Thanks. The calculations on those 4 inch did not look very good... maybe something for a future project with more freedom in cabinet size.
As for the jordan's: yes of course. but it is just too much money to start off as a 'first try'.
The larger box would allow one to get more out of the Alpair 6.2, my personal pref is the paper version. And i would attempt a vented alignment to max out the advantage of the larger than expected box and using the Alpair.
Sealed sims for both A6.2 attached.
dave
Attachments
The aura are likely the winner in any contest where getting bass out of a 3" driver (althou it would be a tight contest if you could vent the A6p). It lacks the finesse & DDR of some of the other drivers, but i would say that, at its price, it is an undisputed value leader. And with the continuous concave sandwich cone, very pretty IMO.
dave
...and unfindable in any european webshop... and with shipping costs more than doubling the price if I order them in the US, the value contest is shifting a bit.
I can get the Aura's for about 60 USD shipped. Or I can buy here at home the Alpairs (169 eur/pair) or the Fountek FR88EX for 80 eur/pair and the Fostex for 100 eur/pair. What is the expert opinion on value for money?
(p.s. I can get the Alpair 6 first generation for 140 eur on sale...)
For venting I would need a really small BR tube (calculation showed about 2cm diameter and 12 cm long). Is that about the same values you have in you designs?
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Alpair vrs Fostex http://www.diyaudio.com/forums/full-range/196061-3-driver-audition-fostex-mark-audio.html
I put the Fountek a step down from any of the above. I bought 24 of the Fountek when Fostex was transitioning to the new driver. I put them on the back shelf (have some left, i'm happy to pass them on -- i bought them before the price increase that pushed them beyond my consideration).
The old Alpair 6 was, IMHO, the best of the 1st gen Alpairs, but still found they had a bit of the HF edginess that i found unaccepatable in the Jordan JX92. I'd choose FF85 over them.
dave
I put the Fountek a step down from any of the above. I bought 24 of the Fountek when Fostex was transitioning to the new driver. I put them on the back shelf (have some left, i'm happy to pass them on -- i bought them before the price increase that pushed them beyond my consideration).
The old Alpair 6 was, IMHO, the best of the 1st gen Alpairs, but still found they had a bit of the HF edginess that i found unaccepatable in the Jordan JX92. I'd choose FF85 over them.
dave
Because the were EOL some years ago and Madisound bought up all the available units (one of the reasons the price is so good).
dave
with 3.3 litre (about 3 litre once vent & driver vol accounted for) is a big big for the cleanest alignment for FF85wk. I suggest 25mm D x 54 mm long and add a half litre of something solid. Given the penchant for a sphere to have an extrem pressure area at the centre, a long cone or cyclinder attached to the back of the driver magnet would go a long way. Styrofoam would work (i'd coat it in PVA).
dave
dave
You do need to make as close a calculation as possible to determine your available volume. Perhaps you could fill the sphere with some sort of dry media, Freeze died peas, wood shavings or..??? Craft a box at 100mm by 100mm, with an open top & see how high up it gets..??? A flat circular baffle covering the "opening"....If ported, I would opt for a port pointing down, slightly off from 90 degrees. And yes you need to get it sealed as best possible, any leakage variations will throw off your calculations.
Just throwing out some ideas here.
___________________________________________________Rick.......
Just throwing out some ideas here.
___________________________________________________Rick.......
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To do the volume measurement I used water. And i repeated it 4 times and took the average value. So I am quite certain about the 3.3 liters (without driver or BR port). My error should be less than 0.1 l. After all, i'm a physicist working at a company whose motto is 'measurement systems'...
The seal is already provided by the enclosure used, as long as I cut my baffle out in the right size.
I think I'll start with a sealed enclosure, then vent it a bit by putting washers underneath the screws of the driver (0.5mm or so), and then port the baffles. this way with one piece of woodwork I can try several things proposed here. Once I'm happy, I'll leave it as is.
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Ok. The fostex are ordered. I bought some MDF and some pipe with and inner diameter of 25mm.
In the meantime reading up more on speaker building, and of course more question arise. For example: should I chamfer the inside of the baffle where I will mount the driver?
And the speakers were stuffed with soft material when I took them apart. I was planning on putting the same stuffing back in. Is that a good choice?
And should I countersink the driver?
In the meantime reading up more on speaker building, and of course more question arise. For example: should I chamfer the inside of the baffle where I will mount the driver?
And the speakers were stuffed with soft material when I took them apart. I was planning on putting the same stuffing back in. Is that a good choice?
And should I countersink the driver?
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IMO always an excellent idea on smaller fullrangers such as the 85s, you do need to be careful to retain enough material core for mounting screws ( I find #5 x 5/8 or even 1/2" is more than adequate for these little guys)
time will tell how much and type will give best results - I'd opt for less to start with
the mounting flange on these is thin enough and gently radiused that countersinking is likely far less critical than with say a Alpair6, but it can make for a tasty project - it will be a test of either your freehanding or pattern making skills
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