I had an idea to make a pair of 2 way speaker some two years ago and I suddenly came across a tread talking about KT88SE amp by Scott 17. He did mention that he had designed a 2 way speaker with the above drivers. Oh...I thought it was perfect fit to my desire since I have the Deltalite II 2510 in hand and I can easily switch them around. Scott 17 was so friendly and generous enough to provide all his design and details for making this speakers. Hey, it's easy enough for me since I almost have all the parts in hand, and I only have to rewind some coil to fit. But I had a personal reason to start this project late until couple months ago. I talked to Scott again and asked if there was any change on his design, I then started ordering the Ciare 1.38TW and some resistors.
Long story short, I have all the ply cut and assembled right after. See how it goes.....
Long story short, I have all the ply cut and assembled right after. See how it goes.....
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Hi,
I'm afraid to say that x/o design is very poor.
http://www.eminence.com/pdf/DeltaliteII_2510.pdf
It doesn't remotely handle the drivers huge 10dB
presence peak or any BSC needed for good balance.
Tweeter attenuation is nowhere near enough.
It appears to be around 2.2KHz 6ohm Linkwitz Riley 2nd order
electrical,with a bass zobel and tweeter impedance compensation.
Its a naive approach by someone not really knowing enough.
rgds, sreten.
I'm afraid to say that x/o design is very poor.
http://www.eminence.com/pdf/DeltaliteII_2510.pdf
It doesn't remotely handle the drivers huge 10dB
presence peak or any BSC needed for good balance.
Tweeter attenuation is nowhere near enough.
It appears to be around 2.2KHz 6ohm Linkwitz Riley 2nd order
electrical,with a bass zobel and tweeter impedance compensation.
Its a naive approach by someone not really knowing enough.
rgds, sreten.
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I agree it's difficult to tell. The tweeter pad appears to take care of the 103dB->97dB, LR as you pointed out. Q of the woofer filter looks lower, maybe -9dB at 2k or so?
The 'peak' on the official datasheet doesn't show enough information to say it isn't artificially inflated on the on-axis plot (WRT estimating power) by way of it being part of cone breakup, so it's plausible that the shown crossover has evolved to someone's taste.
Serten,
Great to have a good hand to chim in. Since I don't know nothing about speaker design. Would really love to know how I could make it better.
Albert
AllenB,
Thanks for the comments.
Appreciate if you could tell how I could make change to make it better.
Albert
Allen,
First of all I haven't said I didn't like it from start. I put my respect to Scott 17 for his generously provided me all info I'd need to make this possible. He again didn't say this speaker design is unbeatable, but he encouraged me to try since I have them in hand.
He has a big heart I'm sure for the reason that he also encourages me to float this project to the forum and wish if there are somebody could give comment and or advice to tweet it better. I'm old and know nothing about electronics, but I trust this forum for the reason that I have finished some good amplifiers with the helps from members at the forum over the years. I pay respect to all guys not only giving comment but also giving advice to help members like me to make something for fun/ enjoyment. I hope all experienced members would answer naive questions for not all members are electronic engineers. I want to learn even at my age, but have to have someone to guide me along.
I have this project finished and I have been listening to them for almost a week now. I'd give detail report after the first 100 hours. And of course this project will keep open for ideas and advice.
Regards
Albert
Hi,
A quick simulation based on manufacturer datasheets shows the speaker is better than feared. Give it a try and have fun!
Dissi,
Thanks so much for your simulation. They're singing for me at the moment and they sound good. I float this up for advice and see if someone would help make it better.
Thanks again
Albert
AllenB,
Thanks. You recommend to tilt the speakers to try. ..I'd try that but so far to my ear I don't find they are annoying me. They are 6 ft away from the back wall, almost 3ft from the side wall. My listening position is 18ft away from speakers and there is 13ft to the back wall. no treatment for all walls except carpet hanged at the back wall, floor is full carpet though.
Aside from that the fact that the large peak in the Deltas response has been handled it is as sreten says, BSC has not been addressed and the tweeter isn't attenuated enough. This is also a way too high xover point for things to work properly. You're going to have terrible off axis plots.
The delta is a 97dB driver, throw in 5dB of BSC and you're looking at a final end point sensitivity of 92dB. Lots of tweeters can actually meet this requirement, but the Delta needs a low xover point to work properly. You'd be better off using something like the Ciare PT 383 crossed over appropriately. Still if you're happy I guess that's all that matters. The tweeter/woofer mismatch aside, this would sound much better with BSC compensated for and with the tweeter level reduced.
The delta is a 97dB driver, throw in 5dB of BSC and you're looking at a final end point sensitivity of 92dB. Lots of tweeters can actually meet this requirement, but the Delta needs a low xover point to work properly. You'd be better off using something like the Ciare PT 383 crossed over appropriately. Still if you're happy I guess that's all that matters. The tweeter/woofer mismatch aside, this would sound much better with BSC compensated for and with the tweeter level reduced.
Thanks and I really don't mind anything above 90db. I have lots of power for them, but what if I keep the tweeter ? Do you think the crossover is appropriate ? Or I can tweet it better by changing parts ?
As I said I don't know designing speakers at all. So more specific details would be appreciate. BSC ==Baffle Step Compensation ? Where I could get the program, so I could learn more from here on.
Thanks again
Albert
The specific tweeter that you have currently has been designed around being very sensitive, this in turn has sacrificed its ability to play low. The delta is a large diameter driver and needs to be crossed over as low as possible to keep the directivity as attractive as possible. You can see how these two things do not match.
The tweeter was no doubt chosen for its high sensitivity figure to match the mid/bass, but after you've compensated for baffle step this is not required.
Really in a situation like this, that being a large diameter mid/bass + tweeter, you'd want to be using a wave guide loaded tweeter or compression driver in a suitable wave guide or horn. These would be chosen to give you a good directivity match and you'd cross over at an appropriate frequency to allow the two to match up.
For this design that isn't going to be possible and the best you can really do would be to use a sensitive dome tweeter, preferably a larger diameter one, that can comfortably cross over lower than your standard 1" dome. Due to the high sensitivity and diameter of the delta you also need a tweeter that isn't going to crumble at higher SPLs. There are quite a few 1" dome tweeters that you could theoretically cross over around 1200Hz or so but they would not be able to go particularly loud.
The larger diameter Ciare has high enough sensitivity to match the delta once baffle step has been compensated for and due to its larger diameter is better suited to lower crossover points.
SEAS also have the T35C-002, but it isn't cheap!
I check the web download the online culculater and have the following result for flowing out 5 db.
F3. 498.36hz
Lbsc. 1.3 mh
Rbsc. 3.9 ohm
Rz. 6.324 ohm
Cz. 10uf
I understand L/ Rbsc parallel and in series after the 0.9mh. R/Cz in series to parallel the woofer. Am I on the right track? But how can I lower the tweeter db. Do I just working on that 3 and 6 ohm?
Hi,
A quick simulation based on manufacturer datasheets shows the speaker is better than feared. Give it a try and have fun!
Exactly. Two others besides me and Albert have built the same design. Everyone that has heard them thinks they sound great.
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