Okay so B&W make excellent quality drivers and the same basic approach is used in their lower range models compared to their top line. Some things change, such as magnet material, cone material, basket design etc, so cosmetically they look very different, but in terms of build quality and performance? They are all using similar sized voice coils, built on similar former materials, with similar epoxies and motor/pole geometries.
You can see Goran's measurements from a basic B&W driver at audioexcite. This has class leading harmonic distortion and all basic design featues you'd expect to see on top of the line drive units.
There's nothing inherently wrong with the B&W drivers what's wrong is that you chose the wrong ones.
The midranges that you're using are of course actually mid/bass drivers with low sensitivity. If you'd gone for the neodymium version of the midrange from the 800 series, and crossed them with a steep filter at 400Hz, especially in an MTM, I think your mid range drivers would be fine. They aren't pro drivers but they do have very high sensitivity for hifi drivers. 95+dB. This is as close to pro as you'll get without actually being pro.
The tweeters are another matter entirely. If you're using a dome tweeter you absolutely need a high sensitivity design, like a Bliesma 95dB dome, and it will need to be in a waveguide. This will push the sensitivity up to 100dB around the crossover point, which is usually the region where a tweeter will be handing the most power. Or just put a compression driver in the waveguide and be done with it.
When you were testing your tweeters for SPL and they blew I'm not surprised. You were most likely doing this with sine waves. Dome tweeter voice coils only handle 5-20 watts of continuous power. Where they get their power ratings is because they are rated using noise stimuli and bandwidth limited. A sine wave signal, attempting to push 120+dB out of a dome tweeter, will fry it in seconds. Music peaks of 120dB in the treble are a different matter entirely due to the transient nature of music and the general downward slope of high frequency energy present in music.
Testing power handling of a voice coil, with it hung in free air, is not particularly useful. When the voice coil is in the speaker it is situated very close to the metal within the magnetic gap. This metal wicks the heat out of the voice coil and provides significant cooling. Slowly the metal and magnet heats up. If you're running high power then several things can happen.
First you completely overload the voice coil beyond the ability of the motor to wick the heat away and the driver fails within seconds to a minute. This is what happened to your tweeters when you were SPL testing them.
Second you're driving the system hard but not like the above. The voice coils start getting hot but the motor metal is able to wick the heat away to prevent immediate over heating. As time goes on the metal starts to heat up but due to its thermal mass this takes a while. As the metal starts getting hotter the voice coils also start running hotter and after listening for a while the voice coils get too hot and the drivers fail.
Neodymium drivers fail faster than ferrite ones in the second scenario because they have much less thermal mass.
Drivers that are designed for very high power handling usually have heat sinks to cool the motor metal/magnets and often employ air channels within the motor to force air the speaker moves, during operation, through the channels to improve cooling. Hifi drivers don't tend to come with any of these unless they have tiny neo magnets.
At a minimum you need to use the high sensitivity B&W FST drivers if you want to keep using hifi drivers. And you need to get the tweeters into a waveguide. Preferably use a hifi tweeter with big ferrite magnets to increase the thermal mass and perhaps strap heatsinks to it. The Morel ET338 springs to mind. Although no 25mm dome tweeter has power handling beyond a few tens of watts on anything except very short transients.
Still I'd use a proper pro midrange + compression driver to guarantee anything. The mid is going to be bandwidth limited by it's very design. Don't expect it to go below 400-500Hz if you're using a 6-7" device. It needs to be 95-100dB.
You can see Goran's measurements from a basic B&W driver at audioexcite. This has class leading harmonic distortion and all basic design featues you'd expect to see on top of the line drive units.
There's nothing inherently wrong with the B&W drivers what's wrong is that you chose the wrong ones.
The midranges that you're using are of course actually mid/bass drivers with low sensitivity. If you'd gone for the neodymium version of the midrange from the 800 series, and crossed them with a steep filter at 400Hz, especially in an MTM, I think your mid range drivers would be fine. They aren't pro drivers but they do have very high sensitivity for hifi drivers. 95+dB. This is as close to pro as you'll get without actually being pro.
The tweeters are another matter entirely. If you're using a dome tweeter you absolutely need a high sensitivity design, like a Bliesma 95dB dome, and it will need to be in a waveguide. This will push the sensitivity up to 100dB around the crossover point, which is usually the region where a tweeter will be handing the most power. Or just put a compression driver in the waveguide and be done with it.
When you were testing your tweeters for SPL and they blew I'm not surprised. You were most likely doing this with sine waves. Dome tweeter voice coils only handle 5-20 watts of continuous power. Where they get their power ratings is because they are rated using noise stimuli and bandwidth limited. A sine wave signal, attempting to push 120+dB out of a dome tweeter, will fry it in seconds. Music peaks of 120dB in the treble are a different matter entirely due to the transient nature of music and the general downward slope of high frequency energy present in music.
Testing power handling of a voice coil, with it hung in free air, is not particularly useful. When the voice coil is in the speaker it is situated very close to the metal within the magnetic gap. This metal wicks the heat out of the voice coil and provides significant cooling. Slowly the metal and magnet heats up. If you're running high power then several things can happen.
First you completely overload the voice coil beyond the ability of the motor to wick the heat away and the driver fails within seconds to a minute. This is what happened to your tweeters when you were SPL testing them.
Second you're driving the system hard but not like the above. The voice coils start getting hot but the motor metal is able to wick the heat away to prevent immediate over heating. As time goes on the metal starts to heat up but due to its thermal mass this takes a while. As the metal starts getting hotter the voice coils also start running hotter and after listening for a while the voice coils get too hot and the drivers fail.
Neodymium drivers fail faster than ferrite ones in the second scenario because they have much less thermal mass.
Drivers that are designed for very high power handling usually have heat sinks to cool the motor metal/magnets and often employ air channels within the motor to force air the speaker moves, during operation, through the channels to improve cooling. Hifi drivers don't tend to come with any of these unless they have tiny neo magnets.
At a minimum you need to use the high sensitivity B&W FST drivers if you want to keep using hifi drivers. And you need to get the tweeters into a waveguide. Preferably use a hifi tweeter with big ferrite magnets to increase the thermal mass and perhaps strap heatsinks to it. The Morel ET338 springs to mind. Although no 25mm dome tweeter has power handling beyond a few tens of watts on anything except very short transients.
Still I'd use a proper pro midrange + compression driver to guarantee anything. The mid is going to be bandwidth limited by it's very design. Don't expect it to go below 400-500Hz if you're using a 6-7" device. It needs to be 95-100dB.
Sorry forgot the last ones: a)Yes for sure b) most likely c)maybe true but in Norway it is considered important .. I think you are trying to annoy or pull my leg here.. attaches is a picture of some of the photo or video uploaded as reply to serious and good questions other readers had pls have a look
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HELP neded: I can get hold of 4 JBL M202A tweeters coming from JBL speaker M360, never heard of or touched neither.... , but they seems fine specs vise... see attached (hole speaker), and seem (like many has suggested more rugged. ) asking price is 150 Euro for the 4, and they are old, but never used, still in box. Looks like brand new to me. It looks like old bullet tweeter , in plastic, but it has titanium diaphragm capable of getting rid of heat. I understand they will not sound as good, as todays B&W but is it an decent piece of equipment and a okay solution????? (until I can afford those huge planar PA tweeters (at 300 Euro each) that was suggested earlier. and I need 4+1 of each driver type)
This is just excellent info!!! (Things I was not aware of.. so several "ah ha.. of course, now it make sense") but basically it made me understand why my current design failed and how to prevent it in MkII. I really appreciate that you took the time to make this post. Ref the Morels great yes, but is it enough? Maybe its safest for look for a compression driver /horn in one unit? Something like Visaton TL 16 H but with half the resonance frequency, meant for 2500Hz instead of 6000.
What ever this speaker need, my current middrives works fine to 5k/96 dB/oct or higher slope, but I need high spl. No (but could as just be): I use APO equalizer to test and it allows for absolutely everything in 8 channels just by writing small script like : Filter 1: ON PK Fc 50 Hz Gain -3.0 dB Q 10.00 and when done with all corrections, you can leave it like that but I like to create the filter in rephase/rew using my measurements of the impulse response, then I use APO or FOOBAR to process the convolution wave format filter. I have done this a long time but not including corrections in the time domain, only frequency, so this is a process of learning at the moment. Yes I can limit and compress and use any plug in from recording equiåment
No. No. No.
Do you have any clue what a bullet tweeter is about? And you actually can acquire decent CD (compression drivers) with decent CD (Constant Directivity) horns for about the same as a pair of ‘decent’ (mid to high range) ordinary dome tweeters. If you only ask, a wealth of suggestions is coming your way. Try it.
Just to be sure, I am not native english, you are referring to waveguides here as something that will increase sensitivity , a typical waveguide with gain capability would be a horn, is that correct understood? ("compression driver /horn in one unit" will mean the same. And yes i would love to use the new midrange B&W 6" with neodym, but its just to pricy yet..) Chose this one because it flushes so nicely, has unlimited spare parts availability (see picture)and plays very well (read load) down to 80 hz in a small ported cabinet 5-6 liter and 85Hz port._-). It play much better now. in its 3 liter sealed box releafed of the 80-250 HZ area,
Yes please , I am asking, I am on thin ice. I have never considered or used a compression driver with any kind of horns in my life. Believe reason to be that it's never the tweeters in car stereo that gives up first, they are in your face, and are super overpowered anyhow, so sensitivity has never been of any focus. (Its way harder to reproduce 80-250 Hz at realistic SPL in the front of a driving car). Same with bullet tweeters, we tested and evaluated them, when I was with Clarion but there was no need for more output in the 2500-12000 range and neodym domes are much easier to place/angle in the car. .
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Sorry forgot to add text, see updated picture, but you are right I miss around 10Db SPL
If you’re short of the means momentarily, have a look at the LaVoce DF10.142LK with FaitalPro STH100 (actually not a CD horn) like Alexander Gresler uses in his “Caveman” speaker. Or use the Eighteensound XT1086 for better constant directivity instead. This way you can get acquainted with the concept, without breaking the bank.
Hello, markbakk , I looked at them, its hard to get a perception of what this is so I choose one of the suppliers (Eighttyeensound) which had products in many of the same ranges as the others to learn, and very resonable price if this is fair/good quality. . If you say XT1086 I only see the horn.. I understand you can buy different drivers fitting the horn, (18 Sound HD1050 50 Watt 8ohm.) Is there a reason you recommend these separa5tre parts or can i buy something like DS18 PRO DKH2 3" Compression Driver w/ Aluminum Horn 8 ohm or the other one attached?
Never seen a tweeter with specs like this, 200 W RMS and 103 db sensitivity, will be the same if I feed my tweeters 1200w approx...
And yes need to test and measure, so will get one first.
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The big advantage of a separate driver and horn is that one can tune things. Look for the directivity pattern. In home applications you would often pick a rather wide angle, like 90 degrees horizontal and 40 to 70 vertical. You also need to consider the low and high cutoff frequencies and in your case I’d pick a range from 1,5kHz upwards.
After that decide on the driver. Another advantage here: you can experiment. Start with proven combo’s or cheap drivers and see if they fit the bill. Almost all compression drivers from serious brands (B&C, BMS, FaitalPro, 18sound, to name a few) are serviceable or are cheap to replace. There is a reason for that of course.
Mounting drivers on horns is the least of your worries (for now). They either screw on or bolt on. With metal horns the driver mostly doesn’t have to be supported, good ABS or other plastic horns likewise.
Bottom line: start with the horn
After that decide on the driver. Another advantage here: you can experiment. Start with proven combo’s or cheap drivers and see if they fit the bill. Almost all compression drivers from serious brands (B&C, BMS, FaitalPro, 18sound, to name a few) are serviceable or are cheap to replace. There is a reason for that of course.
Mounting drivers on horns is the least of your worries (for now). They either screw on or bolt on. With metal horns the driver mostly doesn’t have to be supported, good ABS or other plastic horns likewise.
Bottom line: start with the horn
I am new to this, my first question "online" so to speak. I read the dos and donots (terms and rules), but have probably made mistakes.
What is "car UT videos..."?
What is "car UT videos..."?
What is "car UT videos..."?
I am new to this, my first question "online" so to speak. I read the dos and donots (terms and rules), but have probably made mistakes.
What is "car UT videos..."?