Agreed, the manufacturer specifies sensitivity as defined at 1W of input power but we are not certain to what voltage does it translate to, so assuming it was meant for a 6 ohm load, then we have additionally good 1 dB more in this already. Secondly, it's said that the speaker is to be placed in open space away from walls which in another words means that full (?) bsc was planned into this design. We can boost sensitivity figure by reducing bsc to a degree more appropriate for placing it nearer to the room walls and there is the question of choosing the right 12" woofer driver so basically we have no sensitivity issues here, I suspect.
I was looking at this a few weeks back, man it looks good, niceee
Sure does look like a good contender which may draw attention of a larger group of audiophiles to consider it seriously. I like it also.
We'll have to wait until the replatform has been completed. The wiki is currently disabled (in an archive/read-only state).
I believe Jason is starting work on the move to the new platform but I do not know how long it will take.
Tony.
I had hoped someone else would launch the discussion of a spec for the $1k tower but it hasn't happened yet. Start below but obviously needs a lot more input before the design can harden with the choice of things like particular drivers.
OBJECTIVES
- Document design process in detail partly to inform but also to help the relatively inexperienced build close derivatives based on their own constraints such as difficulties obtaining specified parts locally.
- Make decisions based on maximising technical performance subject to balancing the constraints of budget, effort to build, acceptability in the living space, availability of parts,...
- Suitable for a first or second build by the relatively inexperienced.
- Reasonably acceptable in a shared living space.
- Total budget of around $1k.
TASKS
- Detailed reasoning that has lead the dominant design for this type of speaker becoming: 1" tweeter, 4-5" midrange, 2x8" woofer, bass reflex, tower.
- Target directivity? Tends to be wide bandwidth for this type of speaker. Shallow waveguide on tweeter? Tweeter with waveguide or separate waveguide?
- Constant width baffle or narrowing around the midrange and tweeter?
- Passive crossover? Still a requirement for this type of speaker?
- Cabinet material and design. Single enclosure. Separate isolated woofer and midrange/tweeter enclosures. Outer woofer enclosure with internal midrange enclosure.
- Soft or stiff mounting of midrange driver and/or midrange enclosure?
- Which brands with suitable drivers are widely available outside the US and Europe?
- How/where to work on a design given the diyaudio wiki is not currently considered usable? I tested it by fixing a typo and that seemed to work and so this perhaps need investigating more?
- What features are considered buildable and which are not given the tools and capabilities of a new or relatively inexperienced speaker DIYer?
OBJECTIVES
- Document design process in detail partly to inform but also to help the relatively inexperienced build close derivatives based on their own constraints such as difficulties obtaining specified parts locally.
- Make decisions based on maximising technical performance subject to balancing the constraints of budget, effort to build, acceptability in the living space, availability of parts,...
- Suitable for a first or second build by the relatively inexperienced.
- Reasonably acceptable in a shared living space.
- Total budget of around $1k.
TASKS
- Detailed reasoning that has lead the dominant design for this type of speaker becoming: 1" tweeter, 4-5" midrange, 2x8" woofer, bass reflex, tower.
- Target directivity? Tends to be wide bandwidth for this type of speaker. Shallow waveguide on tweeter? Tweeter with waveguide or separate waveguide?
- Constant width baffle or narrowing around the midrange and tweeter?
- Passive crossover? Still a requirement for this type of speaker?
- Cabinet material and design. Single enclosure. Separate isolated woofer and midrange/tweeter enclosures. Outer woofer enclosure with internal midrange enclosure.
- Soft or stiff mounting of midrange driver and/or midrange enclosure?
- Which brands with suitable drivers are widely available outside the US and Europe?
- How/where to work on a design given the diyaudio wiki is not currently considered usable? I tested it by fixing a typo and that seemed to work and so this perhaps need investigating more?
- What features are considered buildable and which are not given the tools and capabilities of a new or relatively inexperienced speaker DIYer?
I have successfully fixed a small typo. There are other recent edits. It seems to be usable at the moment but is that going to change in the near future? It would be a pity to start the documentation somewhere else because there would be inertia to remain.
It is inspired by Basszilla, the first version of Basszilla was a WAW (or FAST) system, a 15" woofer + Fullrange, in next versions mr.Dick Olsher added a tweeter to the design but stick with the fullrange, I m not sure of the XO points but one guess is that some Fullrange drivers lack the very highs (Like in my case w a scanspeak 10f) and instead of switching to a mid range he just kept the FR probably because of it's sonic signature, I read that he went through different tweeters until he picked one that he liked the way it sounded, probably applies to using Fostex as midrange too, I m sure Dave has better input on this.
Very well done, Thanks, I ll wait for more experienced guys to comment on this.
The appealing part of Basszilla is the open baffle, and what needed fixing was the ported woofer, so I kept showing you sealed-bass Orion-like layouts!
One last temptation from me: Alón Phalanx
Alón Phalanx/Poseidon Loudspeaker System (Ultimate Audio)
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Granted I only have listened to the basszilla a couple of times, but I would say it was the entire speaker that sucked not just the ported woofer.
Interesting, I was under the impression that Jason had completely disabled it. It is odd that it is allowing edits. I wouldn't trust it!
Tony.
Is this for one box, or for a stereo pair?
Active filters and multi amping is a good thing, and it does remove quite a few constraints on the design of a speaker. However, going active does add a bit of complexity to the audio chain, and the "typical novice" we are targeting with our design may not be into active filters and multi amps (yet). There were numerous mentions of "weak amps" (ACA, tube amps, etc.), and this does not sound like active filter + multi amp territory to me. My conclusion is that the speaker must have a conventional passive crossover.
However, an option for going active would be great (and it would be even greater if the filter functions were simple enough to do it with purely analog circuitry).
The idea is that the speaker will be on the lower bound in terms of cost for a "proper" high fidelity speaker. That is, one that can cleanly handle the transients in music at standard listening levels in a reasonably sized room in the home. Obviously for this to be realised the room response will need controlling but that is outside the project. This needs adding to the objectives.
The budget of $1k (US prices) is for a pair. The speaker will use good standard range drivers rather than prestige drivers and keep them within their comfortable operating range in order to avoid significant distortions. I expect this can be done within the budget but if not avoiding distortion takes precedence over budget. Outside the US the cost of the speakers will likely be significantly higher and vary from region to region so the budget cannot be a firm parameter. $750 (US prices) would be good since it will bring the cost below $1k in many others parts of the world.
I would agree that a passive crossover is likely to be a requirement but it comes at a cost in terms of performance, limiting the choice of parts and configurations particularly the midrange driver and increased price for those that already have the necessary hardware attached to other speakers. So it is a question that needs asking even if the answer can be anticipated.
As stated in the objectives this is a high fidelity speaker and so I can see no case to support "high end" components elsewhere in the chain. With a passive crossover it will require a high fidelity amplifier that can deliver 100-200W or so into the load of a typical "4 ohm" speaker. Achievable by pretty much all competent stereo amplifiers these days that haven't cut too many corners to reduce price (e.g. some cheaper AV receivers).
These points need adding to the spec as well.
PS I have checked the US price of an initial guess at a set of drivers and it was around $500. Add the cost of crossovers, wood, ports, posts and other bits and bobs and $750 US price does not look wildly optimistic as a budget. However, changes from getting things to work well together are likely to push costs up.
Here are few more thoughts on the Monkey Coffin. Comments please!
POINTS OF DEPARTURE (as I see them):
- The poll says it should be a three way, and it's okay to cost more than $500 per box.
- There were a few mentions that the speaker should work fine with "weak amplifiers" (AmpCampAmp, small tube amps).
- The speaker should be straight forward to make for DIY novices (we don't want to scare them, we want them to run to the hardware shop and build stuff on their kitchen table). There is no point in designing for expert builders, because they will design their own speakers anyway.
- Quite a few members seem to drool over the Yamaha NS-5000 type of speaker ("monkey coffin" / studio monitor).
MY IMPLEMENTATION IDEAS (to illustrate my proposal, no firm decisions):
- Make a simple rectangular "monkey coffin" / monitor style box, good old three way. Shoud be easy enough to make on a kitchen table. Dimensions roughly 30 x 65 x 30 cm or so (will depend on the requirements of the drivers and box tuning).
- For "weak amp compatibility" I set the efficiency target to 92 dB/2.83V/1m, with bass extension to 50 Hz (-3 dB). Achieving this will not be very easy.
- The impedance curve should be flatish and qualify as "8 Ohm". This means we can't "cheat" with the efficiency target by using low-impedance drivers.
- Use high-quality drivers/parts with the right tech specs for the task. The look of the drivers has to be "right" for a HiFi system in a home environment, but is second priority after the tech specs (people may not want to build a speaker that does not look "right").
- Woofer: 10" looks like the right compromise between size and efficiency to me. I modelled the Fane Sovereign Pro 10-300SC in a bass reflex box (28 litres) and got an SPL of almost 96 dB (2.83V/1m) into half space extending to lower than 50 Hz (-3dB) (see attached plot). That's 90 dB in full space, and with a bit of help of the floor and walls, 92 dB is not unreasonable. Other woofers might work well, too. I am also looking at Volt woofers, but I am really open to suggestions.
- Midrange: Needs to keep up with the SPL requirements, so many of the conventional "HiFi" midranges are out. From the top of my head, I can think of the Supravox 135 LB (advertised as a "full range", but...), Accuton C168-6-990 (maybe a bit too large and expensive!), or the Volt VM752 dome (not a cone as I said earlier, but VERY good, and expensive). Or a Veravox 5S? I am open to suggestions!
- Tweeter: I have not thought about tweeter choices much and I guess there should be quite a few units that would work well. I am a big fan of the Scan Speak D3004/6640 beryllium dome, but that does not qualify here because it's a 4 Ohm unit. The SB Acoustics Satori TW29BN beryllium might be an alternative, although it's also a 4 Ohm unit. The TW29BN is at about 97 dB (> 3 kHz), so it might work out to the 8 Ohm spec with an attenuation resistor in series. I am open to suggestions!
- Cross over frequencies: that will depend quite a bit on the driver choices. However, if possible, I like to set the woofer/midrange x-over frequency such that it fits the baffle-step centre frequency. This makes it easier to compensate the baffle step by fiddling with the woofer SPL vs midrange SPL.
- I have not considered any cost limits for now. The poll results do not seem to indicate any upper price limit. This is something that needs to be defined along the way, and will determine the choice of the drivers and other parts.
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haha that's the thing, I only read the reviews and good ones on basszilla and havn't heard it myself, so i would appreciate it if you have told me that because it will save a lot of headache later on ! I m not insisting on this if it sucks
so 2 questions tho, why it sucks ? I mean, it has very high sensitivity, flat respond, and the Fostex is a well known driver, so you think the whole setup doesn't fit together or the speaker is not well designed ?
and why not ported woofer ? you don't like ported woofer design in general or just in this case ?
I m curious to know.
Your post reminded me of this: the silent runner.
Power hungry but easier to fit in a modern interior than big monkey coffins.
Nice suggestion!
Full Disclosure: I didn't vote for the 3-way Classic format. I voted for the horn-loaded 3-way ( the more expensive version of the 2 ).
I'm still following the thread because I'm curious what (82) other voters are looking for in a 3-way.
- I also feel it's critical that a majority of those who voted for the winning format articulate why they want this style of speaker ( if they care about the success of the project ).
Quick update:
- I modelled the Volt BM251.3 in a 34 litre bass reflex box, which yields about 2 dB higher SPL than the Fane at the same cut-off frequency. Looks good!
- Midrange: forget the Veravox, that seems to be obsolete since a few years.
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