FX 120 enclosures for workhorses

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Greetings, all.
I am a true neophyte to the world of DIY audio. I have recently become interested in building a set of speakers for no other reason than to save money, and I thought that it would be a fairly simple undertaking. I can honestly say that I had no idea of the intensity, depth and breadth of the information I would encounter. At any rate, I wanted to present my ideas to the gurus here and get some feedback.

The speakers will be true workhorses. They will be part of our family A/V system, and will used for TV, DVDs, CDs, VHS, and even audio cassettes. Our music ranges from Mozart to bluegrass to Boston to Julie Andrews. They'll be attached to a JVC RX-558VBK receiver with a range of 40-20k MHz, and there's no subwoofer for the low ranges. They need to be floorstanding, and will be either against a wall or in a corner; however, their placement will have nothing to do with audio reproduction but will be decided by how my better half decides to arrange the room. They need to be simple to build, and total around $300. A wide field of sound would be nice, but I'm expecting to sacrifice that by going with the full-range drivers.

My first thought was to go with Echo MTM mini-towers from North Creek, but they're designed for use with a sub. After lots of web surfing and forum scouring, I am leaning toward Fostex FX120s in Fonken towers, although I'm wavering on BIBs. I also considered Zigmahorns, but the comments I read on the Fonkens swayed me (plus the Zigs were designed for 103s, not 120s). What I don't know is the difference between the original freestanders and the MkIIs (besides dimensions). The biggest mark against the BIBs is that they're...well...big :rolleyes:, and I'm not sure how well received they'd be by my better half.

Thoughts?

Mac
 
Mac - contact Dave @ Planet10 regarding the "Fonkenator"* enclosure for FX120.

He's made some changes to the aesthetics/form factor after the pair we built for Jim Rebman's F120As, and I actually haven't got around to building this design yet.

*freshly minted moniker
 
Are you sure you want to go with a full-range design for your primary (and only) sound system, that's going to be used by the whole family for everything from TV to Mozart? Those FX120s have a claimed frequency response down to 70 Hz, but, if you were worried about the Echo's needing a sub, I'd be even more worried about this plan.

The good thing is that you're probably going to want them as up against the wall as you can get them to squeeze out every last drop of room reinforcement. Even guys with huge BIBs still go with subs.

Here's my experience: I built a pair of BIBs with Fe126es that I still have and enjoy on a secondary basis. They don't go low, and they don't sound "right" with the TV. I have a pair of Jordan JX92s in a poor cabinet (my own fault) that sound OK. The treble is beamy. It doesn't make for a very good "ambient" speaker, and you cannot get enough bass out of them to enjoy Boston. I thought I was getting imaging, vocal "purity", blah blah blah blah.

I bought a pair of these off of Craigslist last night for $40:
http://users.ece.gatech.edu/~mleach/labsp/

Just about the unsexiest thing you've ever seen, right? 3 drivers in a monkey coffin. They hadn't been played in 8 years, since the student built them, and have spent their time as end tables.

They completely destroy the Jordans and Fostex's in every area you'd care to mention. Speed, soundstage depth and width, frequency range, smoothness, dispersion, vocal realism, hairs-standing-up factor, you name it. I sat my wife down in front of them and said, "See how it doesn't sound like it's coming from the speakers", and she said, "I was more noticing how it sounds like I'm sitting in front of an orchestra."

They didn't have to "break-in", they didn't have to have BSC applied (of course, they have an extensive crossover network), I didn't have to "get used to all the new sonic information I was now hearing", there was no need to futz with where my head was in the room with regard to bass nulls and the toe-in of the speaker - they just sounded beautiful, everywhere, from the first second they played.

My point is, I've had fun with the fullrange drivers, and I still want to make some different cabinets for the 126e's. However, for primary speakers, where you want to be able to enjoy a decent frequency response and good dispersion, I'd be looking at some 2 way kits or designs (3 ways are probably out of your budget), from ZaphAudio, Parts Express, or Madisound.

Just my uninformed and unsought opinion, of course, but I thought I'd offer my heretical views. ;) I have no direct experience with the FX120s.
 
If they're going to be family workhorses & you need useful output to 40Hz, you need bigger speakers. A little 'un isn't going to cut it on heavier stuff unless supported by a sub. As you say you have no control over placement, reasonably wide dispersion will probably be necessary (not something larger FR drivers really excel at), so I suggest you take a look at one of Zaph's designs, like his BAMTM in the floorstanding form. http://www.zaphaudio.com/BAMTM.html
 
Further thoughts?


If you still want to stay in the Fostex family, the FE167E in either a simple MLTL a la Bob Brines or one of Dave's custom Fonken series floorstanders (warning - not the easiest build) , or FF165K in something like the Abby.

Any of the above will certainly have quite an advantage over the FX120 or F120A in terms of sensitivity/dynamics, and low end extension, but perhaps at the premium of low level inner detail.

Of course, optimum performance from the larger drivers will require bigger boxes.
 
I have uses 167's all around for my HT for quite a while now. I have the fronts in MLTL's and the surrounds in up-firing BR's. For normal usage which is a lot of music and TV, I set the fronts to large and cross a single sub in at 40Hz. For action DVD's, I'll set the mains to small and bring in the sub at 80Hz. The latter would probably be a good setup for heavy metal, etc. No I don't have a center. More problems than it is worth.

Bob
 
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The FX120 in the Fonkenator (another of Chris' stellar working titles -- when we finish getting this design right will be FonkenFX), 1st was the Fonken-steen -- it works well, but it seemed a bit awkward aesthetically, and also told us we could probably go lower, and larger -- enuff to reach the floor. It may end up being a touch big, but it should hit the 40s -- this one is about exploring the limits. With its "monster" 5" cone it is not going to be happy trying to play really loud.

The suggestion of the FE167 is too my mind a good one. More efficient, will move more air, with greater dynamics, but it won't reach as far down in terms of detail. But it does top & mid better than the bigger drivers. Fully treated they don't seem to suffer much from limited sweet spot.

If one wanted both, i'd put FX120 in a suitably sized sealed box, add a push-push pair of woofers under each one, perhaps CSS Trio8, and biamp. The downside is that the budget is now soring.

BTW: Fonkenator is larger than Fonken167 and trickier to build.

dave
 
I appreciate all of your feedback. ilewis, I'm not sure about anything...that's why I started the thread. ;) I'm glad I did, since I think I was barking up the wrong tree.

Bob, it is your website that firmed up a full range solution in my mind. You make some strong arguments, and I like your KISS philosophy. Apart from any sound quality considerations, the two reasons that I favor a single driver are bang for the buck and simplicity. I don't have to buy or build a crossover; that means more $$ for the drivers and big points in the "simple" category. I had not considered the larger drivers, but after reading all of the replies, I'm definitely interested.

I know that I seemed to indicate otherwise, but nice, full bass is not one of my priorities. My current "system" has zero bass, so any of these setups - even the "little 'uns" - will be a major improvement. However, the comments regarding depth and breadth of soundstage are bothersome. Using the 167s in your HT fronts, how important are speaker placement and seating position to the sound?

And FWIW - it seems to me that if an enclosure design is "a bit awkward aesthetically," then "Fonken-steen" is a rather appropriate name.

Mac
 
Well Mac, I guess "awkwardness" is as subjective as anything else in audio - here's a link to a post with photos of the Fonkensteen

http://www.diyaudio.com/forums/showthread.php?postid=1589340#post1589340


This gorgeously built driver is not much larger than the FE126/7, but wants a disproportionately larger box when using Dave's resistive port tuning Fonken topology.

A subsequent design revision (my whimsically nick-named "Fonkenator") juggles some of the the dimensions to achieve a floorstanding configuration, that feels better on paper (but no yet built)
 
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Joined 2001
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mcgaugheyc said:
And FWIW - it seems to me that if an enclosure design is "a bit awkward aesthetically," then "Fonken-steen" is a rather appropriate name.

The name did indeed come about as their visual impact started to become clear as they were built... the end user loves them both sonically and aesthetically (a stand built od a sub with 2 Trio8 or maybe SDX10s would bring a sense of proportion back).

fonken-steen-1st-pic.jpg


the next build takes a lot from the Fonken167 in terms of form factor.

Fonken167-walnut.jpg


dave
 
Well Mac, I guess "awkwardness" is as subjective as anything else in audio - here's a link to a post with photos of the Fonkensteen

New Fonken pair is born. - Page 18 - diyAudio


This gorgeously built driver is not much larger than the FE126/7, but wants a disproportionately larger box when using Dave's resistive port tuning Fonken topology.

A subsequent design revision (my whimsically nick-named "Fonkenator") juggles some of the the dimensions to achieve a floorstanding configuration, that feels better on paper (but no yet built)

Firstly, I hope I am not taking this thread offtrack. If so, please let me know. I have recently purchased a pair of FX120 drivers, and am also trying to find out which cabinet design I should go for. Then, I came across this thread, so I thought I will add my own questions.

I am also a complete newbie at DIY, and am leaning towards a simple design. A simple design that I have found is the bass reflex cabinet as specified in DiyAudioProjects - a small 10 liter cabinet with a 50mm or ~2" wide and 80mm or 3.14" long port.

On the other hand, the Lautsprechershop website gives a different specification of 12.4 liter bass reflex cabinet and with a HP50 reflex tube, 7 cm or 2.75" long port.

Would anyone be able to give any advice on:
1. Which dimension is correct - 10 liter or 12.4 liter? I understand that this is further complicated by the fact that the actual driver parameters will likely be different from the stated ones. However, the two numbers seem to be significantly different for the factory ratings. Or, can someone please give some pointers on how this can be calculated?

2. How will this simple bass reflex design perform in the bass department (within the given constraints of this being a smallish 5" driver with a 2mm xmax), both in terms of SPL levels and reasonable accuracy?
Will it make any difference if I overbrace the cabinet or use thick marine ply - more than 1 inch thick?

Chris and Dave, would you be able to share any details about the Fonkenator and the Fonkensteen as well? I really like your Fonken designs, and although this may be too complex for me to build in my DIY infancy stage, I would be really interested in some details.

Thanks,
Arun
 
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Paid Member
I'd be happy to have someone beta test the Fonkenator (not for the faint of heart). Fonken-steen plans available by request. I also have a dFonkenFX (10 litre) and am going to see if i can rework the FonkenPrime (13 litre) for the FX now that the only FE127 available (other than those in people's closets) are what i have left.

Based on experience so far, FX should work in BR from 10-28 litre (the last the base of the Fonkenator, and a test of the limit of how big can be utilized).

I'm not a big fan of traditional BR, even just changing the port to a high aspect ratio slot really helps.

dave
 
I'd be happy to have someone beta test the Fonkenator (not for the faint of heart). Fonken-steen plans available by request. I also have a dFonkenFX (10 litre) and am going to see if i can rework the FonkenPrime (13 litre) for the FX now that the only FE127 available (other than those in people's closets) are what i have left.

Based on experience so far, FX should work in BR from 10-28 litre (the last the base of the Fonkenator, and a test of the limit of how big can be utilized).

I'm not a big fan of traditional BR, even just changing the port to a high aspect ratio slot really helps.

dave

Dave, how can I get some information about the dFonkenFX, especially the 10 liter version? Should I send you an email? This is exactly the size I am looking at, and I know that Fonkens are a more complex design, but I would really like to try it out, and considering the small size, I should be able to handle it if I work and plan carefully.

Thanks,
Arun
 
I had a pair of FX 120 playing the other day, amazing small drivers; forgot how well they image.
Pic - one set out of three FX 120 builds, I found it to be the best out of the lot, and felt they have good balance and great bass vs. size of box.

[The FX 120 has very good bass/low end, even in the smallish sized boxes]

Gesh... I see there is a price jump for the driver - 44%
 

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I guess I'm one of those who can accept the native sonics of most Fostex drivers as they are, and for my own use would only "filter" them with a line level HP to allow for bi-amping. Of course that raises the question - " OK, what's the 'best' woofer and XO point to use?" - for which there is no simple answer.
 
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