Goodbye JBL 4343

[Hari Iyer]

Thin walled resonance can be further dampened internally and tuned (no idea how this is calculated)

Panel resonance can me measured even by your mobile based accelerometer.

Cabinet resonance can be measured by measuring impedance and it's phase.

I am planning changing my OB if the new design is within my budget and if I can salvage some cost out of my current baffle. I shall be considering either mango wood or spurce wood for my built to be within budget. This is the first time if I built, I shall not be using any mdf, particle board etc.

 

[Rajiv]

Rajiv, where do you get jackfruit wood?

Prem, you should be able to get it from Kerala. Panruti in Tamil Nadu also is a big center for Jack fruit.

https://www.aknwoodtradingcompany.co.in/jackfruit-wood.htm

Regards
Rajiv

 

[Analogous]

Panel resonance can me measured even by your mobile based accelerometer.

Cabinet resonance can be measured by measuring impedance and it's phase.

I am planning changing my OB if the new design is within my budget and if I can salvage some cost out of my current baffle. I shall be considering either mango wood or spurce wood for my built to be within budget. This is the first time if I built, I shall not be using any mdf, particle board etc.

Thanks Hari, What’s the current thinking and approaches about internal bracing and lining?

 

[Hari Iyer]

Thanks Hari, What’s the current thinking and approaches about internal bracing and lining?

I don't do internal bracing as they occupy volume and interface with waves. I do interlocking joints at all 6 corners for rigidity. Most BR & TL ( mass loaded) speakers sound good with just a 4mm to 6mm felt lining without any stuffing IME.

 

[prem]

To begin with I will be going with Goodman Axiom 80 designed box. I thought about it a lot and felt I should hear the driver in the way the manufacturer thought was best. Yes there are options of horn or OB but those I can look at later if I wish to.

In terms of box material I will be using 18 mm poplar plus eucalyptus with Gurjan face plywood for back panel and side walls. For front panel I may use the same or go for 18 mm Russian birch ply.

For the amp I have finalised Thoress F2A11 integrated. Also Thoress will be providing me with two bass boost options designed for the the Axiom 80 driver and one flat option. The regular F2A11 integrated does not come with these bass boost options.

 

[keith_correa]

Do you know the output impedance of the F2A11?

 

[prem]

I will be using the 16 ohm tap. Is that what you are asking? There is also 4 ohm and 8 ohm taps. At 16 ohm I get 25 db gain. At 8 ohm I get 22 db gain

Damping factor is less than 10

 

[prem]

Keith, output impedance is approx 2 ohms. Thoress just replied

Yogibear he won’t give all those details.
Anyways what does primary mean?

 

[Kannan]

Do you know the output impedance of the F2A11?

it has 4, 8 and 16 ohm taps

 

[Kannan]

Prem, any idea what primary they will be using ? (If they disclose that)

Details are in the linked pdf.
It uses in-house C-Cores for primary

https://www.thoeress.com/downloads/thoeress_f2a11_integrated_description.pdf

 

[prem]

Thoress OPTs are considered among the finest in the world. He winds it himself. In the past he used to do it for a few select people. But now he doesn’t. He also makes his own power transformer.

His understanding of audio engineering and his attention to details and quality is something else. What I like is he keeps everything very simple and doesn’t get carried away by new fads.

Most importantly he is a complete music buff who attends concerts pretty much every week. He has been doing that since childhood. His exposure to live music really helps him in his design.

 

[keith_correa]

Keith, output impedance is approx 2 ohms. Thoress just replied

Perfect for the Axiom 80!

 

[prem]

Thanks for sharing. It’s not too different from the Tele OB. I have been exploring spruce panels too

 

[Hari Iyer]

Spurce and Pinewood are very similar

 

[prem]

No Hari. Musical properties of the two are very very different.

 

[Yogesh]

I haven’t enjoyed a video so much in weeks!

Another even more satisfying one!

 

[prem]

It’s always a toss up on how much you want the wood to resonate and how inert do you want it to be. Getting that balance is a challenge.

 

[Kannan]

https://www.hifivision.com/threads/the-end.90512/

@prem are you traveling in space? It seems a decade has passed in less than a year

 

[prem]

I think it’s the coronavirus vaccine

I didn’t know it had this side effect too.

 

[grindstone]

Thanks for sharing the ride. I really respect how you approach all these things, @prem.

Not sure if you're making the friction-loaded cab with the ARU or the old reflex one, but thicknesses in my stuff are listed from 1" min for the early corner reflex to 7/8 min for the 1958 catalog ARU version. The 1960 catalog has the same 7/8 but a footnote for a min 3/4 on that same ARU 180 cab, FWIW.

Not sure if you've measured the drivers (or Hari might have) etc but if it's worth anything, I think I have at least some impedance and FR curves stashed somewhere. That wouldn't get everything you need to do sims, but almost everything.