|Hello and welcome to my Frugel Horn Mk3 page, the one after this is about my Gain Clone build
The speakers were designed by a team on DIY Audio perhaps the most successful and widely made single driver DIY speakers ever designed, certainly sounding a lot more than the sum of its parts. The build thread can be found here, FH3 Builds where the plans can be downloaded.
The design is such that should anyone try to manufacture and sell it without paying the quite small fee to the designers the speaker will be spotted by enthusiasts
I first heard the FH Mk3 at Colin Topps (Toppsy on DIY Audio) house after he very generously invited me round to listen to the speakers.
To say that I was impressed is putting it mildly it affected me for days afterwards. I thought that despite the difficulties and my lack of expensive tools I would have to make a pair.
The pair you see to the left are Colin's own with Ash veneer and the Mark Audio Alpair 7 drive units. Colin will gladly demonstrate these to anyone interested.
Frugal or Frugel Horn Mk3 Do It Yourself high end horn loaded loudspeaker DIY FH Mk 3
This cutting drawing was my first step, the sheet size is 1220 x 2440 mm [4Ft x 8Ft] 18mm MDF.
I went into B&Q in Chesterfield and met Shane who does the cutting, he very kindly made a cut on scrap to show me first and assured me that the cuts are repeatable, square and parallel. He then cut the above from 18mm MDF and the cost was about £17 including the cutting.
The next problem for me was the inset to obtain the 5 degree angle, using 5.00 degrees 900.00 mm and 90.00 degrees [the .00 is important] I went to http://ostermiller.org/calc/triangle.html and got 78.7 mm for the inset on the sides. Once I'd established this inset I drew the outline of the speakers on the sides, 2 from the drawing and 2 mirrored so that all 4 sides had the drawing on them.
The tools I use just simple home stuff please note the masks, MDF is not very nice stuff and the dust is harmful, I did all my cutting outside. The only tool I bought was the angle thingy with the orange handle, set at 5 degrees I used this to check the angles I planed into the baffles. In the background you can see the baffles and the drawn on sides.
I haven't got any clamps apart from some small 'G' ones so I had to resort to little tricks to glue them up. From the left; jammed up against a cardboard box to glue the rear baffle to the top, weights to hold the baffles down, a wedge to hold the 1/2 round piece at the bottom of the taper, small clamp to hold the bottom of the taper, and more weights to hold the baffles in place. The speakers are quite heavy the pressure for the gluing does not have to be that great and with care the whole thing will assemble square. I cut each baffle piece a few mm longer and planed it, tried it, planed it again until I got a good fit. The front baffle which I fitted last took some time to get exactly right and just so that it fitted in with a little bit of resistance. The hole you can see on the right is for the cable connector.
If you decide to buy a flat pack what you see in the pic above is really all you will need to assemble them.
Time and patience is the essence of doing this, as DIYer's we have plenty of time, 1/2 Hr per day for ten days will soon see this done and if you've never done anything like this before you have time to think about what you are going to do the next day.
The speaker hole with a chamfer at the back.
I used three layers of hanging basket felt around the rear of the speaker area. Note the lollipop stick 'repair' to the speaker hole, I cut it a bit too big and had to do this to get the screws in. You may also notice that just to the left of the hole I have had to make a butt joint in the baffle this was filed square and glued so that it can hardly be seen, I'd made the speaker hole too near the top.
The stuffing I used to begin with, it's pillow filling. The Blue Tak is to hold the sides on while I ran the speakers in and then alter the stuffing accordingly, this works very well indeed and seals the speakers completely and it is quite difficult to remove the sides.
I ran them in for 2 weeks quietly connected to a tuner and Radio 3. I am now using them at quite some volume and am finding that I must listen to my entire recording collection, hearing them again for the 'first' time.
I bought the drive units from Spectrum Audio in Germany, Wolfgang whom I exchange emails with is very helpful indeed.
My first true audio experience was at a work colleagues house, he had a pair of Lowther Acoustas with PM6 units, I was amazed at the sound and it has stayed with me ever since, this is what I hear now from the FH3's.
I must thank the designers for creating this wonderful speaker and Mark Fenlon for designing and making its perfect partner the MA CHP-70.
I live not far from M1 Ju29 anyone who would like to hear my pair are very welcome to contact me, Jim Read
More will appear on this page when I finally glue the sides.