12" Bass (project cancelled)
Printed From: Speakerplans.com
Category: Plans
Forum Name: Ported Enclosures
Forum Description: Post all your reflex and bandpass and 'other' boxes with holes in stuff here...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=98582
Printed Date: 27 March 2026 at 4:06am
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com
Topic: 12" Bass (project cancelled)
Posted By: Speaker Sol
Subject: 12" Bass (project cancelled)
Date Posted: 22 May 2017 at 7:32pm
|
Edit. On second thoughts not worth pursuing. Hi, Some background as to why I am trying to do this is at the end of the post if you are interested. I have a pair of BMS 12n620 I would like to use in a bass bin. I'm using WinISD Pro Alpha. Some Questions. Cone Excursion: 1) Is shown as peak to peak (both ways) or Peak (one way)? 2) How does impedance influence cone excursion, it appears that there is an impedance spike quite close to my cone excursion peak. I am wondering how does this affect the cone excursion, it's unlikely I will be putting 500w peaks into the driver if the impedance at 60hz is 25ohms. Or does WinISD already take this into account? Or possibly I am misunderstanding something fundamental? Cabinet Goals Smallish box that will hit 40hz to 100hz and @ ~106dB or more. Size 60Ltr Tuning 39Hz WinISD Results Magnitude + Filter Settings.  Cone Excursion 500W  Impedance (Does this seem right?)  Maximum SPL  So I am up for just building this and seeing what happens, but thought I would ask first as it's likely I could have misunderstood or made silly mistakes. Any help is welcome. Thanks. Back Ground I have a pair of double 12" + 1" cabs I am not using and have not been able to sell. Since my cubo 12s can easily outpace the little 2x 8" community tops I got for them I am planning to use the drivers out of the double 12" mid tops to build: 1 pair of 12+1 tops for the cubo 12s 1 pair of 12" bass bins for the Community tops. So I know the cones are not ideal for a bass bin, but if I can get a result good enough for home use and BBQs then at least I am doing something useful with them and learning (hopefully). |
Replies:
Posted By: gen0me
Date Posted: 22 May 2017 at 7:51pm
| First check speaker parameters. Winding deepth 19mm, magnet gap deepth 8mm and Xmax 3.5 dont calculate. No matter how. http://www.bmsspeakers.com/fileadmin/bms-data/product_data_2011/cones_neodymium/bms_12n620_2011-04_neodymium_low_midrange_driver.pdf" rel="nofollow - http://www.bmsspeakers.com/fileadmin/bms-data/product_data_2011/cones_neodymium/bms_12n620_2011-04_neodymium_low_midrange_driver.pdf |
Posted By: Speaker Sol
Date Posted: 22 May 2017 at 7:56pm
|
Intersting. http://www.bmsspeakers.com/index.php?id=12n620_thiele-small" rel="nofollow - http://www.bmsspeakers.com/index.php?id=12n620_thiele-small Web Site States X-Max of 5.5mm+/- |
Posted By: Speaker Sol
Date Posted: 22 May 2017 at 8:01pm
|
Xmax = (Voice Coil Length - Height of the Magnetic Gap) / 2. Xmax = (19 - 8) / 2 Xmax = 5.5 Correct?
|
Posted By: Speaker Sol
Date Posted: 22 May 2017 at 8:04pm
| Is it possible that at one time they felt that above 3.5mm the distortion was such that they considered the xmax to be 3.5mm. But at a later date switched to just calculating xmax regardless of distortion levels? |
Posted By: bass*en*mass
Date Posted: 22 May 2017 at 8:50pm
|
12n620s are not really bass bin drivers are they?! why waste time and money on something that could be done better with dedicated drivers? 5.5mm linear xmax seems spot on imo though.. good for low tuned "fullrange tops" but not on bass duty |
Posted By: Speaker Sol
Date Posted: 22 May 2017 at 8:56pm
Explanation as to why im thinking of doing this is at the end of my first post. If the general consensus is its not worth the effort, I will put them on a shelf unit someone eants to buy them off me... |
bass*en*mass wrote:Posted By: gen0me
Date Posted: 22 May 2017 at 10:46pm
|
There cannot be distortion before vc leaves the gap. Where from? You could add like italians do 1/4 gap than it makes 7.5mm... |
Posted By: Speaker Sol
Date Posted: 22 May 2017 at 11:50pm
|
Okay. I think this is bad idea. Will focus on the mid-top And sell the spare two drivers / make a second pair of tops. Thanks. |