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Using 4 to 6 ohm tweeter with 8 ohm crossover

Your diagram has a question mark with the notation "looks like a transformer coil but in parallel with the tweeter". Can you post a picture of that. It is, I think, an inductor used to make a 2nd order high pass filter for the tweeter. If so, it may make what I thought we could do here a lot harder, many times inductor markings are not present on the coils. Please look for any markings on it.

Thanks

Shelly_D
 
crazy-in-az said:
Okay, more info. I was thinking around 24" tall, 13.5" wide, 12" deep. Was planning on making some stands about 8-12 inches tall. I wanted it sealed because I believe bass sounds tighter in a sealed cabinet. It should work with a Sansui 5900z receiver, which is 75 watts per channel, 8 ohm impedance. Plan on a single brace towards the center of the cabinet running from back to front, made out of a 1x2. Want heavy gauge wire on the inside, thinking 12 or 14.
Oh, and I want it done cheap! Not "bad cheap", just on a budget of about $100. :tresbon::music:
Click to expand...

Hi,

You might as well go for a full floorstander than doesn't need stands
and has a more pleasing aspect ratio than your dumpy box shape.

$100 ? for a pair of big speakers ? No. Not a chance of any quality.

Properly vented makes the best of cheaper drivers, its not to be avoided.

rgds, sreten.

http://sites.google.com/site/undefinition/diy (see FAQs)
http://www.zaphaudio.com
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://web.archive.org/web/20090902124715/http://geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.rjbaudio.com/
http://web.archive.org/web/20090902202231/http://geocities.com/woove99/Spkrbldg/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/download.html
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
 
sreten said:
$100 ? for a pair of big speakers ? No. Not a chance of any quality.
Click to expand...
Which is kind of exactly why the idea of a simple 2-way using the existing woofers is not such a bad idea here, even though we have limited info. They are probably decent woofers, and we know the response must be fairly well-behaved since they were run full-range. We also know the proper enclosure. Just need to figured out the highest reasonable crossover point, and pick a tweeter that is sensitive enough. As for my part, I can't really figure out this crossover. Shelly?
 
crazy-in-az said:
Okay, more info. I was thinking around 24" tall, 13.5" wide, 12" deep. Was planning on making some stands about 8-12 inches tall. I wanted it sealed because I believe bass sounds tighter in a sealed cabinet. It should work with a Sansui 5900z receiver, which is 75 watts per channel, 8 ohm impedance. Plan on a single brace towards the center of the cabinet running from back to front, made out of a 1x2. Want heavy gauge wire on the inside, thinking 12 or 14.
Oh, and I want it done cheap! Not "bad cheap", just on a budget of about $100. :tresbon::music:
Click to expand...

Hi,

You might as well go for a full floorstander than doesn't need stands
and has a more pleasing aspect ratio than your dumpy box shape.

$100 ? for a pair of big speakers ? No. Not usually a viable option.
It can be done but requires great skill and a bit of luck with cheap
drivers, that they are to whatever specs they are described, if
you don't have any measuring equipment.

rgds, sreten.

http://sites.google.com/site/undefinition/diy (see FAQs)
http://www.zaphaudio.com
http://www.rjbaudio.com/Audiofiles/FRDtools.html
http://web.archive.org/web/20090902124715/http://geocities.com/woove99/Spkrbldg/DesigningXO.htm
http://www.rjbaudio.com/
http://web.archive.org/web/20090902202231/http://geocities.com/woove99/Spkrbldg/
http://speakerdesignworks.com/
http://www.htguide.com/forum/showthread.php4?t=28655
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/download.html
http://www.quarter-wave.com/
http://www.frugal-horn.com/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
 
sreten said:
Hi,

You might as well go for a full floorstander than doesn't need stands
and has a more pleasing aspect ratio than your dumpy box shape.
Click to expand...

Well, I was going to buy a full sheet of MDF, so I could make a larger set of cabinets.

$100 ? for a pair of big speakers ? No. Not a chance of any quality.
Click to expand...

I meant $100 for tweeters and crossover components. I will spend however much is necessary for screws, glue, MDF, etc. Also, I'm not expecting something as great as Acoustic Research or Klipsch, just decent.

Properly vented makes the best of cheaper drivers, its not to be avoided.
Click to expand...

I will consider that.
:tresbon:
 
crazy-in-az said:
I was thinking of using a full range driver.

I don't quite understand what baffle step means- a little
splainin' please! I looked it up, but was thoroughly confused.
Click to expand...


Hi,

Baffle step is the transition of a driver in a box radiating into full space at low
frequencies to radiating into half space (forwards only) at high frequencies.

The transition causes a 6dB rise in output from bass to midrange. Its actually
known as a bass loss because driver sensitivity its measured on very large flat
baffles, i.e. sensitivity is specified into half space, in real life bass its 6dB less.

e.g. A small high quality speaker to be used in open space on a stand might
have a small 89dB/W/1m driver, but due to BSC (baffle step correction) it
will be designed with the bass at 83dB, midrange and treble at 83-85dB.

If you have a bass unit 4-6dB more efficient than a mid-treble, c/oing
it 1st order (series is better than parallel with real drivers) at the baffle
step frequency (depends on enclosure width mainly) will automatically
implement 4-6dB of BSC.

If the bass unit is 3dB or less efficient than the mid, it is still
worth doing and L-pad the mid-treble to suit the bass unit.

rgds, sreten.

http://zaphaudio.com/smalltest/ for FR88-EX details.
 
sreten said:
If you have a bass unit 4-6dB more efficient than a mid-treble, c/oing
it 1st order (series is better than parallel with real drivers) at the baffle
step frequency (depends on enclosure width mainly) will automatically
implement 4-6dB of BSC.

If the bass unit is 3dB or less efficient than the mid, it is still
worth doing and L-pad the mid-treble to suit the bass unit.

rgds, sreten.

http://zaphaudio.com/smalltest/ for FR88-EX details.
Click to expand...

So let me get this straight- If a woofer is, say, 92 db spl, and the full range is around 86-88 db spl, the baffle step will compensate for the difference by dropping the bass drivers spl 4-6 db? And make the crossover a 1st order at whatever frequency the baffle step takes effect?
 
crazy-in-az said:
So let me get this straight-
If a woofer is, say, 92 db spl, and the full range is around 86-88 db spl,
the baffle step will compensate for the difference by dropping the bass
drivers spl 4-6 db? And make the crossover a 1st order at whatever
frequency the baffle step takes effect?
Click to expand...

Hi,

In free space baffle step always drops bass SPL 6dB. Near wall say 4dB.
But what your saying is essentially correct. C/o first order (series) at
around the centre point, the 3dB point, of the BS effect will give you
an ~ flat response and more balanced bass to the mid and treble if
the bass is a 4 to 6dB higher sensitivity than mid / treble drivers.

A lot of people think all drivers should be the same sensitivity,
they are wrong, only true for each driver in parallel bass BBMT.

rgds, sreten.
 
sreten said:
A lot of people think all drivers should be the same sensitivity,
they are wrong, only true for each driver in parallel bass BBMT.

rgds, sreten.
Click to expand...


I always thought that, but I've been learning a lot from this.
So, let's say the woofer I was using was around 90-92 db spl, would these drivers work?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1062
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-819
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-352
 
Hi,

Taking the specs at face value (not always a good idea) TB
option 2 seems the best to me and will most likely work well.

rgds, sreten.
 
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