Help for beginner

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Since my first visit here I did my homework, so that I have more questions (was it the deal?).
The purpose is to do 2 speakers to connect to my virtual-pipe-organ (its computer-based, the program is GrandOrgue) and these speakers would be dedicated to pipe-organ music. I would like also - if not too contradictory - that these spks can be placed for concerts in bigger rooms, lets say till 250 seats. Somehow transportable and powerful enough for this use.

I looked at spks for musical instruments (bass-guitar and Ondes Martenot). Both have fullrange speakers, and both are dipole-open (more or less 35-100% of the surface of the front panel is opened on the rear-side).

I suppose there are reasons why musical-instr. use full-range spk in open-dipoles, but no clue. Why?

In my case I need a range of 32-16000Hz, and I suppose its a good idea to go the way that others gone. So I came to following possibilities and I dont know what to decide:

- full-range, double-horn (speaker totally enclosed), vertical
- full-range, simple opened cabinet
- full-range, double folded rear (G-form - would it be better than an open-dipole?)
- two-way (would it be ok with a full-range too?) horizontal, omnidirectional with a cone on the top, 8-sided-cabinet.

Whats better for this aim, and with wich diameter-driver?...?...?

Thanks in advance
 
Since my first visit here I did my homework, so that I have more questions (was it the deal?).
The purpose is to do 2 speakers to connect to my virtual-pipe-organ (its computer-based, the program is GrandOrgue) and these speakers would be dedicated to pipe-organ music. I would like also - if not too contradictory - that these spks can be placed for concerts in bigger rooms, lets say till 250 seats. Somehow transportable and powerful enough for this use.

I looked at spks for musical instruments (bass-guitar and Ondes Martenot). Both have fullrange speakers, and both are dipole-open (more or less 35-100% of the surface of the front panel is opened on the rear-side).

I suppose there are reasons why musical-instr. use full-range spk in open-dipoles, but no clue. Why?

In my case I need a range of 32-16000Hz, and I suppose its a good idea to go the way that others gone. So I came to following possibilities and I dont know what to decide:

- full-range, double-horn (speaker totally enclosed), vertical
- full-range, simple opened cabinet
- full-range, double folded rear (G-form - would it be better than an open-dipole?)
- two-way (would it be ok with a full-range too?) horizontal, omnidirectional with a cone on the top, 8-sided-cabinet.

Whats better for this aim, and with wich diameter-driver?...?...?

Thanks in advance


You'll have trouble finding a single driver Full Range driver based system capable of the full bandwidth described at "realistic performance levels" in even a moderate domestic environment, much less the larger venues. For the latter you probably really want to consider a multi-way sound reinforcement system - compression horn & bass bins - a la VOTT etc.
 
depends on what must be realistic performance level.

I dont mean if the-big-tutti-of-the-toccata-in-d is not loud enough. 99% of the organ-music I wanna play (practice at home and popularize organ-music) is not loud and sounds better without knocking out people. So I suppose the power will not be the main issue (anyway people who invite me will have to check for a PA if this doesnt suit with my speakers). Of course no problem to go multi-way, but till now no clue...
 
Wonderful, i didnt knew this but unfortunately, no one for (where are the plans?)
If I go 2-way with a bass-reflex... questions about the port. Can this be made tunable with wood (octogonal) as material (without disadvantage)? And what differences are there bettwen a smaller and and greater port-diameter with the same tuning? Oooops questions and questions
 
I suppose there are reasons why musical-instr. use full-range spk in open-dipoles, but no clue. Why?

Part of the reason is a lot of people, including me, like the sound. The other reason is that open backed cabinets have a (mostly) dipole response pattern, and it is convenient to have the null zones to the sides of the speakers when playing live. It helps reduce feedback issues.

They are less efficient in the bass frequencies, since the bass rolls of at 6db/octave below a frequency determined by the baffle width (in addition to the driver's natural roll off). That is why they are commonly used for guitar, but rarely used for bass and keyboard instruments.

A real pipe organ has response down to as low as 16hz. For realism, an F3 down to 32 Hz or so would be nice, but maybe not practical. PA systems often don't go any lower than 60hz or so, because it just isn't needed with rock/pop music. For an avant garde art music project, as this appears to be, you may want to do better.

Practically speaking, OB is feasible, but for a 250 person room, I would want about four 15" speakers per side (8 total). Maybe use a 15" coaxial for one of them, for the high frequencies.

It would be much cheaper to build bass reflex or ML-TL cabinets, obviously.

There's no reason the cabinet can't be octagonal. Actually it's a very good way to go, if you're willing to do the extra work. I made some octagonal cross section TQWT enclosures years ago that turned out very well.
 
Thanks again!

I had to look up what ML-TL is - this needs a long tube, even folded. Its big and heavier than bass-reflex. I disregarded bass-reflex till now for stupid reasons (all banal stuff that looks fragile in banal shops is bass-reflex) but considering a little size and weight for transport, and the need of powerful sounds at 32Hz (I dont need the 16Hz-pitch for my aim but the 16' should accept a bombarde 16* without burn out) this seems indeed to be it.

Now about organ sound and my project.
- 16' - 32Hz is good anyway. But at this freq. the sound must be still powerful. One well-known organbuilder build the first octave (down from 64Hz to 32Hz) winning power at each new note downside for some stops. This should not be "eaten" through a standard speaker (if possible), because this is a remarquable caracteristique of this organ style.
- the highest fundamental note is more or less 16000Hz (top c of a 1'-Stop). At this level, organbuilders let all sound like flutes, and this level is for musical reasons more seldom. Lets say 12000Hz is honest, more is better for clarity.
- transport is an issue. Here the only possibility is a taxi, but all are little chevrolets or Hyundai. So Laptop+2speakers+Combo-organ+full-pedal+foldable-bench+Amp (where do I find a software equalizer?) thats already two taxis and I need one person in each taxi. Big TLs, even very thin, or big folded TLs doesnt even enter in these taxis.
- The choice of speakers and port is an issue too. Here speakers are just a way to bombard the street with announcements!!! Visaton and other known brands are unknown. Only chinese stuff without datasheet in the web :confused: Hard to find drivers with datasheet. But all seems to be made for bass-reflex - I didnt knew before that there are drivers for sealed, others for ported etc. Quality ports are also inexistant. In my case I will do it with wood.

So I think of
- bass-reflex (which diameter???) with at least
- 12'-drivers-50-Watts,
- 100liters inside (in ratio 10:12:14 since its said to be a good ratio)
- 18mm plywood, and
- 4 sealed high-mediums (4'?) in 4 directions (sides, front and one for rear/up) for omnidirectionality, indenpendant from the woofer.
- Crossover diy butterworth 1st order to have a smooth passage. I think of trying with different frequencies.

I would be pleased to read if this is a good direction, or what is to reconsider.

*here a bombarde 16' to have an idea: Albi cathedral organ Beauvarlet-Charpentier - YouTube comes down to 35Hz
 
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