Does Port Length Really Matter?

I am designing a box for 2 JL 10" subs and have a question. Does port lenght really matter? I ask this since all the things I read say that you should use the calculators or the manufactures suggested lenghts but here is the problem.

Bose wave radios work on a design which is one huge port. I have one and it's amazing. The bass that I get from these 2.5" speakers are amazing. But the port lenght is just as long as what is suggested for my 10" sub. So what gives? Does a longer port take away from the bass or enhance it? Bose gives the analogy of a whisper in a flute can fill up a concert hall with sound. Small movment but a long focusing chamber or port. What are some peoples ideas about this?

Thanks for the input!

Don't believe what BOSE says. It's all marketing hype.

Don't believe me?? Check this out.

BOSE Acoustimas Review

Or this.

https://www.audioholics.com/forums/showthread.php?t=3266

Paul

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The problem is that Mr. Bose doesn't have an engineering degree.  He has a marketing degree.  They make the cheapest possible stuff and market it to make people think they are getting something incredible for their huge sums of money.  And they are hugely successful at it.  I could let you listen to our cheap $150 kits and you would be blown away by how much better it sounds than the wave radio, or anything Bose makes for that matter.

Steven Kephart

Adire Audio

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they say it's not really the size that matters, it how you use it. Sorry, I had to say that.

Port length is a critical part of what determines the tuning frequency for the enclosure.  Yes, port length matters.

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Support the12volt.com

Also, the Acoustimass system is NOT a ported system. It is a quasi-transmission line. Look it up, I don't want to get into it right now - too early. (Also, it's a HUGE chunk of ****, and Dr. (yes, he's got a label) Bose saw you and a million other "audiophiles" coming - sorry, man) Seriously, though, if you like it, keep it. It's just that I disagree with the company, and they would never get a dime of my money, and their systems sound awful to me.

Bose uses over 80% of their annual revenue for MARKETING. It is the only company on the face of the planet to do so, and because it is a small company (employee-wise) they can still afford to do this.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

haemphyst wrote:

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and Dr. (yes, he's got a label) Bose saw you and a million other "audiophiles" coming - sorry, man)

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That's right, it was Doctor.  I think it was our Doctor that told me that it was in marketing, not engineering.

But anyway as they said, if you like it then ignore what we say about the company.  You have a product you enjoy, and that's all that matters. 

Steven Kephart

Adire Audio

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Amen to the Crap, err.. Bose opinions.  But back to port length as DYohn said, port length is critical to tuning the frequency of your enclosure.  Ported boxes can sound amazing if they are properly contructed and tuned.  The only problem is that it only takes a little miscalculation to screw up a days work, so build it carefully.

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If it don't fit, Force it.
If it breaks, You needed a new one anyway!

yes port length matters alot. length and width and port displacement (air volume inside the port) in calculated ratio to the volume of air and the theile small parameters of your speakers determins the tuning frequency.... with the BOSE system you are talking about they are trying to mimic a "transmision-line" box... thats a whole nother storry, if you dont know about tuning frequencies dont bother trying to understand what a trans-line box is

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Aaron

Ahh... BOSE. "Better Sound Through Propaganda" However, there are a lot of interesting physics going on in behind the advertising. Their home audio kinda sucks... but, head over to the commercial side of things. Hook up a Panarray system, feed it with 2.5K RMS of good clean power, and listen to it hammer. As a live audio tech, I have used a lot of their commercial stuff, and, when properly deployed, it works exactly as it says it does. Good dispersion, good pattern control, decent fidelity. Not saying it's the best stuff out there, but it isn't the worst either.

Gus


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Wherever I go, that is where I end up......

Thanks so much for all of the info. For the first time, I don't think that Bose is that great anymore. Looks like I'm going to think different.

I have one more question. Does a bend in the port matter? Say if my calculated lenght is longer than the depth of my box, can it have a bend in it? I've seen a recommended design for a different JL sub box that has a bend in the design. Does the bend affect the frequency at all?

The bend in the port will not make the system sound any different, as long as the bend is calculated in the equation when you are designing the port

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer