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Old 15th June 2013, 02:39 AM   #181
xrk971 is offline xrk971  United States
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Quote:
Originally Posted by ryani View Post
These sound so much better. Lower extension and has a fuller low-mid.

Can definitely listen without sub help.
I think they don't need a sub because according to the sims, they reach 35 Hz easily.

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Old 15th June 2013, 02:43 AM   #182
ryani is offline ryani  United States
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Thanks for the kind words X. The old man is going to donate his radial arm saw to my arsenal this weekend. So much easier to crosscut with that thing. Now I just need a decent router and I'll be ready to tackle some quality builds by this fall/winter. My mind is racing and the Mrs.' is shuttering.
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Old 15th June 2013, 03:04 AM   #183
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The Mrs is worried about where all the speaker builds will go? You can sell them to friends. I think people will be really amazed at the sound quality of full range drivers. You can't buy this in a store like Best Buy. Do you have a mic and download Holmimpulse. I am curious what the freq resp actually measures out to be.
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Old 24th June 2013, 05:32 PM   #184
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Default The AMLTL method also works for initial sizing of a Met

I needed to optimize the parameters for a Met with a new driver and used this Accidental MLTL technique to come up with the initial size parameters, and it ended up working out almost perfectly after I ran the simulation in AkAbak. Prezden had some Aura NS3-193 high excursion full range drivers that he wanted to use in a bipole Met. I put the T/S params in WinISD and used the default tuning freq but increased the default volume from 14.1 liters to a round 15 liters to get a little more bass extension. Using the formula for calculating the volume of an obelisk (average of top and bottom areas x length) I came up with the upper and lower dimensions after selecting a 40 in length. The vent length in WinISD was 5.35 in and I increased it to a round 5.5 in. I played with the driver location in the sim to reduce the peaks and dips but that was about all the simulation was used for. Had I left it at the default halfway distance for a Met it would have worked pretty well still. Anyhow the results of the sim are in this thread: Help with bipolar Metronome
The NS3-193's can go pretty low for a 3 in driver - about 48 Hz.
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Old 5th July 2013, 11:11 PM   #185
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a couple of questions, if you can help

does an MLTL control the driver cone (at fs) as well as a standard TL or does it behave more like a BR in that way?

And is this a type of MLTL design? About
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Old 5th July 2013, 11:48 PM   #186
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Bill,
Yes, I believe a well designed MLTL controls the cone better than the equivalent BR with same volume and vent dimensions, As far as comparing with a non mass loaded TL, that depends on the design - is it an expanding or contracting TL, and how it is tuned. If you follow the link of the above sim of the Met, you will see the cone excursion plot it levels off flat lower freq - doesn't increase without bound. That helps protect cone from low freq as long as power is not exceeded.

Regarding your question about the Arteluthe speaker, it is some sort of TL, whether or not the term "air cannon" refers to a constriction for mass loading I don't know. For it's size and number of folds, only reaching 40 Hz is not so impressive. Do you really need 700 watts? Compare the measured response to that of my in wall MLTL both reach 40 Hz but I don't have the 6 to 10dB drop from below 100 Hz to 40 Hz. Sounds like it can use some BSC. I can't believe how much they charge for premium speakers - a great reason to DIY.

Last edited by xrk971; 6th July 2013 at 12:08 AM.
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Old 6th July 2013, 10:25 AM   #187
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Quote:
Originally Posted by Bill poster View Post
And is this a type of MLTL design? About
It's the latest version of what Gemme Audio (now that company's defunct) sold a few years back. AFAIK, it's an ML horn, the 'air cannon' appearing to be another way of saying 'duct', 'vent' or similar.


Quote:
For it's size and number of folds, only reaching 40 Hz is not so impressive. Do you really need 700 watts? Compare the measured response to that of my in wall MLTL both reach 40 Hz but I don't have the 6 to 10dB drop from below 100 Hz to 40 Hz. Sounds like it can use some BSC. I can't believe how much they charge for premium speakers - a great reason to DIY.

40Hz is about par for the course.

Re the power, it depends. All other things being equal, the more clean power you have in-hand, the more room you have to manoeuvre. Just as an interesting example, do the maths for the power you would need if you listened to a point-source speaker that is rated at 85dB 1m/w sensitivity from 4m away, at an average of 85dB SPL, but require +20dB dynamic peaks because you like orchestral music (some is actually +30dB, but we won't set our sights quite so high).

In practice, you will almost certainly have a similarly apparently dodgy LF response given that in 99.999% of domestic situations the room dominates < ~300Hz, although the comparison is essentially apples / oranges given the utter dissimilarity of the loading, drive units, design goals and everything else for that matter. I rather doubt it's an issue with baffle-step since it appears to have an F3 of ~100Hz, which would imply a baffle about 45in wide. They state it's a typical in-room plot; the data provided isn't sufficient to make any realistic assessment, so I wouldn't pay it all that much attention.

Last edited by Scottmoose; 6th July 2013 at 10:28 AM.
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Old 6th July 2013, 10:46 AM   #188
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Originally Posted by xrk971 View Post
I can't believe how much they charge for premium speakers - a great reason to DIY.
its funny to recognize v basic drivers in 'high end' audio, albeit good units like Peerless nomex etc
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Old 6th July 2013, 01:10 PM   #189
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+26dB from 85dB requires 2^8.67 or 407 watts. Point well taken - I guess to do classical right you need watts and a driver/speaker combo that can handle it. I have a hard time getting designs that can handle that much power without exceeding xmax. Maybe the Peerless Nomex driver has huge xmax? Although the Karlson is one if the few designs I have seen that really limit xmax for given power applied.

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Old 6th July 2013, 01:31 PM   #190
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And the rest, since the criteria was 4m & SPLs from a point source drop at -6dB for every doubling of distance.

If you want to do large orchestral material at 'realistic' (viz. 'live') SPLs, given that it can hit > 120dB at the listening position on dynamic peaks, then realistically, a system sensitivity of > 100dB is needed. Most people don't have either the money, space or inclination to go that far though (although space isn't necessarily such an issue with a bit of cunning applied for built-in systems).
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