Radio Shack 40-1197 (aka FE103)

[planet10]

With regards to the stuffing on the proto-1197-ml-tl, there are no details regarding stuffing.

0.36 lbs

does using two drivers increase the efficiency?

Sort of

You also mentioned that the height of the enclosure is critical. How is this height determined? Is it based on experimentation, or can software be used to model the enclosure. I have been playing with speaker workshop .. is this approprite or do I need something different?

GM (the other one) simmed that box using Martin Kings sw. The driver distance from the end of the pipe is critical because that is what causes the cabceling of the 1st ripple.

dave

 

[planet10]

The old blue box 1197s were of 90db efficiency, the newer ones are less. Two drivers in parallel are usually calculated as having a +6db increase.

I see Tim, that you are still in the grasp of that myth... 2 drivers gives 3 dB.

Differences in amp power due to change in impedance, may (but rarely) give you another 3 dB of volume.

dave

 

[Timn8ter]

I see Tim, that you are still in the grasp of that myth... 2 drivers gives 3 dB.

Differences in amp power due to change in impedance, may (but rarely) give you another 3 dB of volume.

dave

Thanks Dave. The education continues.

 

[Timn8ter]

Re: Extended Range Drivers

Does anyone have any experience with the PE Pioneer extended range driver?

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=269-568

How would this driver compare to the 1197. Based on the vauge 1197 specs, the pioneer seems to have a higer resonant frequency and a lower efficiency.

Any comments ... nice price on the pioneer driver.

Not even close. Here's the FR on a raw 1197.

 

[gmilitano]

Re: Re: Extended Range Drivers

Not even close. Here's the FR on a raw 1197.

Wow, the 1197 is much much nicer! I guess you do get what you pay for.

Did you measure that response yourself?

When using the 1197, do you typically low pass at 9k to avoid that peak between 9 and 14kHz

Cheers,
GM.

 

[planet10]

Re: Re: Re: Extended Range Drivers

When using the 1197, do you typically low pass at 9k to avoid that peak between 9 and 14kHz

Be intesting to see if a tweaked driver has that peak ... at any rate it is only there on axis... if you don't point the privers directly at your head, it isn't going to be s big problem.

dave

 

[gmilitano]

Re: Re: Re: Re: Extended Range Drivers

That graph is from the Single Driver Website and is an untreated driver. Better response is possible by treating the cone, damping the frame and using a phase plug.

Ok, this is getting more complicated than I thought.

How do you "treat" a cone? Do you mean something like waterproofing?

Is damping the frame is using that sealant (ductseal) that Dave mentioned.

What is a phase plug?

I hope I am not annoying you fellows.
GM.

 

[markp]

A phaseplug is a extension of the pole piece that sticks out instead of a dust cap. It is ususally cone shaped but not always. It can be made of rubber, metal, or wood, etc.. and is used to shape the response of a driver on and off axis.

 

[Timn8ter]

Should we start a thread about the venerable 40-1197?

 

[Timn8ter]

RS 40-1197 discussion

I thought I should start a thread about this driver as an off shoot of the Tangband W3-871S thread. There were some questions presented that were off topic for that thread. I hope Planet10 kicks in with some info too as he has a fair amount of experience with this driver. This is the other thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=33636
Many users of the 1197 have used Dammar thinned with turpentine to treat the paper cone. Other treatments mentioned have been "puzzlecoat" or Weldbond thinned with water. The frame is stamped and can cause resonance so a minimum of some modeling clay on the frame just above the magnet helps. Some brave souls have placed felt on the inside of the basket legs. Removing the dust cap and installing a phase plug can help HF response.

 

[gmilitano]

Re: RS 40-1197 discussion

Removing the dust cap and installing a phase plug can help HF response.

With regards to the phase plug, is this a good idea? Given the cost of the plugs, would the money not be better spent on a tweeter which would help the HF response and extend the response to 20 kHz.

 

[Timn8ter]

For me, the phase plug smoothed out the response. Adding a tweeter wouldn't help this. The only time I miss the upper response is if I A-B with something, for example, side by side comparison with the Jordan JX92S. Dollar for dollar a tweaked 1197 is hard to beat. A good tweeter would probably cost more than the 1197 or the phase plugs.

 

[SY]

What did you do for a phase plug? Balsa and a lathe?

 

[planet10]

Re: Re: Re: Re: Re: Extended Range Drivers

What is a phase plug?

Blatant Promo

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3095290500

dave

 

[Timn8ter]

What did you do for a phase plug? Balsa and a lathe?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3095290500

 

[gmilitano]

For me, the phase plug smoothed out the response. Adding a tweeter wouldn't help this. The only time I miss the upper response is if I A-B with something, for example, side by side comparison with the Jordan JX92S. Dollar for dollar a tweaked 1197 is hard to beat. A good tweeter would probably cost more than the 1197 or the phase plugs.

I was thinking to cross over at 9kHz to avoid that peak. Dave also mentioned that suitable tweeter will cost more to ship than the cost of the tweeter.

To me this make sense, you avoid the peak and extend the range. is my logic flawed?
GM.

 

[Timn8ter]

It might be good to keep all the factors in mind. We're talking about a driver than costs $18CA for a new one, I paid $30US for four older ones delivered. As good as they are they can't be expected to perform as well as a Jordan. If you're going to spend $50 or more by the time you add a tweeter and crossover you're going to be better off buying a Fostex FE166.

 

[planet10]

As far as i'm conncerned, the most important improvement with a phase-plug is the removal of (most of) the last vestiges of te upper midrange "honk" (ie male voices) that all the variations of this driver suffer from (in comparison to a tweaked FE103A, you can even hear that the FE108 has this).

A side effect is improved high frequency dispersion -- you do get a small bit of extension, but that is not the important thing.

dave