How Treat Passively Peaky Fullrange Drivers

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FullRangeMan

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How Treat Passively Peaky Fullrange Drivers
« on: 18 Nov 2011, 07:53 pm »
This thread is about keep FullRange drivers crossoverless to listen its Harmonic Integrity, that is the best feature a FR can delivery to the music lover.
If you are a CrossOver lover you may be frustated here.

Some Full Ranges drivers had strong mid-treble response, to keep it crossoverless, is need some passive treatment to smother the high frequencies.
Of course passive, is a non electronic part, as inductor, capacitor, DSP etc.

1) First: around all the box corners, even the small ones, with a triangular or L shape profile of wood or MDF. Alternatively can be used that soft massa/dough of caulk, avoid plastic or metal parts.

2) Second: Paint matte black or dyeing with dye all walls inside the box, even the Baffle, it is not difficult with a spray can.

3) Stuffing all the fullrange magnet with 30 to 50mm black foam or dark blue or brown. Pressed wool 20-30mm also is good. You will need some glue. Please note, that foam begins to crumble/mill after some 10 years, so use a new quality sample of medium density. Avoid 10mm carpet or non shaggy rug.

4) Stuffing inside the box as recommended by the driver manufacturer or even more. If the box is BassReflex, stuffing the duct also, with dark foam, not the inside of the duct/flute of course, but the outside of the duct.

5) Foam will raise the bass response too, that is good, as I am a bass fan.

6) Toe-in cost no money and will reduce the treble and beef-up image and will decrease lateral reflections on the walls.

7) Just adding this imaging to this old thread, this is a blanket used in car hoods and is very useful to up the bass freq, if used in excess it will down the hi freq too, that may be a useful tool to peaky full range drivers.
Use the 10mm version, image show thinner 5mm.

Please Note: Foam and wool blanket use space in the internal volume of the box, the white Polyester blanket will not occupy space in the box litrage.

If you had a suggestion or a new trick, please fill free to post here to us.
Cheers
« Last Edit: 15 Oct 2017, 04:10 pm by FullRangeMan »

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #1 on: 18 Nov 2011, 08:06 pm »
This thread is about keep FullRange drivers crossoverless to listen its Harmonic Integrity, that is the best feature a FR can delivery to the music lover.
If you are a CrossOver lover you may be frustated here.

Some Full Ranges drivers had strong mid-treble response, to keep it crossoverless, is need some passive treatment to smother the high frequencies.
Of course passive, is a non electronic part, as inductor, capacitor, DSP etc.

1) First: around all the box corners, even the small ones, with a triangular or L shape profile of wood or MDF. Alternatively can be used that soft massa/dough of caulk, avoid plastic or metal parts.

2) Second: Paint matte black all walls inside the box, even the Baffle, it is not difficult with a spray can.

3) Stuffing all the fullrange magnet with 30 to 50mm black foam or dark blue or brown. Pressed wool 20-30mm also is good. You will need some glue. Please note, that foam begins to crumble/mill after some 10 years, so use a new quality sample of medium density. Avoid 10mm carpet or non shaggy rug.

4) Stuffing inside the box as recommended by the driver manufacturer or even more. If the box is BassReflex, stuffing the duct also, with dark foam, not the inside of the duct/flute of course, but the outside of the duct.

5) Foam will raise the bass response too, that is great, as I am a bass fan.

Please Note: Foam and wool blanket use space in the internal volume of the box, the white Polyester blanket will not occupy space in the box litrage.

If you had a suggestion or a new trick, please fill free to post here to us.
Cheers


After what I read, it appears that you are treating the enclosure and not the driver. If a raw driver has problems then the driver needs treatment too.

FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #2 on: 18 Nov 2011, 08:24 pm »

After what I read, it appears that you are treating the enclosure and not the driver. If a raw driver has problems then the driver needs treatment too.
Yes, Iam treat the enclousure(I will no listen the raw driver), it can be BassReflex or Sealed, obviously for horns or OB this treatment not work.
Iam unknow any raw driver treatment, unless the magnet stuffing(item 3). Do you would inform which you are referring??

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #3 on: 18 Nov 2011, 08:34 pm »
Yes, Iam treat the enclousure(I will no listen the raw driver), it can be BassReflex or Sealed, obviously for horns or OB this treatment not work.
Iam unknow any raw driver treatment, unless the magnet stuffing(item 3). Do you would inform which you are referring??

Ever hear of EnABL?

Sometimes cone problems can be treated with a coat of damping material. Something brushed on or sprayed on. Dammar (varnish) was all the rage a few years ago.

Baskets that are stamped or that ring can be damped too. Use modeling clay or self adhesive peel and stick type of damping sheets.

Wedging, bracing the entire motor assembly (back of the magnet) to the inside rear wall of the enclosure has benefits too. Shown to improve transients.

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #4 on: 18 Nov 2011, 11:17 pm »
Wouldn't a notch filter be less of a compromise than a handful of passive tweaks that may each have their own side effects?

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #5 on: 18 Nov 2011, 11:32 pm »
Wouldn't a notch filter be less of a compromise than a handful of passive tweaks that may each have their own side effects?

The word "capacitor" frightens a lot of "Full Rangers!"

I actually saw before and after frequency response graphs of an inexpensive paper cone driver treated with Dammar. Took the points off, muted all the sharp peaks, be it ever so slightly.

FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #6 on: 19 Nov 2011, 01:26 am »
Ever hear of EnABL?

Sometimes cone problems can be treated with a coat of damping material. Something brushed on or sprayed on. Dammar (varnish) was all the rage a few years ago.

Baskets that are stamped or that ring can be damped too. Use modeling clay or self adhesive peel and stick type of damping sheets.

Wedging, bracing the entire motor assembly (back of the magnet) to the inside rear wall of the enclosure has benefits too. Shown to improve transients.
Thanks for informing.  I suspect brace the magnet motor as used on Yamamoto OB lower the Fs.

FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #7 on: 19 Nov 2011, 03:58 am »
Another trick, Use different thicknesses of wood for less enclousure resonance:
BAFFLE = 30mm
BACK = 10 to 15mm
SIDES = 20mm

BenjaminWebber

Re: How Treat Passively Peaky Fullrange Drivers
« Reply #8 on: 19 Nov 2011, 06:46 am »
Hi,

I am new here.  Guess I will jump in, and try to make some friends, share what experience I have, and learn from others. 

I have built two pairs of speakers so far.  Both were Full Range Drivers.  The upper-end was always the thing I wanted to "properly" tame. 

My first pair was Voigt Pipes with Fostex FE166E drivers.  Getting the line length right was my first (and biggest) improvement.  I had originally made them to tall.  Once I shortened them by putting a flat piece of wood inside at the top, my bass increased!  The next thing was fiberglass insulation.  Cutting the wizzer cone out, and adding a wooden phase plug I made (by use to two tiny magnets) was also a worthwhile improvement. 

I did make a baffle step circuit, and would not have wanted to be without it for MANY moons.  Someone told me at takes about 3 years for those drivers to fully break in.  That seemed to be true.  Eventually, I removed the baffle step circuits, moved to speakers closer to the corners of my room, and got better sound.

By second pair of speakers was a BIB (folded horn) with a Fostex F208 sigma and T90A super tweeter.  Hanging a banner shaped piece of masonite (with the pointed end toward the floor) into to second chamber, helped. 

Eventually, I did put a 0.25mH coil in series with the 208's.  I later added a little more wire to the coil to hopefully bring it to about 0.3mH.  I knew I lost some definition in the bass, etc., but I didn't care.  It took the edge off, and I could listen and enjoy them much longer.

Once I added the inductance, I could either listen on axis more than before, or position the speakers further from the corners.  Here is my current dilemma.  I have a spot somewhat out into the room where I get the very fastest, most natural (but slightly anemic) bass, as well as overall dynamics and resolution, from top to bottom, and depth of image.  Or, I put them back tight into the corners, and loose some of what I have described (and gain much more power, but a slight bloating) in the bass.  But mostly, tight in the corners, is where the vocals sound the very most natural.  Not piercing.  It is like having two different pairs of speakers in one, depending on how I position them.

I am glad this subject has come up.  I do plan to keep these speakers a long time, if I ever replace them.  I hope someone can benefit from my experiences.  I am excited to study all that everyone else has experienced.  I have not tried Bud's EnAble process on a driver.  I was afraid I might screw up.  Guess I should try it on a driver I don't care about first.  Bud did once invite me to hear two identical speakers.  One EnAbled and one not.  I live several hours away, and haven't done it, though.     

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #9 on: 19 Nov 2011, 06:50 pm »
Another trick, Use different thicknesses of wood for less enclousure resonance:
BAFFLE = 30mm
BACK = 10 to 15mm
SIDES = 20mm


If you really want to attenuate enclosure wall resonances, double or triple the layers.
Constrained layers are best, but you end up with a very heavy back breaking enclosure.




FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #10 on: 19 Nov 2011, 10:00 pm »

If you really want to attenuate enclosure wall resonances, double or triple the layers.
Constrained layers are best, but you end up with a very heavy back breaking enclosure.
This is great to a strong, firm enclousure. If the walls are all same thickness the resonance are greater than, if the walls are variable thickness.
Same walls thickness = more resonances.
Variable wall thickness = less resonances.
This happen why the vibrations run inside the wood like a loop.

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #11 on: 19 Nov 2011, 10:05 pm »
This is great to a strong, firm enclousure. If the walls are all same thickness the resonance are greater than, if the walls are variable thickness.
Same walls thickness = more resonances.
Variable wall thickness = less resonances.

Fail.
Different wall thicknesses = Different wall resonance.  No guarantee of "less" resonance only a change in frequency.
Not something you can guess. The only way you'll know for sure is to use an accelerometer attached to the enclosure walls.

FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #12 on: 19 Nov 2011, 10:18 pm »
Fail.
Different wall thicknesses = Different wall resonance.  No guarantee of "less" resonance only a change in frequency.
Not something you can guess. The only way you'll know for sure is to use an accelerometer attached to the enclosure walls.
Interesting point of view, thanks.
A great speaker that use different wall thickness with success are some Avalon models.

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FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #14 on: 19 Nov 2011, 10:39 pm »
Chladni plate/patterns.

http://www.youtube.com/watch?v=Sz1AuS-qA1c&feature=related
Hey this is a tweeter burn machine.    What is Chladni ??

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #15 on: 19 Nov 2011, 11:32 pm »

FullRangeMan

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FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #17 on: 20 Nov 2011, 04:40 pm »
Another economic tip:  Use 3 feet(not 4) to support the enclousure on the floor or stand.

FullRangeMan

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #18 on: 20 Nov 2011, 11:56 pm »
A great tip from ERIKB1971:  Make random craters inside the enclosure as the image below.

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Re: How Treat Passively Peaky Fullrange Drivers
« Reply #19 on: 21 Nov 2011, 01:31 am »
A great tip from ERIKB1971:  Make random craters inside the enclosure as the image below.

A lot of hard work . . . .

An even easier way would be to install acoustical ceiling tile inside the enclosure.