 2.0 SQ. The biggest motivation being freeing up 4ftx7ft space in my living room - These speakers sound best closer to the wall.

The cons of using drivers in series in lay terms is that the amp does not drive both the speakers directly and hence will not control the 2nd speaker well enough as it is behind the first.

Q1. Does the shape of the Dholak contribute to or represent a good speaker design?

Q2. If I leave the insides rough hewn... I presume the Dholak being made to be a "resounding" percussion device, I could use that property here to audiophile benefit?

Q3. A 5 to 6 ltr cabinet would be approximately feasible for a Dholak would it not?

Q4. A 5 to 6 ltr matka would be quiet feasible would it not? What diameter would that be for a perfect sphere?

Q5. Lastly - will two fullrange drivers per speaker make a single point source?

A sphere is not a good shape for the speaker internal cavity, at the same time it's one of the best exterior surface possible for a point source design,

Sorry for jumping in a little late.

I have used the JX92 and the older Jordan 50mm Watt module (sens was 81-82db/1W).

The Jx6 was designed to be used in arrays of 4. see links
http://www.tnt-audio.com/jpg/nonsuch.jpg
http://live.audiogon.com/i/rmf2007/f/1192929031.jpg

A Dholak ot Tabla produce sound not reproduce it. I would suggest damping the resonance so only the driver is producing the sound and the dholak is not colouring it.

A circular baffle has the edges all the same distance from the driver. Just ask Michael Barnes of Norh. This baffle can be difficult to compensate for. If one wanth no edges the baffle neds to be very small ompared to the diameter of the sphere.
http://www.susan-parker.co.uk/susan-speaker-sphere.htm
http://www.diyaudio.com/forums/multi-way/159151-ikea-spherical-speakers-first-build-done-5.html

5-6 liters look a little large. 2 liters per Jx6 is enough.


The Jx6 has limited SPL capability (size and sensitivity) and if used in arrays of less than 4 should be limited to 200Hz+.

Unless you have an OTL amp the amp's OPT should have 4 ohm taps as well as 8 ohms taps so drivig either a 4 ohm load or 8 ohm load should not be a problem. BTW I have not seen OTLs drive 8 ohms either.

2 fullrange drivers will approximate a point source at low frequencies. However it will only be an approximate never an exact point source. Single Jx6 can be used for nearfield monitors. I dont think they have the capbability to drive large rooms.

BTW 4x7 feet freed up? wow! were your existing speakers that huge?