Hello,
I am building a system using Beyma 15MI100 (and some other components).
The pdf datasheet is showing VAS = 166liters and fs = 48Hz.
Loudspeakerdatabase.com is showing 264 litres / 37Hz.
Who is right? Can we trust loudspeakerdatabase.com in any way? What about their built-in "simulate this driver in a closed box" online feature (as I am going to use it in a closed box ~93liters)? Is loudspeakerdatabase any good site?
Also, in what way do the stock TSP parameters change, if the 15" has been used already ~200h at medium to high power in a BR cabinet?
(Please no comments here about the early rolloff, the low QTc and the high corner frequency. This is intended for the the midbass way. And gentle but sophisticated DSP crossover will align both 2 x 15" and 2 x 18" to have almost linear acoustic response down to 20Hz. The 2 x 18" will also be closed box, but bigger.
I will open another thread about the build as soon as I have designed the parameters right. There you can comment and critisize my calculations and intended system build. But first I need reliable TSP parameters for 15MI100.)
Thanks!
I am building a system using Beyma 15MI100 (and some other components).
The pdf datasheet is showing VAS = 166liters and fs = 48Hz.
Loudspeakerdatabase.com is showing 264 litres / 37Hz.
Who is right? Can we trust loudspeakerdatabase.com in any way? What about their built-in "simulate this driver in a closed box" online feature (as I am going to use it in a closed box ~93liters)? Is loudspeakerdatabase any good site?
Also, in what way do the stock TSP parameters change, if the 15" has been used already ~200h at medium to high power in a BR cabinet?
(Please no comments here about the early rolloff, the low QTc and the high corner frequency. This is intended for the the midbass way. And gentle but sophisticated DSP crossover will align both 2 x 15" and 2 x 18" to have almost linear acoustic response down to 20Hz. The 2 x 18" will also be closed box, but bigger.
I will open another thread about the build as soon as I have designed the parameters right. There you can comment and critisize my calculations and intended system build. But first I need reliable TSP parameters for 15MI100.)
Thanks!
I posted this here since 15MI100 is a PA component (although the use in closed box is typically not "PA").
Just checked datasheet, 37/264.
Anyway you will need to check your actual speakers TSP after some initial burning.
I'd trust the spec directly from the manufacturer but have you run simulations with both sets of specs? They may or may not produce much different results, if they are a lot different then one of them is probably wrong. But that said for a sealed midbass where you don't really care about the sub 100hz response there will be a wide range of enclosure sizes that essentially deliver the same results so go with the smallest cab you can get away with.
Not true: The enclosure is done. 93 liters. Built in the 90s. I care about the sub 100Hz since I want a VERY gentle filter (6dB) and almost no group delay. Goal is to have the 18 and 15s overlapping IN PHASE over some range. I am not going for highest SPL, so that is why I can use the 15 below 100Hz in closed box. Anyway - that is system discussion for later on, not what datasheet is right....
I get a "connection reset" error from Chrome trying to load that then Avast warns me of a phishing attempt if I attempt to reload, so frankly, I wouldn't trust it at all.
To be honest, I'm not sure why you'd be wanting to use a pdf from some random website with no affiliation to the manufacturer anyway?
Use the manufacturer's own site: Beyma 15MI100
Might have been a early draft, later corrected.
Look how the power compression graph overlaps its descriptive text for example - I don't think that would be something they'd release as definitive.
Look how the power compression graph overlaps its descriptive text for example - I don't think that would be something they'd release as definitive.
Probably yes.
Check error with Xmax value vs coil length and faceplate depth.
47 Hz version would be the clear midband driver, with very high sensitivity and great midband impact, which needs very low volume at order of ~20-25 liters.
But most manufacturers doesn't provide such a speakers in 15"calibre. So, i suggest they put a different weak suspension what result in 2x Vas and lower Fs.
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The other possibility is that the manufacturer did just change the design (or the method of measuring TS parameters) without changing the model name.
Not helpful, but whatever the cause, I'd still trust the spec's on the manufacturers current website over the other ones if you're buying new drivers.
The other specs might be more accurate if you bought second hand drivers, but it could be very hard to find out which version of the driver you were getting before buying it so I wouldn't recommend that.
Not helpful, but whatever the cause, I'd still trust the spec's on the manufacturers current website over the other ones if you're buying new drivers.
The other specs might be more accurate if you bought second hand drivers, but it could be very hard to find out which version of the driver you were getting before buying it so I wouldn't recommend that.
the parameter that varies over time is the suspension stiffness. fs is resulting together with the moving mass, Vas is resulting together with cone area. so try to vary the stiffness,let the system calculate the resulting fs and Vas and other parameters that are linked. the end result may not be so catastrophic.
Actually I bought that speakers in 2015. Put them in BR enclosure 91 liters, tuned to ~55Hz. Working great!
Current project is to build (rubber?) plugs for the ports, for both 15" and 18" boxes, and write a different DSP setup for lower SPL home audio listening down to 20Hz.
So I can have ultra-low infrabass home audio system AND high SPL outdoor party audio system Two in One!
Thread will follow.
Current project is to build (rubber?) plugs for the ports, for both 15" and 18" boxes, and write a different DSP setup for lower SPL home audio listening down to 20Hz.
So I can have ultra-low infrabass home audio system AND high SPL outdoor party audio system Two in One!
Thread will follow.
Probably no.
Those speakers Xmax only 4 mm and with such high Fs you can't achieve acceptable response at 20 Hz.
I said 2 x 18NLW9400 CB 152l plus 2 x 15MI100 CB 91l (acoustical crossover target is around 80 - 100Hz, still not decided, currently calculating the transfer functions with MathCAD.
91 liter will be too much even for both of them, not saying for each.
This is a high-performance midband driver, like 15MB650, doesn't spent it's midband potential for providing bass notes.
Say, i'ld try it in something order of 20-25 liters vented box tuned to 85 Hz and with active Xover 12 db/oct at same 85 Hz.
Doing so will allow you to pick mostly all of the power at the 200 Hz range, mighty and very fast kick, order of 103-105 dB/wt at the axis. Well-matched with something like 3"-4" coil compression driver. See for example RCF ART 735 or 745 models.
Again, both or each?
My suggestion ~80 liter per speaker, box tuned to ~40 Hz, active XO at 40 Hz 2nd order.
Build both, measure response and then align phase, doesn't think about frequency it will be choosed by phase matching procedure.
BesPav, I know the usual design rules. But here I am not shooting for SPL, but for 20Hz and as low group delay / phase distortion as possible. That is a completely different design approach, especially since the system IS already a ported PA system and I am now designing the "plugged ports" mode. I am now sitting in front of a MAthCAD sheet that tells me I will not even reach 110dB, if going for a 3dB rolloff of 20Hz undistorted, using both 18"s. As you can see in the opening post, I put this under PA, since the components are PA, not the application. It is more like home listening / home cinema. If you are really serious going for 20Hz, plus avoiding phase distortion, you must use shallow soft filters (or: in my case a MAthCAD trick of pure magic that will be presented soon in another thread, latest next week), you must not follow ANY established PA rule. And you are going to sacrifice MANY dB on the way to get there.
The new system is there:
https://www.diyaudio.com/forums/sub...b-ultra-low-phase-distortion.html#post6176817
https://www.diyaudio.com/forums/sub...b-ultra-low-phase-distortion.html#post6176817
The 15MI100 isn't a typical PA midwoofer and definitely not a subwoofer driver. Obviously, you could make it work in PA mid cabs, but there are better drivers for such applications.
It's an almost ideal driver for a classic 2 way BR cab. A more efficient upgrade to the - also excellent - SM115, and with a slightly cleaner midrange.
Both drivers are very good up to around 800Hz and (cheaper) alternatives to the well regarded FaitalPro drivers.
It's an almost ideal driver for a classic 2 way BR cab. A more efficient upgrade to the - also excellent - SM115, and with a slightly cleaner midrange.
Both drivers are very good up to around 800Hz and (cheaper) alternatives to the well regarded FaitalPro drivers.
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