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  • mortron
    replied
    Am still considering this project but haven't really committed to any drivers.

    The Neo 3 I will defer to another project down the road. I don't think it's a tweeter I want to learn on.

    The 8" Nomex HDS woofer is one I've been interested in for a while now so feel safe to say I am going to order a quad of them to play with. Whether they are used in this design or not, I dunno.

    So I guess I'm kind of starting over from scratch.

    The criteria now is:

    - a speaker that is less than 12" wide
    - drivers which will have low distortion and flexibility at XO point
    - passive XO - at least on MT if not all 3.
    - would like to get bass into the 30's if possible.

    Even a project like Pete Schumacher's towers here looked appealing given someone's recommendation of the 830874 PBB driver. Though his design uses different drivers, it made me wonder:

    http://techtalk.parts-express.com/fo...r-way?t=219069

    While im not set on using Peerless drivers without compromising, they are on sale here and some can be had for pretty good prices and feel this is an opportunity to build something that will be good quality and be worth keeping long. ​​​​​​


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  • mortron
    replied
    I don't have a mic yet. I was gonna order one from Cross Spectrum as it's calibrated. Just waiting on gift money.

    As for my crossover it's only a 24db slope with response control... Ashly XR2000. Nice for what it does but a Swiss Army knife it is not.

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  • rpb
    replied
    Originally posted by mortron View Post
    I hate this tweeter... Aspects of it I love, others I hate. They were a gift though, so I have em.

    Maybe I just say to hell with it and make a TMW.

    Or I pull up my pants and find a different tweeter.

    I have been quite busy and haven't had a chance to run any sims yet. I'd like to find a used windows PC so I can run progtamsa bit easier. Wine doesn't seem to do much for me, may have to try again. Mac's are great until you need a PC only program.
    Tell me about the active x-over you have. Can you do different slopes, and x-over points for woofer and mid.

    Also, how close to the wall do you plan to put the speakers, and how forward, or laid back, do you like your music?

    The baffle response I posted made me think that it might be hard to shave off 5 or 6dB. If you add a passive high-pass filter, and possibly some padding, I'm sure it will work.

    How soon could you make a test setup for the tweeter, and measure it?

    Leave a comment:


  • PWR RYD
    replied
    I do not think you will have a sensitivity issue using your Neo3PDR with a pair of 830-991 woofers in parallel. I just completed the crossover design and voicing of my project using a XT25TG and a pair of 830-991's. On a 6.75" wide baffle I still had to pad down the XT25TG over 3dB. Looking at the manufacturer's plots for the two tweeters it looks like the Neo3PDR is more sensitive. Grant it I am running my 830-991'a as mid-woofers so I have a full 6 dB of baffle step loss, whereas you will be crossing them over higher and have less baffle step loss to compensate for. Still I think there is plenty of sensitivity to spare. Here are the two manufacturers' plots:
    Attached Files

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  • mortron
    replied
    I hate this tweeter... Aspects of it I love, others I hate. They were a gift though, so I have em.

    Maybe I just say to hell with it and make a TMW.

    Or I pull up my pants and find a different tweeter.

    I have been quite busy and haven't had a chance to run any sims yet. I'd like to find a used windows PC so I can run progtamsa bit easier. Wine doesn't seem to do much for me, may have to try again. Mac's are great until you need a PC only program.

    Leave a comment:


  • rpb
    replied
    Originally posted by mortron View Post
    Was just concerned the mids would have too much output for the 90.5db tweeter.
    I just ran a sim on a 10 x 60 baffle, and you might indeed have an issue. Here's the sim. You could run the mids in series.

    Click image for larger version

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  • xmax
    replied
    I have always been extremely happy with many SB acoustics products, peerless is also good.
    For subs I would look very closely at the dayton RSS HF line. They perform about 90% as
    good as anything out there in my opinion.

    Leave a comment:


  • rpb
    replied
    Have you used software to simulate the baffle step?

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  • mortron
    replied
    Mine is dipole. That said, I'm going to make a stuffed chamber behind it isolated from mid. So I guess it will go back up?

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  • rpb
    replied
    Originally posted by mortron View Post
    Was just concerned the mids would have too much output for the 90.5db tweeter.
    The factory spec and graph for the Neo3PDR says it's 93dB sensitivity. The dipole is 90.5dB. I think 90dB would be sufficient anyway.

    Is this the correct data?

    https://www.parts-express.com/pedocs...ions-44576.pdf

    Leave a comment:


  • Dave Bullet
    replied
    Originally posted by mortron View Post
    Was just concerned the mids would have too much output for the 90.5db tweeter.
    I find the secret is starting with a reasonable BSC level and making sure you use the right sensitivity target of the woofer to work out overall system sensitvity.

    You may be able to play the tweeter without padding. It probably limits how low you can XO as you'll lose acoustic output.

    It depends on the target slope you are planning (or flat response). I did an excursion modeling spreadsheet that takes 3 drivers so you can work out which one will "xmax first". Can't find it now

    Leave a comment:


  • mortron
    replied
    Was just concerned the mids would have too much output for the 90.5db tweeter.

    Leave a comment:


  • rpb
    replied
    The mtm sensitiviy will be determined by the mid-ranges. So, after BSC, the sensitivity will be about 86dB. The tweeter will need to be padded to match. The level between mid-ranges, and woofers, is matched with the active x-over gain adjustments.

    Maybe I missed something else. Why are you concerned about the Neo3 sensitivity?

    Leave a comment:


  • mortron
    replied
    My bad Wolf... And the worst thing is that I know bettwr than to confuse them!

    Apologies.

    I am glad I started this thread, it has really helped with my research and where I need to shore up and what I may find a challenge as things progress.

    But yes... Neo 3PDR is 90.5db... so that may change things. For some reason I rhoughtit the other model with higher efficiency. These came from Danny at GR Research about 3-4 yrs ago.

    Leave a comment:


  • Wolf
    replied
    mortron, You're using efficiency and sensitivity interchangeably, and they are not the same thing. Efficiency is based on power at 1W, normally specified as a percentage. Sensitivity is based on a voltage of 2.83V, and normally specified as a decibel output level. Since drivers are voltage sensitive devices, and not power based, and everything can be based upon the 2.83V specification regardless of impedance rating, then sensitivity is what you should be using for output and simulations. The Neo3PDR has a sensitivity of 90.5dB. This is not it's efficiency.

    Best regards,
    Wolf

    Leave a comment:

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