FH3, Pensil or Something Else?

st_eloi

Member
2008-04-29 9:45 pm
I built a pair of mFonkens many years ago, my first foray into diy hifi. I've been very happy with them, sometimes backed up with sealed 12" powered subwoofer, most for the past few years just the little speakers.

Recently I got the itch again, built a pair of Fonken Floorstanders MKII and was amazed at the bass the little FE127e drivers could produce. In the interest of experimentation, I picked up a pair of MarkAudio CHP-70.2 from Scott to try out. Swapping one driver in the floor standers and panning L/R the difference was immediate - as expected the top end was much less prominent. I had found the treble of the FE127e quite fatiguing so this isn't such a bad thing. Now I know the Fonken boxes are not designed for the MA drivers, but they did sound very boxy and constricted. The FE127e pushed the soundstage right out towards you, while the MA drivers are much less forward and engaging. I'm so used to the Fostex drivers I can't tell what's "better". The low end seems pretty even between the drivers, the Fostex maybe go a bit lower, but the CHPs aren't fully broken in yet, and the boxes aren't designed for them.

Now, my questions for the experts of the forum:

What driver / cabinet combo would produce something in between? I really miss the forward engaging presentation of the Fostex, but I don't miss the slightly harsh fatiguing high end. Can I have my cake and eat it, or is the in-your-face-treble the reason the Fostex present such a lively soundstage? Will the CHP-70.2 in their own box achieve this, or do I need to upgrade to Alpairs? FWIW I know the CHP-70.2 have reduced high end. Do the Aplairs have top end sparkle without the fatigue?

I'm considering either the Pensil or the FH3 with the CHP-70.2 to start wth. Then an upgrade path of Alpair 7 (7.3 / A if I can find them, it sounds like the latest MS version aren't going down that well). I can reduce the internal volume of the Pensil 70.3 to match the Alpair 7 box. The FH3 would just be fiddling with the stuffing I think.

It'll be good to have complete Fonken FS and the new MA based cabinets side by side to compare.

My room is about 4x4m with a 2.7m ceiling, but with a large kitchen and hall off to one side. Pretty "live" no curtains and only a rug in the middle. I've attached some photos to explain. I don't have a flat wall or corners to put the FH3 against, are the Pensils more forgiving of placement?

Amp: Charlize II
Preamp / Phono: TC-754
TT: Modified Thorens TD166 MKII with Linn Basik Plus & Audio Technical AT110


Is my TA2020 amp with ~12w PC underpowered for the MA drivers?

Background listening: Sonos / Spotify, no DAC or anything, just line out to the preamp (will the Alpairs show this up to sound awful?).

Music is anything from Paul Simon and Leonard Cohen to Led Zep, New Order, Johnny Cash, INXS and lots of current artists, Alabama Shakes, Kevin Morby... could go on forever. Basically mostly well recorded old stuff and well produced new stuff.

I do still have my 12" sub which I'm going to reinstate, but mainly for movie watching.

TL.DL - FH3 or Pensil, and will the MA drivers ever sound as sparkly and forward as the Fostex?

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Now I know the Fonken boxes are not designed for the MA drivers, but they did sound very boxy and constricted.

Natch. ;)

The FE127e pushed the soundstage right out towards you, while the MA drivers are much less forward and engaging.

That's because the response balance of the two drivers is very different; the old 127 had the classic Fostex rising response; the CHP was specifically designed with a shelved down top end.

I'm so used to the Fostex drivers I can't tell what's "better". The low end seems pretty even between the drivers, the Fostex maybe go a bit lower, but the CHPs aren't fully broken in yet, and the boxes aren't designed for them.

In practice the CHP will get at least as low, & typically be happier doing it, but you need to run them in a box that is actually designed for them. They'll (sort of) go in the Fonken floorstander, but the alignment wasn't designed for it, so it's unlikely to give of its best.

What driver / cabinet combo would produce something in between? I really miss the forward engaging presentation of the Fostex, but I don't miss the slightly harsh fatiguing high end. Can I have my cake and eat it, or is the in-your-face-treble the reason the Fostex present such a lively soundstage?

Correct. An enclosure primarily affects the low end. This can have a concomotant effect on the perceived balance, and (for example) an excess pressure can overload the moving components of a drive unit, affecting the mid & HF behaviour. The CHP tends to like acoustically large volumes if you want as much HF as it can give, but it is not going to have a subjectively 'forward' or 'projective' midrange / HF balance because it was designed to have a more laid back character.

Will the CHP-70.2 in their own box achieve this...

They'll do better in something designed for them (or akin) than in something designed for a different driver, with different response characteristics.

...or do I need to upgrade to Alpairs? FWIW I know the CHP-70.2 have reduced high end. Do the Aplairs have top end sparkle without the fatigue?

Your call re the former; yes re the latter (by general consensus).

I'm considering either the Pensil or the FH3 with the CHP-70.2 to start wth. Then an upgrade path of Alpair 7 (7.3 / A if I can find them, it sounds like the latest MS version aren't going down that well).

The MS units are selling fine as far as I know, although I believe a couple of people were disappointed the 7.3 was discontinued as it's been around for a while & is well known.

I can reduce the internal volume of the Pensil 70.3 to match the Alpair 7 box. The FH3 would just be fiddling with the stuffing I think.

More or less.

I don't have a flat wall or corners to put the FH3 against, are the Pensils more forgiving of placement?

If no boundaries are available, the pensil would likely be the better choice.

Is my TA2020 amp with ~12w PC underpowered for the MA drivers?

Possibly a little in a larger space; the Tripath also (as I recall) tends to be happier at lower outputs, although if you can give it the cleanest power supply you can, that should help.

FH3 or Pensil, and will the MA drivers ever sound as sparkly and forward as the Fostex?

The CHP won't, but as noted, it wasn't designed to. More the opposite. Not entirely, but heading more that direction than the character of that generation of Fostex units. You'll get more midband / HF clarity after a hundred hours of varied signal music; an acoustically large box will help a little; possibly a cleaner power supply to the Tripath (or a different amplifier) will also help somewhat.
 

st_eloi

Member
2008-04-29 9:45 pm
Great, thank you very much for your comprehensive response Scott. Looks like I should build the Pensil 7.3 and look out for some Alpairs in the classifieds. You don’t have a pair that need a home do you...? Would be great to demo them actually, but they’re such fragile objects it’s unlikely anyone would lend a pair.

Have you designed a Pensil for the Alpair 7MS?
 
Without humble bragging as to the number of my own builds, I’ll offer that I’ve found the versatility of the Pensils in terms of placement a huge advantage over the FHs in less than ideal rooms.
Yes, your CHPs definitely (intentionally) have a softer top end than most of the lineup - if you can’t find a pair of A7.3 on the previously driven market, I’d look at the Pluvia7.2HD.
 

st_eloi

Member
2008-04-29 9:45 pm
That's good to know Chris. I prefer the aesthetics of the Pensil too.

I'll actually be in Hong Kong in December, maybe I'll drop Mark an email and see if he has any dead stock. Either way, I'll build the Pensil 7.3 for the CHPs which I can then modify to take a Alpair drivers if I find them.

Thanks for the Pluvia 7 HD tip off, though I can't find a Pensil designed for it. As it's a replacement, are the parameters close enough to the Alpair 7.3 that it'll go in the same box?

--

Thanks for the 7MS Pensil Scott, didn't think to check the product info page. Unfortunately it needs a different box altogether so I can't modify a Pensil 7.3.
 
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The millSize miniOnken for the CHP-70.2 needs to be tuned lower then for the FE127. The wrong tunng wil create an excess of energy before roll-off and a higher LF cutoff.

The 5-ish litre milliSize box seems to be best with A6.2p (close to optimal volume). All the larger drivers tend to have a touch of “i’d really like a larger box”. The forwardness of the FE127 would disguise that.

dave
 

st_eloi

Member
2008-04-29 9:45 pm
Don’t worry, I’m not putting the CHPs into the mFonken boxes, I just tried them in the Fonken Floorstander MKII.

The mFonkens will remain untainted. For one thing the nice rebated baffles wouldn’t take a different driver.
 

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