Help designing EPOS clone

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Hello all,
I have theorized about my best 2 options for a while. So I am going to try both out.
The first design is an EPOS M12 clone using a 5 1/4" dia Tang-Band polycone driver running full range ie - rolling off naturally in the LF and HF. Here is the link:

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-850&CFID=2395018&CFTOKEN=28055281


I would then add a 1" tweeter with a cap to roll off LF under 12 k
My questions for assistance are:
1) Should I use Parts Express .25 or .375 cubic ft cabinet.
2) What do I use for x-over on the tweeter? 1st order to roll off LF under 12k.
3) What tweeter do you recommend? I don't think I'll like the sound of a piezo tweeter and don't think I should go under 1" because I think this will best match dispersion of 5 1/4" woofer. I.E. it will beam over 10k and off axis dispersion should compensate for reduced output over 5K of the woofer.

I don't mind beaming as I listen no more than 5 degrees off-axis and beaming should eliminate room reflection problems.

My second design is simply the FR-125.

1) Should I use .25 or .375 cubic foot cabinet? To reduce the well-known bass bump I would like to tune a little lower than recommended - around 55 hz I'm thinking. I was told tuning below the normal 65hz will reduce the overall bass output and, in my case, the unwanted boost to bass at around 100hz.

Thanks for help. I would like to order the parts tommorrow.
 
which epos

are you wanting to clone? Have you heard them in the context of your system?

Regardless, the TBs were not the drivers they used in any of their speakers as far as I know.

what application, what equipment, how big of room, what are musical tastes?

What's your budget?

Once you have realistically answered these questions, much help will "appear". Without it's like fishin for a Great White Shark in Lake Tonkawonka :scratch1:
 
Hi Nanook,

which epos Post #2 are you wanting to clone?

- As I mentioned Epos M12. But getting rid of the nasality and cabinet resonances at 450hz would be a plus :)

Have you heard them in the context of your system?

Heard them with Creek, Rega, and M-F amplification. Pretty consistent qualities from system to system and I like the transparent, musical, not-hyped, rythmic sound they produce. I don't listen over 80-85 db and Epos don't play loud but that's okay for me.

Regardless, the TBs were not the drivers they used in any of their speakers as far as I know.

- You are correct but this driver seems to come closest to the Epos p-p cone, albeit a little smaller. Specs from Parts-Express looked pretty good. Did you check them out? What do you think?

what application, what equipment, how big of room, what are musical tastes?

- Musical playback
- Vecteur I-4, Marantz CDR-500
- 13 x 15 feet and highly reflective.
- Rhythm and melody. I listen to the Police, Everclear, Fluke, Curve, and the way my TB W3-871s blend all the instruments, without ear fatigue, in a nautural manner, with great rhthym, I feel like I'm hearing the musical truth. While I like rock music , don't follow the tradition of LOUD and BASS most folks seem to link to the genre.

What's your budget?

Well, I can do the FR-125 for <$300 so say $500 max.

Don't know if you want the long version. Would like to go full range single driver but not sure if it's pratical. Hence the comparison the the FR-125. I have decided against metal cones although I wish I could hear the Jordan's. Don't want bright, fatiguing or resonance of metal.
I like the snappy detailed sound of paper and seems a good match for low listening levels. Unfortunately Fostex FX120 seems to be a bad design and bass said to lag. Perhaps the relatively large paper cone flexs. Concerned about the roughness in the HF of the FR-125 and the boost in the bass.
In general I dont like p-p cones because of poor internal damping and p-p "eats detail". However I don't seem to hear this with Epos and also the $$$ Skaaning drivers. Hence the Epos clone.
Also speakers like Bob Brines F200 design are rough in the H-F and don't produce much sound below, I'm estimating 70dB. Then all of a sudden they wake up.
Figuring I may have to go with 2 way and if so, NO x-over components on the woofer, would like woofer running full range as the more you limit a driver in it's FREQUENCY range, the more you limit it in the TIME domain - hence poor rhythm.
 
not sure if this helps much..(planet 10 where are u?)

But were the M12s broken in? Seems like this is an issue with these speakes, and they have recieved a fair bit of positive press. Seems like some could be had "on sale" near your price range.

As for sreten's suggestions, it seems that whatever Zaph touches turns to gold, and his designs have been well recieved.

My suggestion concerning NorthCreek speakers is that they are similarly sized, and currently on sale , well within your budget, use good drivers, and have been out there for some time.

As far as single full range drivers go, I'm not sure what drivers would work well in a .25 ft^3 box, Dave help me out..but a pair of his Fonkens may be an answer if a full ranger is desired.

So many choices, it'd drive me nuts to be shopping for a DIY project/kit/speakers at all (but if space permits, come on over to dark side....er I mean Open Baffles) :devilr:
 
Thanks for the info. The Zaph design looks really good. I was hoping for no x-over on the woofer to maximize transparency. I think it will measure better than the Epos design but not sure in actual listening.

"So many choices, it'd drive me nuts to be shopping for a DIY project/kit/speakers at all

Ain't that the truth!
 
chuck55 said:

I was hoping for no x-over on the woofer to maximize transparency.

Hi,

This was a feature of Mordaunt-Short and Epos designs due mainly
to the influence of the designer Robin Marshall. The technique requires
careful profiling of the cone to influence the response and is arguably
only partly successful.

(And certainly not applied to the TB 5" unit)

Manipulation to the extent of providing full baffle step compensation
is not possible (easily fixed with line level BSC), most of the c/o less
on bass units speakers require near wall enforcement of the bass.

Transparency wise the mid/bass units are being manipulated to begin
breaking up lower than they would normally and higher modes are
difficult to control, though I'm not knocking the principle, can work.

Zaph's design is complete, all the hard work is done, and its not
based on opinions and conjecture, but hard measured facts, the
drivers are selected on what they do, not what they might do.

IMO no-one who really doesn't know what they are doing is going
to build anything remotely as good using a wishful methodology.

(I've nothing against full range drivers, correctly equalised)

:)/sreten.

edit : a full range FR-125 or two way WR-125 after equalisation
has very low efficiency (but lots of excursion) so plenty of juice
would be required.
 
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M12.2 is nice, though a bit nasal. But this can be cured by using thin wall & bituminus damping construction. Yes I prefer your approach using the TB p-p. I would compliment it with a Vifa XT19.
You should have access to basic measuring equipment so to succeed with the single cap crossover.
 
Salas, I was looking at the Tang-Band 28-847SA - same company maybe voiced the same. Anyhow Parts Express sells both so it was easier this way. All the stuff should be here Thursday.

Sreten, your logic is convincing. Zaph uses the same .25 cu ft box and I ordered extra baffles so it will be a simple matter to get the drivers from Madisound and try it out.
Do I need a circuit board? Will have to read Zaph's article more closely.

I guess I now have 3 designs to compare. Will let you know my impressions.
 
Results are in first the FR-125:
Initially they sounded weird tonally. Also pretty flat and little bass. After about 1/2 hour I think the tonality was okay and the bass came on in a BIG way. Soundwise, it's a fun speaker, a party speaker.
In fact, that's all I heard, bass. Reminded me of Dynaudio Audience 40 (or 42's) with Musical Fidelity X-150 amp. Or if you like Paradigm then maybe this is a good speaker for you.
It's too bad they made this driver with overblown bass and the esultant lower efficiency, While they can play loud they is some life and low level detail that gets blotted out. For example in Stevie Ray Vaughn's "Couldn't stand the weather they three pauses have quiet tapping counting the beats and they are virtually inaudible unless I turn up the volume above my normal level of 70-80dB. Also the "downward" sound profile doesn't help.
I tried tuning the .25 cu ft cabinet to 39hz and 50hz hoping to lower the bass. Didn't really work. Stuffing the vents made the sound constipated and lifeless although bas levle was reduced. I also tried eq'ing with a cut to the bass and boost the hf but just didn't sound correct. So in conclusion, it is what is is and trying to make something differfent out of this driver gives questionable improvements IMHO.
 
The Tang-Band W5-704 - ran these full-range with no tweeter for simplicity.
I liked this driver right out of the box. They sounded "right" to me. However after 15 minutes what seemed to be higher resolution than the FR-125 was as much HF harshness as detail.
Unlike the Fostex F200 p-p cone which I thought was rough, the T-B running full range was harsh. P-p cones have worse internal damping than paper so maybe this is why. While they were pretty good under 70dB, they got unpleasant above that.
Funny how they rolled off over 13k but I wasn't really bothered by the lack of "air".
Maybe this is why this driver would need to be x-over below 4k and why the Epos M12 cone is profiled to roll off over 5kHz.

Stupid as this seems, I'll just stick with my little T-B 871s since nothing so far has bettered it.

BTW, I tried out that Sonic Impact T- amp. What a p-o-s. Even on battery power and paper driver speakers; hurt my ears, harsh, vocals didn't sound like people. Okay for $35 it's great but any Aiwa DINA amp would beat it as did my Denon M31 mini. No way would I go any further with the "T" or digital amp stuff as compared to the chip amp which is an incredible value to my ears. Lacks the drive of my Vecteur I4 but other than that. . . nice amp.
 
In case anyone is still following this thread:

I tried the W4-616s full range in the .25 cu ft box. Just like Parts-Express said, nasty audible cone breakup modes at 6 and 12kHz. Reduced cabinet size to ~.15 cu ft and bass boosted to more reasonable levels so sound is more balanced. Still, the resonances remain.

Is it possible to eliminate the cone breakup modes? I saw a post where the poly-cone T-B cone was slit and filled in with rubber-like glue.

I love full range but don't see anything working like my little 871's, bummer.
 
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