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Old 17th February 2006, 10:21 AM   #1
Hayden is offline Hayden  Australia
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Default Long excursion vs short

Which will have better bass?

Long = more throw but less cone area
Short = less throw more cone area
The long probably handles more power.

Your thoughts


You can work it out by the technical data but it would take me awhile I havenít done this kind of thing before.
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Old 18th February 2006, 01:47 PM   #2
bigwill is offline bigwill  United Kingdom
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Short throw big cone area, less distortion
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Old 20th February 2006, 10:22 AM   #3
Hayden is offline Hayden  Australia
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I originally though that long excursion subs where better for spl but I was wrong seeing a lot of world record spl vehicles using short throw subs, is that true? or do they have more money than sense
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Old 20th February 2006, 11:00 AM   #4
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For sheer output, what counts more than anything is sensitivity. Large excursion drivers tend to be significantly less sensitive due to the limitations of the structure of the motor assembly.
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Old 20th February 2006, 12:55 PM   #5
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They're the same, what matters for output is displacement, which is equal to cone area * excursion. Sensitivity only comes into play when you're talking about how much power is required to reach a certain level of displacement.

The reason several "short throw" speakers are winning spl competitions is because you're only looking at Xmax, which is the linear excursion. Most spl subs have an extremely peaky BL which gives them a small Xmag and therefore a small Xmax, but their Xmech is very, very large. That means that while they can't move too far linearly, they can move very far physically, and since spl competitors don't care about distortion that's fine.
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Old 21st February 2006, 10:35 AM   #6
Hayden is offline Hayden  Australia
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Sorry but Iím new still learning (hence why Iím here) sr20dem0n can you explain it a bit more? I know about displacement being important (Xmax, Xmech) confuses me.
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Old 21st February 2006, 02:45 PM   #7
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Xmag = linear excursion of the motor
This corresponds to the point where the BL (the "strength" of the motor) has fallen to 70% of its rest value. What this means is that when it's near 0mm excursion, the cone is moving as if it's going to reproduce the input wave in its entirety. However, as the cone moves farther and farther from rest, the motor loses strength and the peak of the wave gets rounded off. This introduces harmonics and intermodulation distortion into the signal, which isn't good for sound quality obviously.

Xsus = linear excursion of the suspension
This corresponds to the point where the suspension's compliance has dropped to...25%? <unsure> of its rest value. Basically the same thing happens to the sound as at Xmag.

Xmax = linear excursion of the driver
This is the lesser of Xmag and Xsus, it is simply the point at which a noticeable amount of distortion is starting to entire the sound either because of the BL dropping or the suspension losing compliance.

Xmech = the maximum excursion of the driver
Linearity has no weight here, this is the point at which things start to get damaged. This could be when the spider or surround pulls taught and is about to rip, it could be when the former crashes into the top plate, etc. This is what matters in spl competition, and it's almost completely unrelated to Xmax (it will be greater than Xmax, naturally, but it could be 5% greater or 200% greater, there's no telling)




When you're looking at these "short excursion" drivers that are winning these spl competitions, take a peak at their mechanical excursion instead of their linear excursion and you may start to see why. Take the DD subs for example, they hold several records for spl but they only have a ~12mm Xmax. Now there are plenty of drivers with an Xmax of 30mm but they aren't as loud...why? Because the DD subs have a very peaky BL (DD 9515 vs JL 10w7), their motor moves out of linearity very quickly, which gives them a small Xmag and therefore a small Xmax, but the 95xx series DD subs can move almost 40mm one-way before hitting their mechanical limits (Xmech). So at first glance it appears to be a short excursion driver, and when you're talking about linear excursion it is, but when you push it into the non-linear range, as they do in spl competition, it's actually a very very long excursion sub.
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Old 22nd February 2006, 06:40 PM   #8
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Quote:
Which will have better bass?

There is a difference from better and MORE. Do you want quality bass (SQ or SQL) or just want to be loud and don't care what it sounds like (SPL) ? Polo..
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Old 23rd February 2006, 09:00 AM   #9
Hayden is offline Hayden  Australia
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thanks sr20dem0n that helps alot

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just bass not that audible, lower frequencies for vibration, I like knocking over objects with my subs
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Old 25th February 2006, 08:43 AM   #10
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Better bass in relation to what?

Realistic bass has very little to do with large or small cones or the excursion.

A woofer is one part of a system and for me to say better bass, you need to mention the enclosures construction, the amplifier and when you say better bass, do you mean accurate to the recording or just impressive sounding?

It sounds like you want low rider bass and for that the larger the excursion and the larger the cone area and a correctly specified enclosure will give you what you want, thats not better bass, thats just really deep high output bass.

You can not have better bass than what has been recorded on the disc, so i need to know what you want to answer your question, hope this helps.
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