DIY Full-range Bookshelf for a Beginner

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#23
lostandconfused said:
I can't offer my opinion, as my first practice builds with the B3Ns are still being built (see below - I'm using the Italian B3N design as it seemed easy to make from offcuts).
Click to expand...

I tested out the half finished boxes from this design last night:

Google Translate

Despite the not "ideal" placement (on stone floor, clamped together, no roundovers on the baffles etc), the B3N speakers sounded really quite good despite only being powered by my lowly t-amp.

No filter, and no break-in yet, so you can really hear the high-hats... but they sound miles better than my TV-speakers (surprise), go plenty loud enough (not even at 12 o'oclock on T-amp).

So this is what DIY speakers are all about? Scott - if you have a spare $25 for drivers and some plywood lying around, these are a pretty easy build. Just do it!
 
#24
lostandconfused said:
I tested out the half finished boxes from this design last night:

Google Translate

Despite the not "ideal" placement (on stone floor, clamped together, no roundovers on the baffles etc), the B3N speakers sounded really quite good despite only being powered by my lowly t-amp.

No filter, and no break-in yet, so you can really hear the high-hats... but they sound miles better than my TV-speakers (surprise), go plenty loud enough (not even at 12 o'oclock on T-amp).

So this is what DIY speakers are all about? Scott - if you have a spare $25 for drivers and some plywood lying around, these are a pretty easy build. Just do it!
Click to expand...

I don't know if I'm having a brain cramp, but are the dimensions as stated correct? I'd guess they are metric, but do they need to be multipled by ten, as in centimeters?
Plus, the TS parameters on PE list the FR as 100-7000. Even the graph shows them dropping considerably above 10K. Clarification/education/enlightenment??? Thanks.
Mike
 
#25
mikje said:
are the dimensions as stated correct? I'd guess they are metric, but do they need to be multipled by ten, as in centimeters?
Click to expand...

I used them as if they were CM (so multiply by 10 for MM, or divide by 2.54 for inches). I am a total novice at this, but I suppose you could build a supersize version using the measurements as-is, but in inches. Are speakers scale-able like that (linear) or do odd things start to happen...?

mikje said:
Plus, the TS parameters on PE list the FR as 100-7000. Even the graph shows them dropping considerably above 10K. Clarification/education/enlightenment???
Click to expand...

Er. Pass. I can offer none of those three... I'm more at the "build-a-box/listen-to-box" level of design. Anyone with more brain-power care to jump in?
 
#27
lostandconfused said:
So this is what DIY speakers are all about? Scott - if you have a spare $25 for drivers and some plywood lying around, these are a pretty easy build. Just do it!
Click to expand...

That design seems straight forward and yes, the drivers themselves seem cheap enough to boot. Come next paycheck I may look into it, and see if I have any spare plywood lying around.

Out of curiosity what did you use for speaker posts?

Scott
 
#28
TheSeekerr said:
The B3N/S has fairly good extension - http://www.zaphaudio.com/tidbits/HIVI-B3S-FR.gif - falling off just short of 20khz.

A quick sanity check of the line length shows that the dimensions are correct in centimetres.

No, in general, speaker designs are not scalable, and transmission lines particularly not.
Click to expand...

Thanks. Zaph's graph looks much better than the manufacturer's graph on the PE website.
Mike
 
#29
Dave...from MA speaker plans....

Till 70 enclosure for CHR70:

160mm X 290mm X 190mm (interior dimensions)
40mm dia. port, 144mm long,
tuned to 58 Hz, F3:=53Hz
6.4 litre enclosure.

I guess I just assumed you did the design work.

May build an 8 litre box for the Jordans, and put a block of wood (1.6 litre volume)into the enclosure and try the MAs
 
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#30
Nanook said:
Till 70 enclosure for CHR70:

I guess I just assumed you did the design work.

May build an 8 litre box for the Jordans, and put a block of wood (1.6 litre volume)into the enclosure and try the MAs
Click to expand...

No. Not me. When was the last time you saw me put a round port in a box (it was the FE167 break-in boxes your brother is enjoying 🙂)

I am now working on a dMar-Ken70, a deciSize miniOnken.

dave
 
#35
no you generally make stuff with rectangular ports 🙂 ...

me and Mike are supposed to build a pair of boxes soon (I thought it would be yesterday). If we build an 8ℓ ported box for the Jordans, we'll put a wooden block of sufficient volume to get the internal volume to 6.4ℓ. I'll check the tuning of the Jordan box and make modifications to the port. That way we cab "try" the CHRs in a small BR.

These plans were on the Mark Audio site, I believe.

scottder: F3 just means the frequency at which the output of a speaker (or system) is down 3 dB (decibels, which is the unit of measure associated with "loudness" in this case)a better definition (from Genelec loudspeaker systems :
"-3 dB cutoff frequency
The term cutoff frequency (also called the corner frequency or the break frequency) represents the frequency where the energy radiated by the loudspeaker system has been attenuated to one half. At the -3 dB cut-off frequency the sound level has decreased by 3 dB.".

Generally the farther away the F3 is to the tuned frequency, the more bass will be apparent, as the natural cut-off will be less steep


Take care
 
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