B&C 8NDL51 tweeter match?

[mayhem13]

I'm currently building 2 dual 10" sealed subs self powered at 500w for bookshelf bases for high efficiency 2 way. I have four B&C 8's and was originally going to do MTM but decided to save 2 drivers for MTM center channel. Any good tweeter matches come to mind in the high efficiency dome catagory. I plan on a sealed design passively crossed and crossed to the subs at 150hz. I'm also going to need some x-over help when the time comes.

I was thinking to load the tweeter into a modified waveguide to cross lower to the woofer. Most importantly i guess is does anyone see any inherent flaws with this whole setup? Thanx in advance !

[cowanaudio]

G'day mayhem

I'm currently playing with a system that uses a pair of the B&C's in an MTM with a BMS 4550 mounted on an 18Sound XT1086 horn. This system shows a lot of promise. It would be a waste of such a good mid/bass driver if you used a conventional tweeter for the top end. I've used a lot of excellent tweeters before and have not found one that can match the dynamics of these mid bass drivers. Look for a good compression driver/horn instead. The BMS, B&C and 18 Sound compression drivers are all highly regarded.

Cheers

William Cowan

[Saurav]

And, the 18sound XT1086 and the DDS ENG 1-90 Pro appear to be the most well-regarded waveguides. Search the forum, there are several threads discussing multiple combinations of these compression drivers and waveguides.

https://www.htguide.com/forum/showthread.php?t=29988

https://www.htguide.com/forum/showthread.php?t=19368

https://www.htguide.com/forum/showthread.php?t=20386

[mayhem13]

Thanx guys. I was looking to take the approach of Hi-Fi-high efficiency so hence the fear of the compression driver. I was hoping the boost in efficiency from the WG would be enough to keep up with the B&C in a TM design but i think i'll try a 1" compression and see how it goes. Any experience with Radian drivers ?

[ThomasW]

I've researched the Radian drivers, and unfortunately there's not much posted about them. What little that's posted is generally positive.

It's likely I'll be building a system using the Radian 465PB, since it looks to be the best choice for the 800Hz XO point I want to use.

If you're ok with a higher XO point consider the BMS 4540ND.

[Mark Seaton]

Thanx guys. I was looking to take the approach of Hi-Fi-high efficiency so hence the fear of the compression driver. I was hoping the boost in efficiency from the WG would be enough to keep up with the B&C in a TM design but i think i'll try a 1" compression and see how it goes. Any experience with Radian drivers ?

If you are doing a 2 way using a single 8NDL51, you may want to also do a reality check with your design as to what sort of sensitivity you will actually have. Above 300-500Hz the sensitivity should be high, but what is your target response as measured in the air, and what sort of sensitivity will you have near 100Hz. If you are doing this actively, then there may be much more justification of a compression driver, but in the interest of less complicated crossover design, I wouldn't rule out some 90-94dB dome tweeters. Where the compression drivers will have a real advantage is the output and pattern control in the 1-3kHz range, of course putting a conventional tweeter on a waveguide of some form can greatly help with the 1-5kHz output capability and sensitivity, and might do the trick.

Be sure to evaluate what you really need before you limit your options.

[augerpro]

Inline with Mark's comments I think something like the Peerless 810921 would easily cross to the 8NDL51, especially after some BSC is applied. I'm going to see if the 810921 can be successfully mated to the MCM waveguide, which would make mating it to a pro driver easier.

Are you making all of these as 2 way's with 10" subs, or 3 ways using the sub underneath bass bin style? What crossover point are you looking to do? In other words, how much, if any, BSC are you going to apply to the 8NDL51?

Also the B&C DE10 and the ME10 horn are well regarded for the price.

[mayhem13]

As a two way design, i'm thinking sealed and crossed at 120-130hz to the powered subs. I was hoping to cross the tweeter at 1400hz to a Morel MDT-30 mounted in the MCM waveguide. Given the 1.38 inch dome i will have to modify the guide more shallow than Zaph so i'm expecting to see a +3-4 db gain between 1-6 hz. Given then power handling and high efficiency, dynamics should be outstanding for such a compact design. I really don't want to actively cross these. Although the Behringer Ultra offers some nice features and convienience, there will be a cost and that's the price of audio in the digital domain. For HT i'm sure it would be fine but for critical music listening if i can do without added digital circuitry......

[Mark Seaton]

Moving the crossover to 120Hz+ gets you further up the baffle loss, and depending on your philosophies on box size, crossover, and impedance, you could end up with a system that is 92-95dB @ 1W/1m very easily. A waveguide on a tweeter should help with a lower crossover which will be desired with the 8" woofer, and the higher output this driver is capable of. You can dump a good deal of power into it above 80-120Hz without excursion problems.

[mayhem13]

Thanx for the tips Mark. I'll work up some box sketches soon and post. I'll start with 10 Liters stuffed and sealed. I bought 4 of the waveguides for modding. I'll mount the guide in the baffle and route for the driver flush mounted as much into the guide as possible without interfering with the taper too much-i figure about .5 inches. This should be a good starting point. I should know fairly quickly if beaming from the B&C is going to be an issue. I've read that small strips of foam mounted on the baffle vertically on either side of the driver helps alot-any comments?