new project - LCY Tweets and new Seas W18NX-001

[j.burtt]

I am getting the fever to build a new pair of speakers and am turning to the seasoned veterans of DIY for some input. I have read alot of good things about the LCY ribbon tweets on this site and am considering pairing them up with the new Seas W18NX-001 7" mid-bass. These will be built into a monitor and will sit on matching bass enclosures. I will also be looking for some suggestions on a single 10" or dual 8" woofers to cover the low end. I've thought about a 12", but I would be concerned about it keeping up with the speed of the other drivers. I will be using a Marchand 3-way electronic crossover and 2 Citation 7.1 amps to power the speakers. The amps are 130 watts x 4 or 450 watts x 2. I will use 1 amp in 4 channel mode for the mids and tweets and the other in 4 channel mode for dual 8" woofers, or Bridged to 450 watts x 2 for a single 10".

My initial thoughts would be to set the crossover at 24db/oct for the bass - midbass at 125hz - 150hz and 48db/oct for the midbass - tweet at 2Khz. It looks like the new W18NX-001 may have a little flatter frequency response than the W18EX 's did.

Questions:

1. What is the difference (sonically) between the LCY 110 and 130 ?

2. Dual 8"s or a single 10" woofer ( please give recommendations of Models and preference of vented or sealed based on personal experience).

3. Is there another midbass driver I should look at in this configuration ?

4. Any thoughts on crossover frequencies would be appreciated.

Here are the specs on the W18NX-001:

http://www.seas.no/PDF%20data%20exce...NX001E0042.pdf

[ShinOBIWAN]

2. Dual 8"s or a single 10" woofer ( please give recommendations of Models and preference of vented or sealed based on personal experience).

Definitely dual 8"s.

Reasons are:

Increased sensitivity when wired in parallel. ie. 2 x 88dB would be 94dB etc. You'll stuggle to get a decent low down 10 that can do that.

Radiating area of two 8's is equivalent to a single 12 meaning lower distortion and higher SPL's and/or more extension if using EQ.

Downside is that there isn't much price difference between 8 and 10" in an equivalent model line up. So costs will be higher.

3. Is there another midbass driver I should look at in this configuration ?

Why not push the woofers out a little more and turn it into a 3 way rather than the 2.5 way your suggesting.

You really need a high eff. midrange to suit the LCY rather than the 87.5dB W18NX.

Something from PHL, Precision Devices, Focal, Volt, JBL, Supravox, Audax, ATC etc. would suit the LCY better than the Seas I would have though.

4. Any thoughts on crossover frequencies would be appreciated.

Cross the LCY around 3Khz or above would look good to me.

The W18NX isn't a very good choice for the LCY - for starters your wasting the efficiency of the LCY and more importantly the W18NX has break up modes starting of at around 3Khz - which is the ideal XO point for the LCY.

I'd forget the W18NX if you go with LCY because the breakup will need much work to tame in the XO and still get a decent cross to the LCY.

[j.burtt]

I will look into the PHL's for mids. I have seen alot of praise on DIY about them. I had the same thoughts on the dual 8's instead of the larger single woofer. How far out do you think I should go on the woofer to midrange x-over ? Do you have any recommendations for the woofers ? I guess one of my bigger questions is vented or sealed ? I was a custom high end car audio installer years ago (early 90's) and developed a liking to a nice computer tuned ported enclosure. I read the negatives about port noise lately and don't want to have to make changes after the fact. I would rather do it right the first time. Some of what I read says to go to a rear firing port if you are going to build a vented enclosure. I would like to keep the back of the speakers about about 2 ft. off the wall and don't want to end up with boomy bass either.

****LOOKING FOR INPUT FROM THE RESIDENT BASSHEADS****

Yes, I know I was yelling. But it was in a good way

[hyl2369]

How about LCY110*1+ seas w15ly001*2 =MTM ?

I want to build a construction like this soon.

[catapult]

Since you're doing active crossovers and you have lots of power available, sensitivity isn't really an issue. The new Dayton Reference Series sub drivers are extremely low distortion -- possibly the best Mark K has tested -- and they can easily be crossed as high as 400 if necessary. Jonmarsh is planning an open baffle line array of them crossed to a big BG planar at 4-500Hz. This ain't your grampa's sub driver. A single 10" or 12" "HiFi" version should work quite nicely with a 7" mid.

http://www.partsexpress.com/webpage....=25&rak=DaySub

Oh, and about the mid, I'd stick with the Seas for the same reason. PHL has high sensitivity and a bit of a cult following but they don't test all that well for distortion.

[catapult]

Here's an example showing that a "subwoofer" driver can work quite well in a 3-way. Jim Salk uses a custom TC Sounds 10" in his Veracity HT3 along with a 7" mid and a ribbon. Everyone who has heard them says they sound great. And the Dayton RS is reportedly a bit cleaner in the midbass and low mids than the TC which is also excellent.

http://www.salksound.com/ht3.html



Edit: Dennis Murphy designed the passive crossover and I think the freqs are around 250-300 and 2500.