Testing adding tweeters to the high end on the Amazings

[OldiesButGoodies]

I like the effect,  will not design it as a permanent change as I am planning a separate redesign of the baffles and bass drivers,  but this is fun in the mean time. Crossed over at 17.5Khz. 

IMG_2259 by JSifontes, on Flickr

IMG_2260 by JSifontes, on Flickr

IMG_2261 by JSifontes, on Flickr

 

OBG

[schwarcw]

That is a very high frequency, Mosquito tone range.  Can you hear it?

[MacGeek]

Last time I checked, 17.5khz is about where my hearing starts to roll off.  Of course, 16 to 20khz is only 1/3 octave anyway.

What are you plans for the driver/baffle redesign?

[OldiesButGoodies]

The 17.5K is the designed to number.  I put it there because the RTA is saying that the main ribbon drops off like the barrier reef at that point.  My 52 year old ears here them though.  I think I need to double check the tested value of the caps to ascertain the actual x-over point (but the taper is slow with just one cap,  so I am probably getting output from below 17.5). In fact,  I will just order decent caps and take it 2nd order. 

Come spring I will either:

• Strip the existing baffle and repaint it piano black with several coats of clear (it is scratched up),  add the dome super tweeters (or a Dayton ribbon, under evaluation) in a more elegant fashion (tough to do because I like the idea of just continuing the line source, keeps imaging tight, so may just repeat what I have in a  nicer finish) or
• Create a new design with an out board bass unit using hivi or JL drivers,  and build a rib tower baffle separately that incorporates the domes (or the Dayton ribbon,  or a pair on Infinity EMITs modified to have rear output - just use the front frame of a pair of non-working EMITs on the back)

Will see what I decide,  but at  any rate thoughtI would post my mad tweaks here to stir up activity in the forum.

:-)

OBG

[MacGeek]

Your part two seems to take you a fair way to just building a new speaker, which will allow you to maintain the integrity of the Amazings.

[Meles]

The 17.5K is the designed to number.  I put it there because the RTA is saying that the main ribbon drops off like the barrier reef at that point.  My 52 year old ears here them though.  I think I need to double check the tested value of the caps to ascertain the actual x-over point (but the taper is slow with just one cap,  so I am probably getting output from below 17.5). In fact,  I will just order decent caps and take it 2nd order. 

Come spring I will either:

• Strip the existing baffle and repaint it piano black with several coats of clear (it is scratched up),  add the dome super tweeters (or a Dayton ribbon, under evaluation) in a more elegant fashion (tough to do because I like the idea of just continuing the line source, keeps imaging tight, so may just repeat what I have in a  nicer finish) or
• Create a new design with an out board bass unit using hivi or JL drivers,  and build a rib tower baffle separately that incorporates the domes (or the Dayton ribbon,  or a pair on Infinity EMITs modified to have rear output - just use the front frame of a pair of non-working EMITs on the back)

Will see what I decide,  but at  any rate thoughtI would post my mad tweaks here to stir up activity in the forum.

:-)

OBG

Well, my Vandersteen 4a's are rated to 40khz. It definitely loses something when you disengage the super tweeter. My best guess is that with analog you have a medium that has extension into this range. With a proper super tweeter you will gain a more faithful reproduction of the waveforms of the original sound of the instruments. I would imagine that these waves interact with ones in the "audible" range.

I'd think you want a line source type tweeter in order to best match the dispersion characteristics of the Carver's ribbon. Line sources lose something like 3db per meter in the highs coming from the speaker. Those domes are going to be more like 6db per meter.

A friend of mine used to own these and now has Apogee Divas.

[Sir Thrift-a-Lot]

As a gigging bassist for around 25 years, I've spent a lot of time in crowded bars next to crash cymbals.   At 48 I roll off sharply at 14k.   I'll have to take your word that this mod is beneficial.

[bmwr75]

Wish I knew the frequency of the ringing in my ears?  It sounds really high to me and is nearly always present, but pretty low dB.   Have been seeing some new drug for tinnitus being advertised lately, should try it I guess.

[Sir Thrift-a-Lot]

I think I need to double check the tested value of the caps to ascertain the actual x-over point (but the taper is slow with just one cap,  so I am probably getting output from below 17.5).

Be sure too that you account for the impedance.   It looks like you have all three tweets in series, though it is hard to trace the wiring on the photo.   If you are using a standard 8 ohm chart, you are crossed much lower (or is it higher, I think it is lower) than you think you are (assuming all drivers are eight ohm).    An easy fix might be to add one more tweeter to each side and wire series/parallel.   

[schwarcw]

How about a hearing test for the old guys here (me included)  Look here!  http://music.ece.drexel.edu/hearingtest/

[schwarcw]

I could hear them all up to 19.5 KHz. and down to 35 with out subwoofer.

Post your results

[OldiesButGoodies]

15 -18.5 Khz using Skull Candy Ink'd 2 earbuds

[Sir Thrift-a-Lot]

Unfortunately that one doesn't work for me as I can't hear 16.5k.   This one has a sweep from zero to 20k.

http://onlinetonegenerator.com/hearingtest.html

[bearjew]

haha either my shitty $20 speakers at work don't work well, or my hearing literally shits the bed at 13k.  I'm fairly certain it's the speakers...  a little concerned now though; will check again when I'm home.

[OldiesButGoodies]

Just use earbuds - almost any earbud will go to 20K (unless it has been run through the dryer)...

Pepe