The Frugel-Horn Project

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
frugal-phile™
Joined 2001
Paid Member
renfrow said:
I have a pair of the alnico SP-10F5A (Sony?) FE103As coming in the mail and I'm wondering if the Frugal Horn would be a good fit for these?

Pictures?

i have found a significant potential for variation on the spec on this class of driver, Typically these have even higher Q than an FE127e, but that is only on average -- it will depend on your specific age. Alnico is suseptable to losing its magnetic strength over time, or is knocked which will change its parameters (it would be nice if someone started offering a recharging service)

Sony didn't make there own drivers, but the Sony's i have had have been either a 120mm class Foster or the holey basket Coral. I have measured holey basket Corals that should work, i haven't measued the Foster (but i do have a single in a drawer somewhere). Both sound quite special.

dave
 
Note: I don't have these in hand, this is the picture from the auction:

Tom.
 

Attachments

  • c920_1.jpg
    c920_1.jpg
    33.8 KB · Views: 678
frugal-phile™
Joined 2001
Paid Member
renfrow said:
this is the picture from the auction:

Was there any other data in the auction?

I've not seen this variant before. From the basket & the surround i'd suggest Coral OEM. The picture is tiny, but there is indication that these may be suffering from "Stiff Surround Syndrome". You will know pretty quick once you get them in your hand and push the cone in and out. If that is the case then these are mid-tweeters unless you can fix the surrounds. So far i have had no luck, but a client gave up a technic he found worked (and it sounds like it could). He says it can tend to get messy thou. Once it warms up i will give it a try (i have 30 or so drivers that have SSS and are dispensible before i get into the ones that would be really worthwhile saving.

dave
 
frugal-phile™
Joined 2001
Paid Member
That the surround is not stiff is a good thing... if we knew how to interpret them that last number would probably tell us exactly who made them. My best guess is that these are a Coral (or National variant, but the bezel shape also suggests Atomix (not one of their hi-end ones thou, those would have tell-tale ribs on the cone.

Can you measure them?

dave
 
latest frugel build in the UK

Hi all, thought you'd all like to know that I've just completed a frugel horn (with wedgie, baffle thingy and the prism thing as well!) Now I need to sort the compression chamber out! Any ideas on the best way to do this? I'm using an fe126e and according to the plans 2.2 litres is the target volume for this driver, is this correct? is there an accurate means of checking the volume is correct other than by ear?
Any advice greatly appreciated!:)
 
frugal-phile™
Joined 2001
Paid Member
Re: latest frugel build in the UK

Myron said:
Hi all, thought you'd all like to know that I've just completed a frugel horn (with wedgie, baffle thingy and the prism thing as well!) Now I need to sort the compression chamber out! Any ideas on the best way to do this? I'm using an fe126e and according to the plans 2.2 litres is the target volume for this driver, is this correct? is there an accurate means of checking the volume is correct other than by ear?
Any advice greatly appreciated!:)

Good to hear another Frugel-Horn has life :)

2.2 litres is our best guess so far. To refine that someone will need to be prepared to go thru some tedious tests. A suiable room, and some measuring kit will be required...

What you would look for is a smooth hand-off between the front-radiation and the horn-output.

The suprabaffle pushes the point at which baffle step starts to appear down to a certain frequency (in the neighbirhood of 250-350 Hz. The size of the CC determines the HF cutoff of the horn. The idea is to have the output of the horn go up just enuff to meet where the supraBaffle pushes the BS down in frequency. So one would adjust CC size measure. Change CC size, measure, until a volume was found where there is a smooth hand-off from the front/IB radistion, to the rear horn radiation. This is further complicated by the phase vector difference caused by the path-length the rear radition takes*... in a perfect world we could also adjust the supra-baffle size (which at the moment is an educationed guess compromised by what is aesthetically acceptable). And even then the theorectical might not sound best.

*ideally the distance is (2n+1)/2 wavelengths of the CC chamber cutoff (n=0,1,2, 3...)

So yea, until someone musters the resources to do this it is by ear. Further complicating that, is that adding stuff to the CC (particularily irregular stuff, could well improve the sound by breaking up CC standing waves and reducing reflections back thru the cone)

dave
 
latest photo's

Hi all, see the photo's of my recently completed Frugelhorn build, it's a fairly straightforward version based upon the full build, only real difference is the suprabaffle which is made using two stepped runs of 20mm quadrant, (Dave's version using the table saw would have been quicker but I had the quadrant lying around!) I've also bunged the voids up with expanding foam so the sides are solid. The wedgie did make the build easier!
Fe126e's are part run in, as you can see from above I just need to sort the compression chamber and away we go.
Photo no1.
 

Attachments

  • image1.jpg
    image1.jpg
    18.6 KB · Views: 572
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.