The Little Engine that couldn't

[Bare]

just finished or at least stopped with the 'break in ' of my CHp 70.2 drivers 120~ hours at lowish levels via radio.
Differences? None.. that I can discern.
Photo attached of these temporarily installed into Thrift store Sony boxes
Also of one the 40 year old, locally made non descript 8' full rangers that I've kept since new... simply because it/these worked a helluvalot better than a pair of Dynaco A25's I briefly owned.

Had Kids over visiting so I arm twisted them into auditioning the MA's.
Two of these young men are musicians whose 'band' regularly appears on CBC radio and television. Likely familiar I thought they could listen with some skill.
Resultant impressions ranged from: Ewww .. to: I hope you didn't pay much.
Pretty well echoing my observations, albeit far more bluntly though.
Tinny sounding and frequency constrained.. clearly outclassed by an 8" whizzer cone ..Geez.
Which also works a .whole world better than the wee MA gizmo in it's junkyard enclosure.
Hey! Not compared to Tannoys in GRF's enclosures ..this time.
This is a crabapples to apples comparison. Real world Fair IMO.
.
Maybe it's down to the crappy box. Not convinced on that one though
So what gives? Crap product? Spiked Kool Aid ? Or simply Emporer's new clothes?

I've seen a lot of Audio systems.. many clients request bespoke AV setups in their megabuck mansions.
Typically well north of $250K.
As result I've seen /heard /signed off on more Primo (claimed) Audio setups that most get to see let alone hear.
Have learned, through osmosis what is good and what isn't.
Lots of the Mega $ stuff is Sketchy. (B&W Snails for sure
However the truly good equipment is jaw dropping good.
I'm begining to suspect/realise that these miniature full ranger adventures are decidedly in the Shallow end of the Hi End pool, producing just enough hint of goodness to keep 'em trying.
Hell, even Lowthers have perennially proven iffy, far more often than not... not new ground.
An interesting distraction, for a while ..I think it's over now though.
Thanks for the help.

 

[picowallspeaker]

Nice approach to the science of music reproduction

 

[vinylkid58]

Maybe it's down to the crappy box.

I'm guessing it's too small.

So what gives? Crap product? Spiked Kool Aid ? Or simply Emporer's new clothes?

You do realize the CHP-70.2 was designed to have a rolled off treble, starting at 7kHz? This is the only MA driver that has this feature "built in" on purpose AFAK.

jeff

 

[Richard Ellis]

Just what did you expect? Common sense tells us a four inch driver won't accomplish much. There are legions of Full-Range fans listening right now, this very second as you read this......Of their 4" drivers marveling in the nuances of vocals & the violin.....alto sax, and many more. When these enthusiasts walk away from their systems to "I'm going to the store, be right back!".........In walks teenage son & sneaks his latest CD into Dads "Super fullrange" system & cranks the volume up.......the poor little Four inch driver starts hammering against the "stops"........Teenager gets look of horror......thinking he has broken dads primo set-up.
"What a piece of junk" son says to himself

_____________________________________________________Rick.........

 

[vinylkid58]

Just what did you expect?

He stuck a new driver in a box that was designed for something completely different, and expected it to sound stunning.

jeff

 

[kevinkr]

It does need a fair shake in a box actually designed for it. Might still not be your cup of tea, the FR thing so far hasn't proven to be mine...

 

[Melo theory]

I would understand if that was a sealed enclosure to test the driver but it's a reflex. The alignment could be way off.
Try and model the driver and see if you can mess with the port length and report back. Also if it sounds extremely tinny, maybe they are wired out of phase?

 

[pinkmouse]

Might still not be your cup of tea, the FR thing so far hasn't proven to be mine...

Same here, I've played around with a FR125 recently, and though it sounds pleasant enough, it just doesn't do scale, dynamics and imaging like a good three way.

 

[fakeout]

I can't remember exactly but I think it was something like treols graven web site but anyway, I read with some drivers, if you don't get the cabinet right, they could sound totally "off".

I like my Creative T12 speakers which have tiny full range drivers. I know people who prefer to listen with subwoofers would freak if they heard my speakers. I'm still amazed by the voice quality.

That being said, I sometimes crave more bass. So, my research is leaning lately more towards woofer/tweeter combinations. (I'm somewhat hesitant with 3-way and woofer/full range combinations.)

 

[kevinkr]

DIY Loudspeaker Projects Troels Gravesen

One of the best speaker sites on the web IMHO.
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm

 

[Cal Weldon]

CHp 70.2 drivers

If these have any comparison to the CSS EL 70 then I can tell you the box is a huge factor here. I get the giggles when I listen to the EL 70's in the FH Mk III box. They are a little rolled off on the top end but listenable. The giggle part happens when you look for the auxiliary woofer and find there isn't one. They have no business delivering the bass they do. I'm kinda with the others on the box. That doesn't look like it would sound any better than you are describing.

Notice: The above statement is coming from a confirmed big speaker guy so I am a little biased against these little drivers.

 

[kevinkr]

Same here, I've played around with a FR125 recently, and though it sounds pleasant enough, it just doesn't do scale, dynamics and imaging like a good three way.

I've been thinking that if I try another FR project I'd probably go with the Tang Band W8 - 1772.. My point of reference is a 3 way Ultraflex/Onken system with horns on top. I don't expect the same sense of scale, but an FR system with some sense of immediacy and a good bottom end could find a home here as an auxiliary.

 

[Pano]

I'd go with the Seas Prestige FA22RCZ instead. Unless you just like the eye candy of the T.B.

 

[mikejennens]

I think by randomly putting a driver in a random box, you do it injustice by judging it. I have a pair in a box designed for the CHP-70 speakers and I'm extremely impressed. I have other speakers that are quite a bit more expensive and complex. I might not be an "expert," but I've been listening long enough to know what sounds crappy to me. The CHP-70s in the right enclosure don't. I'd say the enclosure has as much to do with sound quality as the driver. Build the right box and then give it a listen. I'd be willing to bet you'll notice a world of difference!!!
Mike

 

[ODougbo]

Agreed Mike,

Here a pic of just of a few of the boxes I made for the 125wk. The bottom right looks like the one in the OP and is a "Fostex box".

There is night & day difference to the top pair (vs. BR box) I'm getting bass suitable for the 1812 Overture (volley of cannon fire). The mid range and imaging is darn right terrific.

 

[Scottmoose]

If you're expecting dynamic range equivalent to a multiway with larger drivers, then you're in the wrong place, especially if you've just stuffed them into any old box you had lying around without regard for what they actually need. There are certain laws of physics that apply. The box indicated appears far too small for them, no word on what it's tuned to, and the walls look rather close to the edges of the driver, which can cause early reflections back through the cone & frequently results in a more or less irritating 'cupped hands' effect.

Standard max-flat vented for the CHP70.2 is 10.87 litres tuned to 57Hz. Keele's alternate 4th order is 10.8 litres tuned to 54.8Hz. I wouldn't necessarily recommend flat in practice, but if a box was built to the Keele volume, the amount taken up by driver & vent should drop Vb to about 10 litres & give a slightly more damped output.

As noted, the CHP70.2 has the top end considerably shelved down -this is clearly stated in the data sheet & visible on the FR chart. Some like this, & find it useful for relaxed listening, some don't. I find them quite useful as small wideband midbass units.

 

[ODougbo]

Couldn't agree with you more, I believe the walls should "peal" away (angle back) if the box volume is large enough to make this possible.

Not as much with the top and bottom panels, they are too far apart - typically .

.............. and the walls look rather close to the edges of the driver, which can cause early reflections back through the cone & frequently results in a more or less irritating 'cupped hands' effect.

 

[thunk303]

Could you try blocking the port and stuffing the box with some fiberglass? Just until you get some better boxes built.

 

[Scottmoose]

It might make the box alignment marginally better. In the same way that some parts of the Titanic are marginally less underwater than others.

8 litres sealed will work; give a Qtc lurking in the 0.65 - 0.66 region, although that will vary depending on the output impedance of the amplifier. Not much LF gain, but then, you wouldn't expect any: it'd be a 4in wideband driver in a relatively low Q box.

 

[DYNABLASTERTUNERS]

for example a proper enclosure for chp70

Point Seventy Donhighend Audio
Die "Point Seventy" - Kleiner BR Lautsprecher mit dem CHP70 - Seite 4 - DIY-HIFI-Forum