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Old 6th December 2005, 04:47 PM   #11
Previously: Kuei Yang Wang
 
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Konnichiwa,

First, I agree, if all you need is a cheap semi-decent Monitor the Behringer or others of a similar ilk give a turnkey solution, reasonably affordable.

HOWEVER, I do not think they make particular good monitors, be it Genelec 1031A or Behringer 2031A or Makie 824HR.

This is where DIY to a reasonable extent has it's uses.

Let me briefly propose a simple to DIY "studio monitor" system for nearfield/meter-bridge applications and the reasoning behind.

First, monitors like the above are not neccesarily time coherent nor do they have too even off axis response in the midrange (critical) and the 2-Way system means that at higher volumes the midrage invariably turns to mud as it is modulated by the excursion of the (nonlinear) woofer.

The solution is to go for 3 Ways using a coincident Midrage/Treble driver that is reasonably time coherent. Seas makes one 6.5" TPX cone coax that fits the brief well.

The cone acts as waveguide for the tweeter and makes sure of even off axis resonse if a suitable crossover is employed. We need to stop this cone from moving, so we use in a traditional 2-Way style cabinet the Seas Coax instead of the Waveguide/Tweeter combo and operate it down to maybe 150...200Hz.

Below this we use a serious "airpump" (meaning very long throw) 8" or 9" woofer, sealed box, if it was me I would fit a second driver to the back of the cabinet, not a passive radiator, but an active one.

the enclosure is then basically two compact sealed chambers, easy to build, don't forget acoustafill, long hair wool or whatever you like (I like carpet underlay felt on walls with wool or acoustastuff in the actual cavity, no foam please).

As electronics to drive the whole shooting match I'd use probably a Behringer DCX2496 or similar Digital Crossover and a bunch of suitable Amplifiers. Something like this needs only limited DIY (Speaker enclosure) and by careful use of the parametric equalisation in the digital crossover, as well as that of the limiters can be made to offer a performance reliability well past that afforded by the all in one jobbies.

The amplifiers BTW could be build DIY, using the various "Gainclone" resources I'd probably suggest a classic 4-Channel LM3875 Gainclone for mid/treble with suitable attenuation to match the DCX Outputs and something based on Bridged LM3886 for the (sub)woofers, again 4 Channels to drive the front & rear 8" woofer seperately.

All in all 12 "Chipamp" PCB's from whatever source, 1 suitable big transformer for the Mid/Hi Channels with around 24V+24V AC and another big one for the Subs with 24V+24V.

Maybe best to build two big "amplifier cubes" each one with two bridged LF channels and two single ended MF/HF Channels.

Freeware frequency & impulse measurement software exists, measurement mikes can be purchased (good idea for any commercial outfit to have a semi decent one at hand anyway) and there are instructions on-line how to set up and equalise active PA Setups, this little monitor is no different.

Sayonara
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Old 7th December 2005, 04:11 AM   #12
Thunau is offline Thunau  United States
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Sorry Quei, I have to disagree with you here.
First, how do you know that the Genelecs and the Mackies are not "reasonably" as you put it, time coherent? Have you measured them?
Also, the off axis response is a big design factor for the Genelecs and Mackies. That's why they use tweeter wave guides that exhibit similar diectionality at the crossover frequency as the woofer. A typical flat baffle loudspeaker has to be crossed over much too low to exhibit smooth power response (even then it ends up tilted toward lower frequencies) which leads to stressing of the tweeter.
A 6.5" coax such as the Seas has a natural 10k dip on axis in FR, which is related to the geometry of the design and can not be equalized out. That prevents it from being a good nearfield (but not a decent home hi-fi speaker).
The Tannoy design with its short "tulip" horn controls it a bit better. Incidently the Tannoy monitors while good, are not considered inherently superior to non concentric studio monitor designs.

As to making monitors, amps and crossovers from scratch, using free tools from the web, you are kidding, right? By the time one gathers the tools, parts and basic knowledge how to do it, goes through multiple designs to acquire the necessary experience and ends up with something rather generic sounding and still looking like a DIY project , just to be turned down by prospective clients because he doesn't have a "real" studio monitor, he could have saved the money to get a set of Mackies (incidently remarkably good nearfields) and used them to earn enough to afford a set of 3-way Dynaudios or Westlakes, all while gathering priceless skills and knowledge how to record and produce music.

I've been down that road myself. I owned a recording studio and decided to save money and build a set of nice 3-way active monitors myself. I spent a lot of time and money (I even used a Kef coax for my mids/highs as you suggested above for my first design), I bought lspCADpro, learned to use it, build another set using Dynaudio, BG and Vifa components and 5 years later still don't have monitors as good as the money and time spent could have bought me in the first place.
I picked up a cool hobby along the way and a lot of knowledge, but I would not put my best design against a Westlake, ATC or Munro.
Yes, it cost me less money, but even at minimum wage, my effort spent put me right back in the price range of real-deal studio monitors.
The poster who started this thread should ask himself- who do I want to be? A speaker designer or a recording engineer? He can be both, but it will take some time to learn both skills and he could jeopardize his chances at one by pursuing the other. I think you are underestimating the engineering knowledge needed to make a real good monitor. Just look at Behringer product. They do OK with their electronics, but a good studio monitor is beyond them.
Just my (somewhat informed) opinion.
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Old 7th December 2005, 10:43 AM   #13
kexik is offline kexik  Slovakia
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thunau: 100% true. no way to create reasonably good DIY nearfields, at least not its acoustic part. that's why I adviced to buy commercial cheapos and try to improve its weak features (terrible power amp). design of mixing monitors is principially different from hi-fi approach, by the way, 3-way design is absolutely RARE in this class of monitors, due to phasing problems...
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Old 11th December 2005, 02:12 PM   #14
gev is offline gev  Turkey
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enjoy
http://www.nmine.com/multiamp.htm
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Old 13th December 2005, 08:50 AM   #15
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AFAIK the Genelecs use high-order LR crossover which means that they are by no means time-coherent.

Quote:
by the way, 3-way design is absolutely RARE in this class of monitors, due to phasing problems...
I agree on the RARE. But if you have once heard a K+H O300 (near - to mid- field 3-way active) you wouldn't want to listen to a Genelec anymore. They are quite pricey though.

Regards

Charles
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Old 18th December 2005, 03:32 AM   #16
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Default Studio Monitor

I agree with both Thorsten AND Jan. ALthough personally I intensely dislike the MACKIE HR 824 for their underpresentation of the critical midrange bands (measured ruler-flat, ha!). I own both GENELECS and the MACKIES and I am a professional sound engineer. I think DIY studio monitors WILL do at least one thing for you: it will offer you critical insight into HOW studio monitoring influences your artistic choices as a professional mixer/engineer. For that I believe there is no substitute than to spend endless hours experimenting with drivers, speaker design, and amplifiers. However, it takes more than this awareness to be compatible with the market, and if you tend to have clients or other engineers in your facility, then DIY is problematic, not only for the lack of "brand name" recognition. The only professionals out there that usually can get away with self-made speakers are mastering engineers. Nevertheless, I disagree with the notion that it is impossible to make a good near-field monitor. I would like to quote George Massenburg here who put forth the notion that a monitor either works for an engineer or doesn't. My own opinion, as near-fields are concerned, is that if you will be the only one listening to it, then the ONLY thing that matters is how WELL you are familiar with their sonic signature and how it translates to other systems. The fact that most professional mixers have been listening to a certain low-budget passive two-way monitor by Yamaha for the last twenty-five years speaks for itself.
Concerning, driver modulations (FM or AM), this could be taken care of by adding a larger low-frequency cabinet underneath the monitors with the appropriate cross-over. Even then, the MACKIEs do not have a revealing midrange, and I think the problem lies with the 8" VIFA poly driver - or my ears

cheers
RB
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Old 18th December 2005, 05:58 AM   #17
JZatopa is offline JZatopa  United States
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"My own opinion, as near-fields are concerned, is that if you will be the only one listening to it, then the ONLY thing that matters is how WELL you are familiar with their sonic signature and how it translates to other systems"

This is true but it leaves out the "details". Mix transportability is very important but so is being able to hear what you are actualy recording. I think that the DIY comunity needs a good DIY nearfield monitor. Noone seems to want to actualy want to do this though. I personaly like coaxial speakers and think they are a great compramise between convential speakers and single drivers. I wonder if the newer h1353 seas coax would work because it's 10khz dip looks smaller on the graph. The speaker would be time aligned so all someone would to do is design an active crossover with built in eq to flatten the response within 1db from 50-20khz that could be used with two stereo chip amps. Then again, most of the DIYers out there may not have the equipment or skills to do the designing.
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Old 18th December 2005, 01:49 PM   #18
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Default FULL-RANGE vs. MIXING MONITOR

Quote:
Originally posted by DJNUBZ
"My own opinion, as near-fields are concerned, is that if you will be the only one listening to it, then the ONLY thing that matters is how WELL you are familiar with their sonic signature and how it translates to other systems"

This is true but it leaves out the "details". Mix transportability is very important but so is being able to hear what you are actualy recording. I think that the DIY comunity needs a good DIY nearfield monitor. Noone seems to want to actualy want to do this though. I personaly like coaxial speakers and think they are a great compramise between convential speakers and single drivers. I wonder if the newer h1353 seas coax would work because it's 10khz dip looks smaller on the graph. The speaker would be time aligned so all someone would to do is design an active crossover with built in eq to flatten the response within 1db from 50-20khz that could be used with two stereo chip amps. Then again, most of the DIYers out there may not have the equipment or skills to do the designing.

Your point is well-taken DJNUBZ. I would contend, however, that what you are looking for is a full-range portable monitor (contradiction in term ?), not a near-field *mix* monitor in the traditional sense of the word. For a mix I can usually assume (and check) that the recording engineer has done their job and provided me with *clean* tracks, ie. no problems in the low and highs. If necessary, this can be double-checked with headphones. During mixing the midrange is most critical to me, since this is where most of the instrument's timbres pile up. And since I like to mix at very low levels (in order to balance fatigue), such a near-field also does not need to withstand the enormous abuse that clients usually present to the far-fields (especially in Hip-Hop and Rap production!). I have followed Thorsten's philosophy in this respect and considered full-range drivers that only need *help* on the extreme ends of the frequency bands. Hence, I have been experimenting with the CSS FR drivers as a possible alternative to commercially available self-powered near-field monitors, and my full-range system currently uses the MANGER BW transducer as a midrange, augmented actively by a low (Volt Radial) and high frequency driver (Scan-Speak Revelator/LCY 130) as *needed.* If I want a *constricted* full-range system that is more revealing than the CSS drivers, I simply mute the low and high drivers and run the MANGERs in full-range. You are correct, that some drivers are simply better in terms of their time response than others, and the MANGERs are a great example when heard over the little CSS 4.5" drivers (at 15 times the cost!). The problem with the CSS mini-monitors is that they are quite inefficient and therefore need a relatively high-powered amp. A self-made chipamp, IMHO, would work only if used in bridge mode. Personally, I drive them with a big ol' sound reinforcement amp (Crown K1). In the STUDIO, of course, I got the DYNAUDIO M3As, with the massive Esotar tweeter ad far-fields.

cheers
rb
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Old 18th December 2005, 07:25 PM   #19
JZatopa is offline JZatopa  United States
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Russian, I was thinking that this project was more along the lines of what a project studio would need. Most of the smaller studios around me not only record but also do the mixing. After the mixing the client has the option of sending the porduct to mastering or to just use it the way it is.
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Old 18th December 2005, 09:42 PM   #20
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Quote:
Originally posted by DJNUBZ
"I think that the DIY comunity needs a good DIY nearfield monitor. Noone seems to want to actualy want to do this though. I personaly like coaxial speakers and think they are a great compramise between convential speakers and single drivers. I wonder if the newer h1353 seas coax would work because it's 10khz dip looks smaller on the graph. The speaker would be time aligned so all someone would to do is design an active crossover with built in eq to flatten the response within 1db from 50-20khz that could be used with two stereo chip amps.

I think the following is quite feasible for DIY. I would submit as an idea for your consideration a near-field monitor with two CSS FR 4.5" drivers in a sealed enclosure, driven by four chipamps, two each bridged for the upper and lower end. Crossover would be active, OR passive. Currently I have this combination running actively bi-amped with X-over around 196Hz (via Behringer DCX), which will also compensate for the small baffle such an enclosure would have (BSC). Result: pin-point imagining with less distortions on the bottom end due to driver doubling. I suppose one would call this a 1.5 way?
I still think that perhaps one of the new SPEAKERPOWER digital modules would work brilliantly for this kind of application. I am looking at a Bi-amp powerpack with 250W/250W (see pix). But I do not know whether these are available for the DIY community.

cheers
rb
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