Diameter VS high excursion - AVS Forum
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Old 06-13-2013, 02:29 PM - Thread Starter
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Hello,

Do you think it's better a big sub with low excurtion, or a smaller one, but with high excursion?

For example, do you prefer a 15" with xmax of 5 mm or a 8" with 50 mm xmax?
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Old 06-13-2013, 02:40 PM
 
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I want more excursion. A 15" driver with a 25mm excursion will catch my attention every day. Personally, I don't think a 15" driver with a 5mm excursion is noteworthy. Is this a driver you're looking to purchase?

As an example, here's a 4 Ohm, 15" driver with a 14mm excursion one can purchase from Parts-Express.

Dayton Audio RSS390HF-4 15"

The least expensive driver has an Xmax of 8.4mm.
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Old 06-13-2013, 03:43 PM
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ideally there is a balance. For example at some point usually around 30mm Xmax one way you start running out of benefit for a reasonable cost by trying trying to increase xmax anymore. Also you need to consider that at certain point xmax doesn't matter sense higher frequencies upper bass for example is about surface area of a driver ,number of drivers, power handling ,and power the amplifier can deliver.

Your given example doesn't make sense getting a driver to 50mm xmax one way is waste of time. It can be done but it will very expensive and you might consider more drivers or a big driver.

In general driver size isn't a choice. Driver size is usually dictated by box size, power available, budget and generally the type of subwoofer you want to make (sealed , ported ,horn, ecte) and again size.

For example generally the biggest quality driver makes sense. But for example many don't use 18's because their really big and require a lot of box size. So for example people might use two 15 inch drivers to get in the same ballpark of surface area.

ShaunH
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Old 06-13-2013, 04:02 PM
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It also seems like it is easier to make a larger driver with good excursion than a small driver with good excursion. Usually larger drivers from the same product line will have more excursion, i'm not sure if that is just a result of larger parts in general?

And while we're on the topic has anyone tracked down some info on the balance between excursion and surface area?

For example if driver a) is twice the size of driver b) but driver b) has twice the excursion of driver a) will they both be capable of the same spl, all things being equal, or does it scale differently?
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Old 06-13-2013, 04:30 PM
 
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Quote:
Originally Posted by Mik James View Post

And while we're on the topic has anyone tracked down some info on the balance between excursion and surface area?

For example if driver a) is twice the size of driver b) but driver b) has twice the excursion of driver a) will they both be capable of the same spl, all things being equal, or does it scale differently?

This calculator is for a sealed box but, regarding an answer for what you're asking about in your above, it might give you ideas.
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Old 06-13-2013, 04:47 PM
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Originally Posted by SystemHDS View Post

Hello,

Do you think it's better a big sub with low excurtion, or a smaller one, but with high excursion?
Distortion is proportional to excursion, and larger cones more efficiently couple with the very low impedance load of air, so larger cones are better. Technically speaking the main reason to go to a smaller cone is when the angle of dispersion dictates it. That's why tweeters are smaller than mids, mids smaller than woofers, woofers smaller than subs.
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Old 06-13-2013, 05:51 PM
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Quote:
This calculator is for a sealed box but, regarding an answer for what you're asking about in your above, it might give you ideas.

Answered both the question I asked and another regarding frequency and excursion. Thanks smile.gif
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Old 06-13-2013, 07:24 PM
 
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Originally Posted by Mik James View Post

Answered both the question I asked and another regarding frequency and excursion. Thanks smile.gif

...biggrin.gif
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Old 06-14-2013, 04:39 AM - Thread Starter
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If i want to have a lot of punch between 50-80 Hz, what type of subwoofer are suitable?

A 10" driver can have the same energy at punch frequencies as a 15" or 18"?
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Originally Posted by SystemHDS View Post

A 10" driver can have the same energy at punch frequencies as a 15" or 18"?

Your above reads as if you want a 10" subwoofer.

The larger subwoofer drivers output more energy into a room and have deeper extension with the ideal being a subwoofer system capable of high quality, low distortion output: <10% THD, <20Hz at >115dB.
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Old 06-14-2013, 06:11 AM
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Originally Posted by SystemHDS View Post

If i want to have a lot of punch between 50-80 Hz, what type of subwoofer are suitable? A 10" driver can have the same energy at punch frequencies as a 15" or 18"?
The size of the driver has little to do with the frequency response. If you want to know how a particular driver and enclosure will work use speaker modeling software, like WinISD Alpha pro.

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Old 06-14-2013, 08:37 AM - Thread Starter
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i'd like to know what type of subwoofers have a lot of punch, and what parameters are needed to get it.

For example, if the amplifier must have a good damping factor, or slew rate, ecc..
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Old 06-14-2013, 09:07 AM
 
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Originally Posted by SystemHDS View Post

For example, if the amplifier must have a good damping factor, or slew rate, ecc..

Just saying, it reads like you're getting deep in the weeds and fell into a rabbit hole if wanting to know about damping factor or slew rate while wanting to know the difference between 10" drivers vs 15" and 18" drivers.

In real terms, based on your first and second post, maybe you can say what the size of your room is and what type of budget you're working with as any of the internet direct manufactures will have plenty of punch.
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Old 06-14-2013, 09:50 AM
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Originally Posted by SystemHDS View Post

Hello,

Do you think it's better a big sub with low excurtion, or a smaller one, but with high excursion?

Set your SPL and frequency range goals and whatever gets you there with the least amount of excursion is best, all else being equal.

This doesn't have to be about the actual driver itself, lowering of excursion can be had with using multiple smaller driver units.

So assuming your hypothetical big and small subs have identical max spl and frequency range, the bigger one should have less distortion, self noise, need less amp, but its bigger. It all depends on what suits you and your situation. Pick the right tool for the job.
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Old 06-15-2013, 10:48 AM
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I have 2 mid-priced Velodyne 10" DSP ported subs in my medium size HT room. The EQ-Max 10 would be the equivalent now I guess. They provide me with perfectly fine LFE with lots of impact that gives me a great HT experience. In fact, unlike many here & perhaps because I'm now an old phart, I wouldn't want anymore performance because I find that often soundtracks are way over done and really don't correlate to what I see on my 55" screen.

When I first ran Audyssey, I had set the subs' volumes at 4 of 10. That proved to be way too high and eventually after some tweaking, they are now set at 2 of 10 that brings them nicely into the middle of Audyssey's correction range. They produce sound down to 23 Hz and still create room effects - buzzing & rattling - in my room down to 20 Hz, although nothing is audible. I find that the vibrations and noises produced by my metal gas fireplace and furnace ducting in the walls & ceilings are quite annoying - like a rattle or squeak in my car.

In my audio-only tube amp sats/subs system, I have 2 EP400 8" sealed DSP 500W/CH subs that are wonderfully articulate and are absolutely stunning for music. No towers that I auditioned within a reasonable price range equaled the performance of this smallish setup.

For me, smaller is better...

TAM
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Old 06-15-2013, 11:26 AM
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Quote:
Originally Posted by SystemHDS View Post

Hello,

Do you think it's better a big sub with low excurtion, or a smaller one, but with high excursion?

For example, do you prefer a 15" with xmax of 5 mm or a 8" with 50 mm xmax?

First and foremost, I would prefer a 15" with 30 mm excursion, especially in pairs.

I have problems thinking of anything under 12" to be a subwoofer.

What was the question again? ;-)
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Old 06-15-2013, 11:38 AM
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I'd like to know where the op found these 8" woofers that we're clearly handcrafted by the gods biggrin.gif
50 mm of excursion in a compact 8" for the price of a 15" with 5mm would be a quick sell to me, if it was any good.
The value is in the larger woofers with half decent excursion, a Tc sounds epic 12" for example is only 30$ more expensive than a tc sounds epic 8"
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Old 06-15-2013, 02:06 PM
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Quote:
Originally Posted by SystemHDS View Post

i'd like to know what type of subwoofers have a lot of punch, and what parameters are needed to get it.
Punch isn't a term that has any technical definition, so one can't say what will provide it.

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