DIY 3 way main speaker with 15" drivers?? - Page 3

Penn,

Understandable about the cost of the tweeters. In the early discussions about my design the “Fountek NeoCD2.0 ribbon tweeter” was discussed as an alternative. I also believe those may be the ones Thy is referring to. They are 126 a piece at Madisound.

Lambda TD10 (h,x) = 239.00
Audax PR170M0 = 83.30
Fountek NeoCD2.0 = 126.00
---------------------------
Driver total = 448.30

You could certainly use a different mid or even go with a high quality dome tweeter. It's your speaker, so it's totally up to you.

...... nuke

Penn,

Since you felt the price was acceptable for the design John had started I would suggest dropping him a line concerning them. From the looks of the dimensions of the cabinets they would appear to be a close fit to where you want them to go. If he continues to make these happen it would remove the need to try and produce a speaker from scratch. From what I gathered he had a lot of the process completed but started getting swamped with orders. Maybe he has had a little lull where he can finish the design.

Here is John's AVS username:
John_E_Janowitz

Hi Everyone,

Guess there is quite a bit to cover, but I'll do my best. Regarding the design with the pair of TD10M's and the NeoPro5i ribbon, I did spend a couple days measuring and designing the preliminary xover. The difficulty with this design vs others is simply that the ribbon tweeter can't be faced upwards. It sags. So to get good measurements with no reflections means putting the speaker up in the air. We ended up getting the tweeter approximately 10ft off the ground so I could get enough distance to gate out the floor and ceiling reflections in the gym I borrowed at church for 2 days. The TD10M does have a sharp peak of 5dB or so about 2500hz. The NeoPro5i has a peak about equal in magnitude at about 1200Hz. My intended Xover region was in the range of 1800-2000hz. Ideally each of the peaks needs a notch filter for the crossover to become more simple if doing it passively. I didn't have much time in the gym though, but using 3rd and 4th order filters you can modify the Q of the filters to somewhat take care of these peaks. That is what the initial Xover does and it works pretty well. If someone wanted to do it actively you'd just need one band of EQ for each of the peaks and things are quite simple after that. My hope was to play around a little more with the cabinet up on the forklift outside. However it seems to have been raining of ridiculously windy for weeks now.

That said, some people feel that the SPL capabilities still may not be high enough with that system. Levels of 120db+ continuous at 1m are extremely high, but who am I to tell someone they can't have more if they want it? The limiting factor is really the tweeter on the low end. While drivers like the TD12M's or TD15M's will play higher, they do beam more as well at these higher frequencies. The addition of a midrange driver is really the key to unlocking more of the potential from the woofers and tweeter. The difficulty is in finding a midrange that is really ideal and something that will sound as good as the TD drivers covering that range. It's an issue we are aware of and have some things coming down the road for that but it will likely be 3-6-12mos to make it a reality.

In the meantime there are some options to look at. The first one that comes to mind is the 18sound 6ND410. It has a 1w/1m sensitivity of 97.9dB which actually matches the real sensitivity of the NeoPro5i almost identically. Mark has a pair of these and says they are quite nice. So, one of these next to the NeoPro5i and then the pair of TD10M's or even TD12X's would really be an SPL monster.

Then at that point we get into the range where we can start looking at a 1" compression driver on the 18sound XT120 horn as well but that would require multiple midrange drivers and multiple TD12M's to fully take advantage. Personally I greatly prefer the ribbons to the compression driver option. Ah, so many options. The hard part is in coming up with something to make the majority of everyone happy.

Also on a slightly lower cost, lower output version a single TD12M with the 6ND410 and the NeoCd2.0M could be an option as well. RAAL ribbons could be substituted for probably the ultimate in sound, but slightly lower output version than the NeoPro5i.

There are multiple other options that could be thrown in for the midrange. The PHL's, Audax, B&C's, etc. could all be options, but it's looking like the 6ND410 is the best option until we can get some 6" and 8" drivers worked up here.

So here is my initial thought of what to offer. Give me your thoughts and suggestions. The MTM using pair of TD10M's and NeoPro5i as planned before as I already have a few applications for it.

Then a larger version stepping up to the TD12X's and adding the 6ND410mid.

I think as a third final option to save some cost we could look at a single TD12X, the 6ND410 mid and the NeoCd2.0M.

penngray, for your application specifically i think the third option would work as it would fit your left and right and be more along the lines of your initial request. For the center channel I need to do some thinking yet. You could easily use the same mid and tweeter, but with only 9" H we need to figure out something for the woofer section. If only you had 2" more height to work with it would be simple. Let me do a little thinking on that yet.

John

For the center I would stick with the single 6nd410. The MTM center channel on it's side is by far the worst option out there. You take a vertically well controlled speaker and turn it sideways and now you have a horizontally well controlled speaker. Now your midrange is very directional down the middle of the room but not at the sides. The only time you can do this successfully is with a very low Xover frequency to the drivers on the sides. Like in Mark's Catalysts the 8" coax allows the 12" drivers xover to be low enough to not have this beaming effect. Most people think the center having symmetry is the ideal situation, however it isn't required.

How high can you go in the center? That will determine the options. If you can get 14" you could simply do the TD12 next to the 6" with the ribbon above it. If you can't go that high, a TD10 would work in about 12" total height with the 6" and ribbon next to them.


Off axis horizontally is great. It's the vertical that is well controlled after about 5 degrees off axis up or down. In reality for any kind of typical listening though you have probably about 10degrees to work with. It's not going to sound bad anyway as it is a very smooth rolloff past that point, it's just going to decrease quite rapidly above about 7KHz or so. IMO this is a huge benefit as you aren't getting the floor and ceiling reflections. How far is your listening position from where the speakers will be mounted? At about 2M away you have about 22-23" of height before the tweeter will begin to roll off at all. This is only at 5degrees and at 10 degrees you have about 34" to work with. At a 2m distance though, 22-23" of height is more than enough to cover any height person sitting on a chair, slouching, even laying down on a couch. The only trick is to aim the tweeter in the center channel to cover the correct area. Horizontally you'll easily be able to cover the whole room.


John

Penn,

The PHL 1120’s are 160’ish
http://estore.websitepros.com/173675...gory=PHL+AUDIO

The TD12H are 250 a piece (I believe) but I think John takes off 25 if you buy multiples.

RE: BnC 6PEV13, that is a viable option. I was picking drivers on the cheap and with a Lambda woofer, the Audax is likely the cheapest mid that will work well, but there could be an other.

PS, you wont really find bad reviews on PE. Anything good gets put on the comments, anything negative, somehow doesn't make it. There was something on that in the "measuring amps" thread.

The B&C 6PEV13 could be an option. The reason I wouldn't consider it is that it's only listed in the product archives on the B&C site so I believe it has been discontinued. The B&C 6MD38 could be an option at $92 each.
http://www.bcspeakers.com/index.php?...e=2&prodotto=1

I guess it depends on what people would like to do. If you are planning to do an active system and set everything up yourself, you could easily go with any driver of your choice. My initial thought is to come to a basic consensus on which drivers to use to offer more of a long range available kit with xover plans, etc and then also offer the same as a fully assembled and tested system. This would mean that product availability has to be one of the issues considered as well. Mark has some of the 18Sound 6ND410's and has given me good feedback, so that was my initial thought. If we decide on that driver for the completed systems, we may also be able to work out something to provide them for the kits. I'll have to check on that this week and the technicality as to whether a full kit is ok to sell under our OEM status with 18sound.

John

Passive is easier and costs less if you're following a proven recipe in it's 3rd or 4th revision/incarnation. If you're up for some experimentation however, this is much less convinient...

Active will require separate amps, and your receiver will have to have line level outputs. If you were doing 2-ways you could get away with a stereo amp per speaker after the xover box. You're gunning for 3-ways though. Basically you end up "bi-amping" (or in your case tri-amping?) which is also good stuff, but for someone like me a bit prohibitive because it's costly.

Gotta pay to play, as always

Make it down to South Florida and come visit me to see examples of both! With an explanation of the trials and tribulations of both!

Go active crossover unless you're absolutely certain of a crossover design and will not be tweaking it at all. I've played around with crossover points and such on my speakers constantly since I got them. For example, I had my speakers cranked high one day and cooked my midranges (dual M4Ns on each side which are only something like 15W each) so I raised the woof/mid crossover a bit and problem solved.

You can get a Behringer CX3400 for under $100 most of the time. That's what I used before I went to the DCX2496 and it was great for the money. (I got it for ~$50 on Ebay.) A DCX2496 is great, too. Much more flexible but also more money.

...... nuke

Ask ssabripo what he thought of my system with a DCX2496 in it.

DCX2496 adds no audible noise, though it did give me a ground loop problem (as did the DEQ2496). Strange considering I have everything plugged into the same power strip.... Got cheater plugs on the Behringer stuff for now and all is good.

I use RCA to XLR cables out of my Pioneer Elite 91 into the DEQ, then digital from the DEQ to the DCX, then XLR to RCA cables out to my Emotiva LPA-1. I have no issues with voltage. The adaptor cables work just fine.