Project BIG

[HoopsOnToast]

I was looking for something big, ugly and efficient to try with the Decware but nothing really took my fancy that was about so went down the diy route once more, with the arrival with a pair of Fostex FF225K drivers.

These are around 96-97dB/1m with a low QTS of around 0.16 and low moving mass.

The plan is to build a BiB cabinet similar to the one I built for the Veravox drivers a good few years back (showed at the first Scalford) but they will be bigger.

They will be roughly 68" tall, 10" wide and 14.5" deep. They have a single partition inside that is a simple horn / tuned pipe hybrid.

I have had these drivers previously in the Jericho horns and they had dynamics/attack to die for, just lacked some low bass to go with the excellent mid-bass. These should solve that problem, placed in the corners we should get pretty flat down into the 30Hz area! :shock:



Fostex FF225K by RSdesignUK, on Flickr



Fostex FF225K by RSdesignUK, on Flickr

Compared to the current Veravox 5S drivers:



Fostex FF225K & Veravox 5S by RSdesignUK, on Flickr



Fostex FF225K & Veravox 5S by RSdesignUK, on Flickr



Fostex FF225K & Veravox 5S by RSdesignUK, on Flickr

The plan is to get the wood cut early next week, routing a hole for the drivers might be a problem but I will come to that when I get there. The plan is to cover them in speaker grille type cloth so the blend in with the foam bass absorbers behind.

The only next thing is to choose a supertweeter, as these roll off from around 10kHz so I will only need something above that, but finding an afordable ribbon tweeter that will do ~97dB is not as easy as I thought.

I was thinking of maybe a cheap CD like the Celestion CDX-1415 that has been mentioned before, not sure about the horn/waveguide though.

Any ideas?

 

[awkwardbydesign]

Fountek cd2? http://www.fountek.net/products.asp?id=45

 

[HoopsOnToast]

Only problem with those are they are ~£100/ea, bit much really. The Fostex FT17 is quite cheap but read mixed reviews of its performance.

Ideally I would like a ribbon but not too fussed at this moment in time.

 

[awkwardbydesign]

I know, the price puts me off too.

 

[awkwardbydesign]

Did you see this thread? http://www.diyaudio.com/forums/multi-way/36097-fostex-ft17h-hurts-my-ears.html

Or a HiVi planar? I've used the little RT1.3 and found quite sweet. In fact I may go back to one. You will need something more sensitive, though.

Oh, and I used a pair of Monacor ribbon (?) tweeters many years ago; they sounded pretty good at the time, but I don't know if the current ones are the same. http://www.ebay.co.uk/itm/One-95-mm-Diametrer-Ribbon-Tweeter-Audiophile-Quality-/300949422403?pt=UK_AudioVideoElectronics_HomeAudioHiFi_HiFiSpeakers&hash=item4611fbc143

 

[HoopsOnToast]

Wow, thanks very much Andy, those would be ideal!

What sort of fit/attachement are they onto the CD?

You must spread some Reputation around before giving it to ADPully again.

 

[HoopsOnToast]

Well after a lunchtime round Andy's gave me a few more ideas.

With the FF225Ks slotted in to his OBs seemed to do very well, especially with the RAAL ribbon tweeters crossed @ 6kHz. On their own they sounded OK running up to around 12kHz where they start to drop off. I thought they sounded a little closed in in the treble without the RAAL's.



ADPully Hifi Visit by RSdesignUK, on Flickr



ADPully Hifi Visit by RSdesignUK, on Flickr

I think in the short term I will give the BiB cabinets a go, although I might get out today and knock some baffles up and 'whack'em'in' for a bit of fun!

Long term, I still think a full active OB setup is the way forward.

Thanks to Andy again!

 

[falcoron]

I agree finding a HF ribbon to fit your price spec is probably doomed from the startHow about using the Bastanis OB starter tweeter. I reckon is a Eminence APT50 it's a 105dB horn tweeter and it fits the bill on price.

http://www.ebay.co.uk/itm/Eminence-APT50-45W-Super-Tweeter-Screw-In-Tweeter-/130936288623?pt=UK_Sound_Vision_Speakers_Monitor&hash=item1e7c69356f

If you select this I do have a pair of wooden flares you can have for free.

I had the monocor ribbon tweeters for a while with my first open baffles and thought they were just ok, but the bastanis horn tweeters are day and night better.

if going active for the bass i can recomend the berhinger inuke amps with built in DSP crossover facility plug into your laptop and get the graphs so you can do the 6db boost and get the bass nice and deep to compensate for the narrow baffle, works a treat with mine.

 

[HoopsOnToast]

Well its been a productive morning, they do a lot better in the bass than I was expecting going by the low Qts.



Test Baffle #1 Fostex FF225K by RSdesignUK, on Flickr



Test Baffle #1 Fostex FF225K by RSdesignUK, on Flickr



Test Baffle #1 Fostex FF225K by RSdesignUK, on Flickr

 

[falcoron]

bigger the baffle = more bass

 

[HoopsOnToast]

:zip: no but my brothers old desk has a new lease of life....

 

[HoopsOnToast]

I had the monocor ribbon tweeters for a while with my first open baffles and thought they were just ok, but the bastanis horn tweeters are day and night better. if going active for the bass i can recomend the berhinger inuke amps with built in DSP crossover facility plug into your laptop and get the graphs so you can do the 6db boost and get the bass nice and deep to compensate for the narrow baffle, works a treat with mine.

Ron, just had a look at that Behringer iNuke amp, looks very flexible, been playing with the software and could not be easier!

Which model do you have? How do you find it in everyday use?

 

[paulf-2007]

The FT17 is what I use to deal with the roll off of the CSS FR125's I have, you remember those Rob. I think they do a nice job. Ok they are not Raals but you pays your money and takes your choice. Go on invest in some Raals and you will never need to buy tweeters again. I wouldn't part with mine no matter what speakers I might build in the future. There would always be a place for them with a recommended crossover of 1.6Khz.

Only problem with those are they are ~£100/ea, bit much really. The Fostex FT17 is quite cheap but read mixed reviews of its performance.Ideally I would like a ribbon but not too fussed at this moment in time.

 

[HoopsOnToast]

Cheers Paul, I found some Fountek JP2.0s going cheap which are on their way to me, as well as some free ones donated by Vinnie :^

The founteks are as close as I can get to RAALs for a good while!

 

[HoopsOnToast]

A brace of ribbons have arrived, the Fountek JP2.0 and some free Silver Flute/Dayton YAG20-1 (from Vinnie/Bonneville)



Fountek JP 2.0 Ribbon Tweeter by RSdesignUK, on Flickr



Fountek JP 2.0 Ribbon Tweeter by RSdesignUK, on Flickr



Fountek JP 2.0 Ribbon Tweeters by RSdesignUK, on Flickr



Ribbon Tweeters by RSdesignUK, on Flickr

Should be fun! (Ignore the marks round the Founteks, they had a sticker over the front)

 

[paulf-2007]

not a bad idea to keep those ribbons protected Rob, mine have cling film over them while boxed and right up until I fit them . Just constructing new bass open boxes with the Raal's mounted in same to reduce the height of the overall units. Top of 200Hz tractrix is still over 1m.

 

[HoopsOnToast]

Yeah they will go back in the box until I get them up and running. :^

 

[paulf-2007]

I took one of the Raal's from the box and tried it in the opening I was trimming and when I put it back in the box I had it round the wrong way and the two units stuck together by magnetism, I had a job prising them apart.

 

[LaSeR]

bigger the baffle = more bass

Bigger the baffle = uglier the speaker.