Absolutely right, too.
I wish all these unfounded "myths" just died once and for all...
Have you ever been in a small multi-sub studio?
I found the subs aren't even used most of the times.
Car audio...
Aston Martin DB9 & Vantage, BMW 7-series, Bentley Continental, Mercedes S-Class, Volvo S90, Audi A8, Porsche Cayenne and 911s, Lexus LS....you name it.
A car interior is about the worst space for sound.
Subs in cars: if you want the girls or kids in the back to feel sick, those are perfect instruments.
It's not about reproduction per se, it's more about reproduction relative to the environment.
Just my 2c.
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Simple, the horn or waveguide expands the sound in a controlled fashion in a more coherent way. Once the waves reach a certain distance into the room then all this organization is fully expanded to optimal, then the farther you move it becomes disorganized by the room again.
If you move too close to the waveguide, the sound in low frequency is not fully expanded and can have peaks in the mid-range, prefer to listen at the XO optimal crossing distance which is in the 500s down 8 or 12 db octave which requires at least 1.5 to 2.5 meters.
If you have a conventional speaker without horn/waveguide, you can adjust the XO for close range listening easily.
There's some merit in your argument, but it largely depends on:
- the (type) of horn/waveguide
- the size of the horn(s) and the rest of the (loudspeaker)system
- the space, again.
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'Once more into the breach!' As presented, not this particular 'story': http://stereointegrity.com/wp-content/uploads/WooferSpeed.pdf
GM
Thanks gm. Notice that I didn't mention what does impact subjective "speed", just that using impulse response and inductance as a guide tells us nothing the way I see it because a low passed signal sent to a woofer MUST have a slower impulse by definition of being low passed. I don't know what it is that determines subjective woofer acceleration, and I don't want to derail this thread, but the article cited makes assumptions that impulse response tells the story while I don't believe that's the case. Now if one were using the driver high enough that the inductance became relevant, then sure. In a low passed situation however, it's the mid or tweeter that is sharpening up the impulse response. Perhaps it's the derivative of acceleration "jerk", its ability to change acceleration that might reveal something. To my knowledge, that wouldn't be revealed in measurements?
Excuse me but... could you say why there is no extremely large OB coaxials, they are able to expand the direct field to the listener position.
A medium sized tractrix horn with a 2" compresssion driver unit into a fostex FW800 could do the job without the need of a large Xmax.
I can think of many reasons, but I am not an OB proponent, because of the basic concept (back wave vs room).
That's not to dismiss OBs entirely. I just don't like the limitations, of which low efficiency is just one.
You'll have to solve quite a few conflicts, in order to get a coax (woofer + comp.) to work nicely in an OB.
Doesn't mean it can't be done, but I don't see the merits.
With regards to vintage cinema: In the US, during the 1940s OBs were replaced by front loaded woofers (often in combination with reflex ports).
That's not to dismiss OBs entirely. I just don't like the limitations, of which low efficiency is just one.
You'll have to solve quite a few conflicts, in order to get a coax (woofer + comp.) to work nicely in an OB.
Doesn't mean it can't be done, but I don't see the merits.
With regards to vintage cinema: In the US, during the 1940s OBs were replaced by front loaded woofers (often in combination with reflex ports).
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For a subwoofer you would want a decent inductance which means there is a nice voice coil ready to transfer electrons to powerful bass.
The added 'impulse delay' of the inductor is compensated with higher power and you don't want high frequency, I don't see any problems, mass is the big problems: reduces efficiency, makes VC heat, create THD, create phase delay at higher frequency as shown in the Adire audio document.
The added 'impulse delay' of the inductor is compensated with higher power and you don't want high frequency, I don't see any problems, mass is the big problems: reduces efficiency, makes VC heat, create THD, create phase delay at higher frequency as shown in the Adire audio document.
for room size a dose oIdeal Room Size Dimensions and Ratios for Audiophile Listening - Audiophile Reviewf reality:
Why use an ob if you could have this?:
For sure. High quality high volume playback in one box.
Still, the JBL M2 really checks the OP’s boxes no matter that he dismisses them as just another flat two way box. The M2 leaves the old 4430’s so far in the dust in every respect save appearance, it’s amazing
Barry.
o. another thing for bass addicts, the harder the walls and the floors the worst the bass...
Basements are about the worse places to have a sub-woofers and home theater. Bass bounces like crazy on the concrete floors under the carpet and corks and whatever you place there...
Hardwoods floors too is bad if supported by thick plywood sheets.
The best bass rooms are high ceilings, very deep, with cheap rotten floors with carpets, I speak from experience.
Give me the choice between a 12x18x8 room in concrete with 15 x dual subs or, a 22x45x10 room with a bouncy floor and a 2 way with 8 inch.
I will choose the second and laugh at your boom box with poor bass and earache, my room will have palatable deep bass that shakes everything and pressurize your hears while clear.
Basements are about the worse places to have a sub-woofers and home theater. Bass bounces like crazy on the concrete floors under the carpet and corks and whatever you place there...
Hardwoods floors too is bad if supported by thick plywood sheets.
The best bass rooms are high ceilings, very deep, with cheap rotten floors with carpets, I speak from experience.
Give me the choice between a 12x18x8 room in concrete with 15 x dual subs or, a 22x45x10 room with a bouncy floor and a 2 way with 8 inch.
I will choose the second and laugh at your boom box with poor bass and earache, my room will have palatable deep bass that shakes everything and pressurize your hears while clear.
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Totally agree Barry! A few members have reached out to me to share their JBL M2 measurements using Audiolense digital XO and eq. The M2 is the only two way I have seen in-room measurements for that legitimately make it from 20 Hz to 20 kHz, with high output and low distortion.
My JBL 4722's 2-ways make it from 40 Hz to 19 kHz with the large format 4" Ti aquaplas CD. I ended up adding dual subs to the setup...
Project M2 DIY Thread on Lansing Heritage site
Kind regards,
Mitch
Yeeeeaaa another person with Aquaplas titanium! What is your experience? Only thing better is Beryllium from what I can tell. If noticed with my xover points, 130hz between the 15h and 15m....thats pretty much all sub territory, though 80hz and below is closer to technical sub territory, the low pass on most subs tops at 130hz....I think GM suggested 60hz as a Xover point even. Once I have the system built I can experiment. From experience I can say that serious excursion begins at about 200hz-130hz and below.
ON the M2, I don't feel like I am downplaying the sophistication of the M2, rather, I am not intimidated. Theres nothing about the M2 that isn't repeatable, is my point. Even if its just simply buying the same drivers and putting them in a box. the crossover point is 800hz? So theoretically I could buy the same drivers and horn, put them in a box, and have a DIY M2. The active crossovers aren't magic and the drivers are purchasable to the masses. Enclosure is at the mercy of ones skills. Are you telling me that there is no other 2 way design that even compares to the M2? If thats so, the drivers are still the mainstay of the M2's allure. has anyone even tried to replicate the M2 results using the AE drivers? Sounds like the the Jbl M2 driver is the best of the AE 15m and 15H combined. Lets not leave out that the M2 compression driver isn't exactly the end all driver, there are people with better ears and experience than I who have made it clear that the 4" Diaphragms have something that the M2 compression driver is lacking....."Authority" being one the words I see repeated. As well, the M2 Cd isn't that great below 900hz from what I've gathered in my studies. The lower the crossover the better I say, and 800hz on a 15" isn't exactly choice from my calculations of Ka. I still believe in the M2 and that it is what I want in a two way, its just that I attempted to reach for those type of specs in a DIY and ended up with a 3 way.....lol...I haven't purchased woofers YET, don't think I won't buy the 2216ND lol!!
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