Decision 2008

The plaintive cry of the n00b, I need help.

There are to many designs out there and my head is starting to hurt. I need help deciding what to build.

I've attached a rough layout of the listening room. It's 12'-8" x 10'-8" x 8'. The amp is a Jolida 202a (Gonna try wiring it triode.)

I really want to fit a Half-Chang in there. A B20 would fit my budget alot better than an un-modified fostex right now but I could stretch it if arguments convince me to go that way. I can mod them later as my skills improve.

Music runs the gamit from Vivaldi to The White Stripes with long stops in Alt. Surf rock and Post Rock Instrumental. (Who comes up with these genres?) With some Jazz and old country(Think Marty Robins ect.)thrown in to taste.

Designs considered so far, Half-Chang, Zilla's 3 cu. ft. B20's, Demitri, Melvina, Brynn, Floorstanding Fonkens(maybe even the PAWO style fonken), PAWO, Harderrors FE-126 Horn, and the Frugalhorn.

Any and all comments are appreciated. Plus if there are any designs I haven't listed that would be good canidates, let me know.

Thanks to all.
 

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Well, given that your taste appears to primarily reside amongst the heavier side of things, and the room is a reasonable size, I'd be inclined to go with the 8in drivers. They sacrifice a bit of midrange magic to give better LF, so should be a good compromise. The B20 is a fine unit for the money by all accounts, & you can always upgrade to the FE207E when funds permit, so of the speakers you list, my choice would be Half Chang with the B20 & a pair of tweeters crossed in at ~5KHz.

Dimitri would be my next choice of those you list, with the 8in units. Won't sound as big in the LF, but certainly not small. You'd need to go straight to the more expensive units like the 207 or FR8c if you went for this approach though.

If you wanted smaller, the Frugel-horn or Ron's A126 would be my choice of the designs you list. Midrange will be to die for & they certainly go plenty low, but I'd want them supported with dedicated woofers. Small drivers have their limits -you can go loud, you can go low, but they can't shift a large quantity of air as well as dedicated bass units. There's no substitute for diaphram area in this respect -LF transient handling in particular will always be weaker with the smaller drivers (love them though I do).

Basic test I've recently developed. To know if a speaker will do well on rock, play Phil Collins's 'I Don't Care Anymore.' Drums should a) sound HUGE, b) be quicksilver-fast, and c) you should feel the weight of air smack into your chest. One or all of these missing? Not a good rock speaker.
 
Originally posted by planet10
A simila question was posed over here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=116109

That's the one that prompted me to start this one. I am after information on my specific situation.

I guess I should have titled it "Can I squeeze a Half-Chang in here?" :)

These will not be the last speakers I build. I forsee a long journey ahead. A journey that's filled with mistakes, dead ends and learning. I'm just trying to minimize the dead ends before I start so initial disappointment dosen't blunt my enthusiasum.

Yes. It is a pretty small room but it's MY room. I've been given free-reign over this room only and it will wear many hats. Listening room. My computer room(the rest of the house belongs to the Mrs. and her laptop.) Video game room and project room will be a few of it's duties. In other words, a total man cave.
 
gurley123

I think you'd very much love the Jolida in triode - if you haven't already researched it, you might want to try bypassing the feedback - the JD302 works very well that way.

Begging your pardon Scott, but all things considered, I'd tend to suggest maximum 6" driver for a room this size.

I think you can count on enough room gain that any of the full sized Scottmoose or BIB designs for 8" drivers would easily overpower the room, and if placed near the corners, might well have trouble integrating a seamless soundstage at the listening position shown on your sketch.


I recently built a pair of Brynns with FE127E for my sister, who is using them in a much larger room than you show (15'wide x 20'long, 15' cathedral ceiling, and extending into an attached kitchen/eating area) . She's only 2yrs younger than myself, so her headbanging days are past, and she hasn't yet complained about them not being big enough.
The Denon receiver she's driving them with however isn't as satisfying as the Kingrex T20U with which I first demo'ed them.

Back on topic;

If you're uncertain that 4" driver would work, and willing to try an as yet unproven design (I'll get around to a pair in the next couple of months) , contact Dave for drawings for a Half-Chili Chang for FE167.
 
Food for thought Chris.

I'm not a high volume listener really. Oh, I'll turn it up on occasion but not as a norm. Any guesses as at what dB overload will start to set in?

The B20's have multiple pro's for me. One is price. Next, it is that they are basis of another design I wanna build down the road. Also it doesn't seem to have a rising frequency response like the fostex. I am pretty sensitive to "bright" or "shouty" sounds from my hi-fi. My current speakers are a pair of early 90's KEF coda 9's with an internal 6 1/2" bandpass woofer(They weren't even listed in the history section of the KEF site last I checked.) I have to turn the wick up a good ways before I feel the room is getting in the way. This is with the Jolida in stock Ultraliner mode for 40 watts. Figure roughly half that triode, and I think I can keep the 8"ers outta trouble.

I am open to 4" with helper woofers. I have definate plans for a Frugalhorn. I was kinda holding off on that one till my skills matured a little. I wanna do it right. That includes getting some drivers from Dave which is cost-prohibitive right now.

At the moment, the Half Chang seems like the right one to cut my teeth on.

Slightly off topic, Chris, any links or info on taking out the NFB on my 202? My last google search didn't turn up much.

Keep the suggestions coming. This has been an enlightening forum for me over the last few months.
 
planet10 said:
Scott,

You must be from England or something. I'd put 10x12 into the smallish category,

Yep, we decadent Britishers again. An Englishman's hovel is his castle. :D

Re the driver size question, fair point -the 6 1/2in & smaller units will be easier to get singing right in a space that size. Still, 8in isn't impossible. Too much power? Damp 'er down or bleed off some pressure. I've had Ed's Vofos running in my room (roughly the same size), unmodified, no probs. Though my 167 MLTLs admittedly sound a little sweeter, if not quite as dynamic, so YMMV as always. ;)

Depends on the design, the driver, how loud & how far away (& the axis on which) you listen, as to when distortion becomes audible. People also tend to assume if you hit Xmax, the end of the world is neigh. Which is not so. Some drivers distort badly on breaching Xmax. Others (Fostex units are known for this) are relatively benign, with distortion increasing only gradually, the further past linear excursion you go. Also, given that this is primarily down in the LF, where our hearing is poor at best, within reason, it's not really that much of a problem, again, assuming you're not asking the impossible.

If you've got a driver in a cabinet where you have a degree of reactance anulling going on, then you have better control than other boxes, & they can go louder, cleaner. Ed claims very high SPLs are possible with his Horns, & I believe the Frugel-horn & Ron's A126 share this trait.
 
gurley123 said:
Food for thought Chris.

I'm not a high volume listener really. Oh, I'll turn it up on occasion but not as a norm. Any guesses as at what dB overload will start to set in?

The B20's have multiple pro's for me. One is price. Next, it is that they are basis of another design I wanna build down the road. Also it doesn't seem to have a rising frequency response like the fostex. I am pretty sensitive to "bright" or "shouty" sounds from my hi-fi. My current speakers are a pair of early 90's KEF coda 9's with an internal 6 1/2" bandpass woofer(They weren't even listed in the history section of the KEF site last I checked.) I have to turn the wick up a good ways before I feel the room is getting in the way. This is with the Jolida in stock Ultraliner mode for 40 watts. Figure roughly half that triode, and I think I can keep the 8"ers outta trouble.

I am open to 4" with helper woofers. I have definate plans for a Frugalhorn. I was kinda holding off on that one till my skills matured a little. I wanna do it right. That includes getting some drivers from Dave which is cost-prohibitive right now.

At the moment, the Half Chang seems like the right one to cut my teeth on.

Slightly off topic, Chris, any links or info on taking out the NFB on my 202? My last google search didn't turn up much.

Keep the suggestions coming. This has been an enlightening forum for me over the last few months.

No doubt a less than 8ft listening distance in a smallish room will exacerbate any shrill/shouty characteristics of any system.
While not a fan of the method myself ( I think you lose more than you gain), at least one way to tame the rising HF response of a FR speaker would be a contour network - I'm sure other methods could be suggested that don't require custom driver mods (although some of those definitely work).

With a 3 stage tube amp such as the Jolida, there's plenty of opportunity to mitigate many issues with tube rolling alone, before, without even "opening the hood".


For example, vintage pullout (read very well used) Mullard 12AX7 from a Dyna FM3 tuner I bought used for $70 creamed the stock chinese tubes that came in my 302, and Svetlana EL34 performed an equal level of transformation at the other end.

I'm sure the basic scheme of the 202 and 302 are similar enough that the feedback loop would be easy to identify, and in the case of the 302, it's a far easier mod than the triode conversion (i.e. it requires only the desoldering of 2 connections).

There is a wire running from the 8ohm speaker terminal to the feedback components (RC) near the input tube section of the PC board. In the case of the 302 those parts are labelled R2 and C2. In my own case, rather than completely removing that wire, I installed a DPST toggle switch to allow the feedback to be turned on /off (with the volume turned down of course).

I've used the amp this way sporadically* during the past 3 years, and aside from the obvious increase in gain and associated noise, I generally prefer the bloom on FR speaker systems without the feedback.

*sporadically, because with my small room, relatively efficient speakers and listening habits, raw horsepower isn't required, and either the EL84 ClassA P/P, or 2A3 monoblocks quite simply out-finesse the Jolida.


Scott:

Although FE126E would be capable of peaks of well over 110dB at the listening position in many BLH or BVR designs, not everyone needs that to enjoy their music
 
I've already rolled the tubes with positve results. The NFB bypass sounds very doable. Can't wait to try it out. I've had this thing since 92 or so. I guess it's time to tinker with it.

I would rather not put any more passive components in the signal path than strictly necessary. That's what drew me to full range designs.

With regards to driver mods, I've been lurking here long enough to pick up the rudimentary bits of it. In one post, Dave described some of the things he did to a pair of B20's and I took some notes. I'm pretty good with a brush so I'm willing to risk a $50 set of drivers to learn on. More expensive ones I'll leave to the experts. :)

Like I said. These will not be the last stop, It's just the first step. 4", 6 1/2", heck, even the FE 85k with help below will probably make an appearance at some point. Lotsa good stuff out there to try.
 
chrisb said:
Scott:

Although FE126E would be capable of peaks of well over 110dB at the listening position in many BLH or BVR designs, not everyone needs that to enjoy their music

I'm completely with you Chris. I value my hearing too much to crank music that loud. I was primarily refering to the headroom rather than the sustained or peak SPLs. Not essential of course, but nice to have.
 
gurley123 said:


<snip>

Like I said. These will not be the last stop, It's just the first step. 4", 6 1/2", heck, even the FE 85k with help below will probably make an appearance at some point. Lotsa good stuff out there to try.


EnABLed FF85K makes a surprising OB mid/tweeter good from about 150Hz on up - with a bit of tinkering, MJK's recent OB project could easily be adapted for this driver. The adventurous could even go active with PLLXO/digital XO etc to keep passives out of the speakers altogether.

so many experiments, so little time :headbash:
 
gurley123 said:
I've already rolled the tubes with positve results. The NFB bypass sounds very doable. Can't wait to try it out. I've had this thing since 92 or so. I guess it's time to tinker with it.


Triode wiring usually comes before feedback removal althou the NFB Pentodes might be interesting.

dave
 
planet10 said:


Triode wiring usually comes before feedback removal althou the NFB Pentodes might be interesting.

dave


Absolutely forgot that I only ran this thing in pentode for about the first 6months (now over 7 years old). The difference in max power output between the 2 isn't really substantial in terms of dB.

Without completely gutting the PCB and re-wiring PTP, or even wholesale swapping of passive components, the next biggest improvement can be made by replacing volume control and coupling caps (now if you really want to see some fur fly, ask "what's the best coupling cap?")


Scott: as for bass extension and articulation ( the former pointless without the latter in my opinion), I rather like Victor Wooten on "Flight of the Cosmic Hippo" - not technically "rock", but it certainly grooves.

Then there's BlueMan Group - I caught them on an HDNet concert last week, and the suspended bass drum and smashing piano on "Teenage Wasteland" is just too much fun to watch.

Not as ethereal or spiritual as Loreena, but damned entertaining nontheless.

oops, I digress