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Bedroom music Need to build small speakers
Bedroom music Need to build small speakers
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Old 31st December 2010, 12:59 AM   #1
Moondog55 is offline Moondog55  Australia
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Default Bedroom music Need to build small speakers

I need to use what I have and they need to be small.

Aussie query regarding the Jaycar CW-2315.

I hate to waste a Vifa M-22 in a too small closed box and I have a pair of the polycones sitting on a shelf, the P-13s need to be used and I will match them with the D-27 so the XO is no problem there, I just need a little extra bass and power handling and help with a 2.5 way.

Assuming I put the little 6inch in a 15liter sealed box 250mm wide and use a single inductor where is the best place to add the baffle step? P-13 rolls off at 200 in a small sealed box of 4litres ( has to be sealed- we have no room to spare and the finished box needs to fit the existing wall mounted stands ) Baffle step starts at ~400hz I assume and the little woofer has nothing to speak of below 50Hz
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Old 31st December 2010, 07:21 PM   #2
PeteMcK is offline PeteMcK
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Hi Moondog,
If that's the CW-2135, even in 15 L I'd still vent them, tuned to ~50Hz - this will give a slight hump at the low end, but get you down to 50Hz. Closed, they'll roll off at ~ 100Hz.
I can dig out an impedance curve if you need it. The cw-2135's won't handle lots of power down low, but are good to medium - high levels.
If your P13s roll off at 200, that's where I'd size the inductor for. (or just try the biggest ones you've got on hand !)
cheers,
Pete McK
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Old 31st December 2010, 08:24 PM   #3
Moondog55 is offline Moondog55  Australia
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Happy new Year Pete
Yes my poor reading and typing, they are the CW2135.
Unfortunately I have to use a sealed box because of the position of the wall mounted brackets ( which were placed for the pair of Sansui book-shelfs ) I do have several discrete sub boxes to fill in the bottom end if we feel the need.

I have still not ever built a series XO and thought this was the ideal opportunity as these little speakers will never ever have to play at party levels and I can give the midrange priority
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Old 31st December 2010, 09:52 PM   #4
Moondog55 is offline Moondog55  Australia
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I just modelled both sealed and ported in small boxes i like the shape of the roll-off better with the sealed box, this is a very small bedroom.

i could get the overall size of the box down if I had a tweeter here that would come down to meet the P-13, unfortunately the D26NC needs at least a second order XO quite a bit higher than 2700 so i don't think it is suitable for a series XO.

Unless some-one has a cross-over already developed using this combination that is
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Old 1st January 2011, 11:10 PM   #5
Moondog55 is offline Moondog55  Australia
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i have been doing some work on the XO using information from AndyGs site ( Thanx Andy ) and David Weems book.

Without modelling I know that what I have is just a starting point but I would appreciate any comments, "Speakerbug" have a good range of aircore coils and if I need a certain value they do not have ( 0.57mH ) I have assumed that going to the next closest standard value but with the lowest DCR is better 0.56mh being less than 2% different but half the DCR.

Do I understand correctly that with series XOs the cap in not directly in the signal path and quality of the cap is therefore of less significance?? and I can use the cheaper Jantzen Audio Crosscap and save some real money??

Second question now, how low can I cross a D27-45-06 using a first order series?? I have chosen 2700Hz as a starting point which is quite a bit lower than the little 2-way reference project using the same drivers.

Should I also use Vifas Resonance trap filter as part of the actual tweeter or just not use anything


P-13 will of course use a Zobel, ~15uF + 8R

I may also ( will most probably ) need an additional conjugate circuit to counter the woofers 12dB peak in response centered @ 2100Hz
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Old 2nd January 2011, 06:50 AM   #6
Moondog55 is offline Moondog55  Australia
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I could live with these "AS IS" just adding a little depth to a P-13 makes quite a difference even if it is a cheap woofer

This is just a quick baffle test to check my dimensions.
5.6mH on the woofer 3.3uF on the tweeter and some ploy and felt padding, I just love cardboard.

The 2YO just loves to help, the sharper and more dangerous the tools the more she likes to get involved
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Old 2nd January 2011, 06:51 AM   #7
Moondog55 is offline Moondog55  Australia
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more pix of the baffle itself
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Old 2nd January 2011, 11:11 PM   #8
Moondog55 is offline Moondog55  Australia
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SWMBO now wants to hear the mid tweeter combination using the M-22 woofer rolled off at the same frequency, even tho she thinks the boxes may be too big, she can hear the peak in the little Response woofer better than I can. Therefore I am making some quick test boxes out of cardboard, they would be finished except I have run out of quick-set PVA
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Old 3rd January 2011, 12:30 AM   #9
CLS is offline CLS  Taiwan
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Saw this topic when it started and I thought to myself: why does a bedroom system need to be put in this 'multi-way' forum instead of much simpler and smaller 'fullranger' type...?

Now this 3-way is coming up.

You must have a very big bed room. And look at those (lethal) huge magnets! I bet it'll be very good at being used as a wakeup call
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Old 3rd January 2011, 12:57 AM   #10
bigbeck is offline bigbeck  United States
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Yeah, I just made a bedroom speaker system from 5 1/4" 15 watt full range car speakers. I made .5 cubic foot ported cabs hooked up to a 20 watt chip amp. Sounds really good in my 10' x 12' bedroom. However, it does not sound good at all in my family room - total rubbish.

Maybe Moondog does have a really big bedroom or he likes his music really loud.

Don
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