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Old 17th December 2009, 04:15 AM   #1501
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Here's a simulated example - a pro 18" with 9mm xmax and 96 db 1w1m and Exodus Maelstrom 18" with 32mm xmax and 89 db 1w1m.

What does this show? Two very different drivers for two applications. You would never consider them for the same job.

First chart shows 400w input where the pro driver reaches excursion limits (even with a 2nd order highpass that keeps excursion below tuning no greater than above tuning). Where this is enough extension the pro driver seems to have the advantage - more efficiency. We could give it 100w and get the same SPL level. Cone excursion would be less because the vent is helping where the HT sub can't claim that advantage. If the pro driver had sufficient power handling we could extract more output if desired.

Second chart shows the Maelstrom with it's rated thermal limit. It uses most of it's excursion and reaches almost as much SPL as the pro driver but with more than 3x the power - 1.5kw.

All very theoretical so far. If you have a lossy room without room gain and you want to get to 20 Hz or below, then you might start with a monster vented corner sub, and if one driver isn't enough then stack them. Then you might use more efficient subs higher up (the multi sub approach). If you have sufficient room gain and/or don't want to get down so low then I'd say efficiency makes more sense.

Sorry Earl, I should resist the temptation to get off topic on your thread.
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File Type: gif pro-vs-ht-sub_1.gif (25.0 KB, 262 views)
File Type: gif pro-vs-ht-sub_2.gif (25.1 KB, 252 views)
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Old 17th December 2009, 04:48 AM   #1502
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It's very curious that people are disputing basics when I haven't said anything inconsistent with what everyone was agreeing about earlier today.

Earl, doesn't what you're saying apply to any driver?

Quote:
Originally Posted by gedlee View Post
Depending on what you meant that might still be wrong. Its 6 dB more input power for 3 dB more acoustic power, 6 dB more SPL. Thats exactly my point. As you try and go lower and lower in frequency the growth of required input power goes up faster than the acoustical output power resulting in a run away situation that Matt is quite correct in pointing out. The only way to get 3 dB more acoustical power with 3 dB more electrical power is to use two sources - hence back to why I use multiple subs and not one mega sub.
Paul, is your comparison using the same box size and Fb?

Here is a simulation showing a Mael 18, and a single and pairs of B&C 15TBX100, all in closed 8 cf boxes and 1000 W input.

Shrinking the box to 3 cf compresses the differences to a range of 3 dB.
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File Type: jpg spkrs.jpg (165.9 KB, 251 views)
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Last edited by noah katz; 17th December 2009 at 05:02 AM.
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Old 17th December 2009, 05:39 AM   #1503
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Noah - no. The Maelstrom has a bigger box, but both are huge. They aren't suited for the same tuning.
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Old 17th December 2009, 06:56 AM   #1504
gedlee is offline gedlee  United States
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Hi Paul, Noah

Noah - yes what I am saying applies to any driver when you try and extend its capability lower in frequency, but the limitations of most drivers differ for LFs and HFs. LF drivers tend to be excursion limited while HF drivers have thermal problems. So they don't act quit the same

I'm not going to be able to enter into this discussion any deeper, because 1) its about something at an extreme that I don't deal with very much, and 2) using free field simulations is just not useful for the real response of a system in a small room. I'm sure that Paul has a point, but it seems very specific to a particular set of drivers and not a general principle. As a general principle I don't believe in single subs and I don't try and go as low as is being shown. In the multiple sub situation in a real room where one is using EQ, a completely different set of criteria if required.
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Old 21st December 2009, 05:35 PM   #1505
gfiandy is offline gfiandy  United Kingdom
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Hi, I have just been looking at your speaker designs. If they sound as good as people say (and I have no reason to doubt it). I think you are doing yourself a disservice by not improving the appearance.

Only HiFi nuts actually like to look at drive units, would it affect the response if you had a foam grill over the whole of the front? I belive this would broaden the appeal.

I realise this is probably not possible at the moment but I would also work towards real wood vinear on as much of the cabinet as possible. Wood finishes intergrate into most homes much better than black.

I would really like to see you succeed with this as I had to get out of audio due to the recession. I admire your dedication to producing something that has real design integrity rather than just marketing. However marketing is important as well and most people buy things with their eyes, however much they think they don't.

Best of luck. Andy.
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Old 21st December 2009, 06:05 PM   #1506
gedlee is offline gedlee  United States
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Quote:
Originally Posted by gfiandy View Post
Hi, I have just been looking at your speaker designs. If they sound as good as people say (and I have no reason to doubt it). I think you are doing yourself a disservice by not improving the appearance.

Only HiFi nuts actually like to look at drive units, would it affect the response if you had a foam grill over the whole of the front? I belive this would broaden the appeal.

I realise this is probably not possible at the moment but I would also work towards real wood vinear on as much of the cabinet as possible. Wood finishes intergrate into most homes much better than black.

I would really like to see you succeed with this as I had to get out of audio due to the recession. I admire your dedication to producing something that has real design integrity rather than just marketing. However marketing is important as well and most people buy things with their eyes, however much they think they don't.

Best of luck. Andy.
Thanks Andy a very typical comment.

How much do you think people would be willing to pay for all these upgrades? Thats really the question isn't it. I CAN do all of that stuff, but at a price. Of course some people want the "appearance extras", but they don't want to pay for them. I find, in general, that if appearance is important enough for them to comment, then they aren't really all that interested in the sound quality and they go elsewhere anyways.

All that I can compete in is "sound quality". That's what I offer and that's what I deliver - the "brand promise" if you will. Others claim "sound quality" but all they really deliver on is appearance. If that's enough for the customer then they are happy, but if they are expecting sound quality then they will be disappointed. Not so my customers.

The next generation of cabinets will allow for grills and have the screws hidden. Thats easy, cost effective and does not have seveer performance implications. Almost anything else does.

Last edited by gedlee; 21st December 2009 at 06:09 PM.
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Old 21st December 2009, 06:12 PM   #1507
pjpoes is offline pjpoes  United States
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And might I add that simple grills can be fashioned in a way that doesn't compromise sound with the current setup. As mentioned in other threads, a fabric grill could be created to fit over the woofer. A metal grill could be fashioned as well in the same way, but would require forming into shape. I've also thought that a fabric "sock" grill would work fine too. Might not look as good, but is probably an easy way to cover the drivers completely and keep prying fingers out.
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Old 21st December 2009, 06:16 PM   #1508
gedlee is offline gedlee  United States
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Quote:
Originally Posted by pjpoes View Post
And might I add that simple grills can be fashioned in a way that doesn't compromise sound with the current setup. As mentioned in other threads, a fabric grill could be created to fit over the woofer. A metal grill could be fashioned as well in the same way, but would require forming into shape. I've also thought that a fabric "sock" grill would work fine too. Might not look as good, but is probably an easy way to cover the drivers completely and keep prying fingers out.
Yes, I have fited grills simply but tertching fabric over the woofer and press fitting it all the way around. Woks fine, I just don't like the look. I don't like see the screws, but I don't like the look of the grill cloth either.

Download the jpg from my site and use photoshop to blank out the woofer. You will see that it looks kind of cheap - like your trying to hide something.
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Old 21st December 2009, 07:11 PM   #1509
gfiandy is offline gfiandy  United Kingdom
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Well none of your speakers come in at under $1000 US and I would think you could add the grills for about $50 max if they were foam held on with velcro.

I think it would increase sales to the bigger market of people who are interested in both a nice looking speaker as well as a good sounding one but if that is not your experience, I can't really argue. Perhaps the design is just a bit to esoteric to break into the main stream, it didn't seem that way to me.

Either way best of luck with it.

One other thing I thought of; however I have not looked carefully at the requiremnts for your horn. Could you vacuume form it from plastic then damp this, as this is a quite cheap way to make things with a simple wooden former.

Regards,
Andy
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Old 21st December 2009, 07:54 PM   #1510
sts9fan is offline sts9fan  United States
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Earl's cast waveguides are awsome. It would be a bummer if he made them cheaper.
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