designing crossover för Thiel and Eton...

[woofes]

Hi!

This is my first post/thread here and I´m from

sweden!

I need help designing a crossover for:

Thiel C12 + C89T or
Thiel C12 + Eton 5-880/25 HEX

the kombination

Eton ER-4 AMT + C89T
Eton ER-4 AMT + Eton 5-880/25 HEX

is also interesting!

Anyone that has any experience in those ? Should I go

for a bigger midrange like the 7-372/32 HEX? For

bottom I use 10" from TC Sound.

/Andreas

[pinkmouse]

Moved to 'Speakers, where you may get a better response!

[CeramicMan]

I'd also consider an 11" Eton woofers for the bass as well, Or have you already purchased the 10" from TC Sounds? The Eton woofers appear to have the advantage of high break-up frequencies, which lets you use small, high quality midrange speakers. You should also consider the C23 Accuton tweeter as an alternative to the C12, because it has a flatter impedance curve ie: less mechanical ringing, and therefore the crossover should be easier to design. However it is debatable because the C12 has other benefits thanks to its slightly smaller cone, such as wider dispersion.

The C12 would a better choice if it's crossed over at a relatively high frequency like 4kHz or 5kHz to avoid its resonance peak by a good margin, and if you use a midrange that performs beyond those frequencies. I would probably use the C79 midrange also from Accuton, and it has ferrofluid . Because it is a true "midrange" speaker and not a "mid-woofer" it's only useful down to about 300Hz or so, and therefore the "11-581/50 HEX" Eton woofer would be a great match for it. In fact I think the top of the range Avalon loudspeakers use that very combination of speakers, or something very similar.

Have you considered the Excel series speakers from Seas? I think their 4.5" and 5" metal-cone speakers would be good options for the midrange, but probably with better bass performance. I think they would give a very rewarding sound if you can put notch filters in the crossover.

CM

[woofes]

I´ve been using those TC 10" for som years now and I would never change them for anything!!

The thing is that I use the Thiel C23 and Eton 7-372/32 HEX in my system now. But I´ve never been fully pleased with the sound, dont think it come loose the way I want. Thinks that it might have to do with the "bigger" cone area and the dispersion you mentioned. I have had this system for 5 years now and thinks it´s time to do somethin new again. A friend of mine is interested in buying my old stuff.

I just came across a filtersolution for Thiel C12 and Eton 5-880/25 HEX. What pos and cons might the smaller midrange have compared to my bigger Eton 7-372/32 HEX? Or should I stay in size and get the Eton 7-360/37 HEX instead?

You can see a picture of the system here..
http://www.diyaudio.com/forums/showt...286#post314286

[CeramicMan]

Your speakers look very good, but I think it's possible they could be suffering from the same problem that my speakers have. My speakers use the C2-94 7" midwoofer from Thiel & P, and the same C23 tweeter that your speakers use. For the bass I use a 12" mono subwoofer in a sealed box with equalization and a very steep crossover.

The problem may be that the midwoofer's box is too small. I'm not talking about "optimal" box sizes for bass frequencies, because who cares if the bass from the midwoofer is bad when there is a 10" or 12" woofer being used as well? According to Subwoofer Simulator the optimal size of a sealed box for the C2-94 midwoofer is about 4.2L, and about 6.7L for a ported box. 4.2L for a 7" woofer!?!? I made sealed boxes with about 15L each and a Qtc of about 0.42, and I still think they're too small. I'll explain why. Because the sound from the midwoofers and tweeters is so clean, reflections and resonances from inside the box are not masked and are easy to hear even though I used a lot of stuffing.

I found that both the C94 and the C23 have very good dispersion, good frequency response and the rest of it, but what bothers me is the sound that gets re-radiated from inside the box through the cone. I calculated that the surface area of the C94's cone = ~3.7% of the total hard surface area inside the box. This means that a large proportion of reflected sounds inside the box will reach the cone again before getting absorbed. For this I have 2 solutions:
1)Make an even bigger box with internal panels that reflect sound away from the midwoofer, or an infinitely big box.
2)Use a midwoofer with a smaller cone area.

By using a speaker with eg: half the cone area, the same-sized box could be almost twice as good because it's harder for the sound inside it to escape.

Perhaps there is a problem with existing crossover. What's the schematic for the crossover you currently use?

CM

[woofes]

Big thanks for your interesting thougts! Made me think!
Exactly like you mention I thought that the bass wasnt a big deal from a midrange woofer when I got the 2 10"! So I made a small enclosure with 3 layers of MDF , glued together with some sort of vibration damping glue. Dont hear to much through the cabinett, but never thought about the reflection through the woofer membrane!
I have the schematics somewhere, dont remenber much but it´s a 6dB/octave, dont remenber the cutoff freq.

Excuse my horrible english

[woofes]

here´s the xover schematics
http://www2.ostanback.com:8080/~woofes/temp/filter.jpg

[Stixx]

Hi,

Ceramic Man ist right in saying that the midwoof box might be too small, although reflection from inside the box could be adressed with an internal baffle of , let's say 45° angle AND using some stuffing.
What I also notice is that your loudspeakers with those very capable TC's are basically crammed in the corners of the room, very close to the wall! Not good for an even frequency response.

Then it would be interesting to know the schematics of your Xover: I think there is no way you can get away with a 6dB filter on the Eton's. I once had a DIY speaker using the 7/360-37 HEX (very good!) and a Dynaudio tweet, and it needed at least 6dB PLUS an LCR network to suppress the cone breakup resonance at around 4 kHz (I was able to measure with Clio). I had 1,4 mH plus 5.6uf, 0.22mH and 2R2 parallel, when I recall this correctly.

Good luck,
Oliver

[5th element]

He has a trap on the eton to address break up....

[Duck-Twacy]

Originally posted by CeramicMan
...
I found that both the C94 and the C23 have very good dispersion, good frequency response and the rest of it, but what bothers me is the sound that gets re-radiated from inside the box through the cone. I calculated that the surface area of the C94's cone = ~3.7% of the total hard surface area inside the box. This means that a large proportion of reflected sounds inside the box will reach the cone again before getting absorbed. For this I have 2 solutions:
1)Make an even bigger box with internal panels that reflect sound away from the midwoofer, or an infinitely big box.
2)Use a midwoofer with a smaller cone area.

...
CM

Maybe this is also an option?
3) Deflex acoustic panels
http://www.deflex.co.uk/cgi-bin/defl...deflexshop.cgi