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Scrie un subiect nou Răspunde la subiect  [ 16 mesaje ]  Du-te la pagina 1, 2  Următorul

Trapezoidal cabinet?
Trapezoidal 88%  88%  [ 43 ]
Non-trapezoidal 12%  12%  [ 6 ]
Voturi totale : 49
Autor Mesaj
 Subiectul mesajului: Trapezoidal cabinet?
MesajScris: Lun Noi 28, 2005 3:30 am 
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Membru din: Joi Noi 17, 2005 6:43 pm
Mesaje: 5
A trapezoidal cabinet or not?

Is this project going to be for the unskilled people as well? If not, would anyone here experience problems with making a trapezoidal shape?

If it's going to be trapezoidal, what would be the desired angle and/or measurements?

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 Subiectul mesajului:
MesajScris: Lun Noi 28, 2005 9:32 am 
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Director General 0766332366
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Membru din: Joi Oct 27, 2005 7:33 pm
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I personally preffer trapeizodal cabinet with 15 degree angles, they look so better than square ones, and they are easier to array as well

:wink:

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ing. Mircea Bartic
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Poweraudio Romania
Str. Gheorghe Sincai, Nr.26 Bistrita
Telefon: 0766332366
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 Subiectul mesajului:
MesajScris: Lun Noi 28, 2005 7:11 pm 
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Membru din: Dum Noi 27, 2005 10:25 pm
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I think the trap angle should be made, so that when 2 or more cabs are tight together they array correctly. This would make setting up your system a lot easier.


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 Subiectul mesajului: Cabinet difficulty
MesajScris: Lun Noi 28, 2005 7:20 pm 
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Membru din: Dum Noi 27, 2005 10:25 pm
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I think the internal structure is going to be fairly complex, so this in itself may put some people off building.
I think at the end of the design there will be a cutting list with panel sizes and angles, so your local woodyard can cut the wood.


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 Subiectul mesajului:
MesajScris: Lun Noi 28, 2005 7:32 pm 
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Membru din: Joi Oct 27, 2005 7:33 pm
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of course
we will make detailed plans for building,

Pictures will be available from me (at least) if I decide to use this design as a mid-top cabinet for the 4 punsishers I'll soon start building

_________________
ing. Mircea Bartic
Director general

Poweraudio Romania
Str. Gheorghe Sincai, Nr.26 Bistrita
Telefon: 0766332366
E-mail: office@poweraudio.ro
www.poweraudio.ro
facebook.com/poweraudio.romania


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 Subiectul mesajului:
MesajScris: Lun Noi 28, 2005 7:39 pm 
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Membru din: Mie Noi 16, 2005 8:18 pm
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in order to build a mid top which arrays by close stacking (very desirable and the the spec to which i think graeme and i are pushing) it is necessary to go trapezoidal. in order to build a horn into such a box compound mitres will be required, there is no way around this.

carpentry may well be daunting but we should endeavor to make it less so, not only by providing a detailed parts list and cut sheets, but also by making a wiki for the build which could contain some very detailed instructions, photographs and illustrations.

the very nature of what we are trying to do will, i suspect, entail complex woodwork. whilst it can't go crazy i strongly believe the design should not be compromised because the carpentry looks hard.

james.

ps. you're right nexus, traps look the don.


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 Subiectul mesajului:
MesajScris: Sâm Dec 24, 2005 10:27 am 
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Membru din: Mie Noi 16, 2005 7:32 pm
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If it's not a trapezoidal design, we may as well just build the X-tro.


:)


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 Subiectul mesajului:
MesajScris: Joi Dec 29, 2005 1:43 pm 
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Membru din: Mar Dec 06, 2005 12:52 am
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Localitate: France
Definitely trapezoidal and we shouldnt forget flyingpoints.


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 Subiectul mesajului:
MesajScris: Joi Dec 29, 2005 4:08 pm 
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Membru din: Joi Dec 29, 2005 4:04 pm
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I will opt for a trapezodial cab too!
I am already thinking of a 2 x 10" + 1" for a long time
2 x 12" is the most versatile probably, 10" would be smaller and lighter though. If we can find the right 10"-ers (read: good sound, low price)

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 Subiectul mesajului:
MesajScris: Joi Dec 29, 2005 4:36 pm 
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the problem with 10" drivers will be going low enough

we nwwd to cross at least at 90 Hz to the subwoofers

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ing. Mircea Bartic
Director general

Poweraudio Romania
Str. Gheorghe Sincai, Nr.26 Bistrita
Telefon: 0766332366
E-mail: office@poweraudio.ro
www.poweraudio.ro
facebook.com/poweraudio.romania


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 Subiectul mesajului:
MesajScris: Vin Dec 30, 2005 12:45 pm 
Yes, i know.
But there are 10"drivers that might do the trick, f.i. the 18sound 10MB400 starts at 65 Hz, and has a very high efficiency of 100,5 dB
I must be honest, at about 100 Hz. it's only 90dB left, but still, could be good to investigate. Ill run it through winisd when i have the time.

I am using very small, front loaded tops with a 10" and a bullit (Celestion k10-200 / hf50), and i am very happy with them, it's just that i need a larger system too.
My current 2 x 12"/1" does the trick, but i have only 2, and i want 4, so now is the time to think of the future for these.
I like the X-tro design too, but i definately want trapcabs, and i want lightweight also. I can stack my current bigtops by myself, on a standing 2 x 18"


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 Subiectul mesajului:
MesajScris: Vin Dec 30, 2005 12:48 pm 
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Membru din: Joi Dec 29, 2005 4:04 pm
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Sorry, i am the 'mistery guest' (forgot to log in)

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 Subiectul mesajului:
MesajScris: Vin Dec 30, 2005 4:36 pm 
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Membru din: Joi Noi 17, 2005 3:22 pm
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I don't think there would be much problem getting a 10" low enough - the horn loading will lower the driver's Fs quite nicely. I have just finished a couple of horn subs using the Beyma 10G40, and these go down to 40Hz quite nicely - it's all in the horn.

From simulations and objective listening, it seems that a small driver loaded with the correct length horn can get down to a given frequency with more efficiency than the "brute force" approach of a larger driver on a shorter horn. However, the larger driver can get lower extension at lower efficiency as it is not as dependant on the horn loading (note the two 15s required to keep up with one 8 in the XTRO). I intend to do some actual measurements shortly between the two approaches - albeit with subs, but the results should be applicable to low mid horns as well. I have some old Cerwin Vega double 18 horns, and will compare one of these to two of the new 10" subs (boxes will be about same physical size and number of drivers). I am expecting that the 10s will be more efficient down to their sharp 40Hz cutoff, but the 18s should be able to still keep going a bit lower.

Using a smaller driver WILL require a longer horn - longer than most of us would consider a reasonable cabinet depth, so bending the horn would be neccessary. Note that I said "bending" and NOT "folding" - the horn bend (could be 180 degrees no problem) would have to be reasonably smooth with a reasonable inside radius in order not to harm the upper response, and especially when using a trapezoidal cabinet, will increase construction difficulty. However, when it comes to trading the extra cost of a larger driver (or two), the extra weight and the extra power requirement against more complicated joinery, I opt for the more efficient solution.

I am soon to be doing some more experimentation (probably not till February, as I will be tied up with production during our upcomming annual 2-week Country Music Festival) with the low-mid section of some line array boxes I am developing. These will utilise two horn-loaded 8" drivers either side of a dual 6" + 1" module some of you have already seen. I am trying to get these to cover down to 100Hz, and will probably be using port assistance (such as some Martin boxes) as well as the mutal coupling between two flares to achieve this. If all this works ok, then I see no problem getting a 10" a little lower. As we are talking about a narrow dispersion box which will require a minimum of 2 per side, then the mutual coupling of the low-mid horns should assist in keeping efficiency up.

On another note, I will probably have a couple of 6ND410 drivers soon, so a few trials of some ideas applicable to the top end of this box should also happen in February - will report back.

Cheers
Graeme


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 Subiectul mesajului:
MesajScris: Joi Ian 05, 2006 12:23 am 
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Membru din: Joi Dec 29, 2005 4:04 pm
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What would a "normal" trap-BR cab do it we added a horn as a wave guide?
Obviously, we would not have the 'amplification' of the horn, but would it make the directionality of the cab nicer?
I mean a front loaded speaker has a radiation that varies with the freq.
Would a horn/wave guide of let's say 50 deg. make it a 50 deg cab, with the sound of a standard front loaded BR? or would it be a total crap?
It feels like a good idea to me, but ........?

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 Subiectul mesajului:
MesajScris: Vin Ian 06, 2006 1:30 pm 
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Membru din: Joi Noi 17, 2005 3:22 pm
Mesaje: 12
Localitate: Australia
Carl,

Whilst the idea might look as though it should work, the lower frequency point at which a waveguide can control dispersion is governed by the mouth size of the horn, and unless the box is quite large, that ain't going to happen for low-mid frequencies. For a reasonable size box, I would not expect to maintain any sort of pattern control below 400Hz. Fortunately, at lower frequencies, comb filtering is much less of a problem due to longer wavelengths and ear insensitivity, and the overlapping patterns become more constructive as the frequency goes down. I think the main goals with this box is tight pattern control on the highs and hi-mid, with maximum efficiency on the low-mid to keep up.

Cheers
Graeme


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