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#1 |
diyAudio Member
Join Date: May 2020
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Hi, I am currently designing a speaker for my bedroom. I have read many post regarding to speaker compatibility in sealed or closed encosure and saw two different method for calculating it. Some say QTS >0.5 is better for sealed and some say EBP <100 is better for sealed.
My problem lies in the current driver that i own where the QTS is 0.641 but the EBP is 130-ish. My question is, better sealed or ported for my driver in small listening room (bedroom TV)? Keep in mind that the speaker will almost have no gap to the walls (approx. 1-2cm). I have modeled it on WinIsd, and on the ported enclosure the cone excursion is more than 10mm below tuning frequency (20W Input). Is the WinIsd cone excursion simulator accurate? As i am afraid to damage my drivers via over excursion since i don't know what the Xmax rating of my drivers are. Help is appreciated, many thanks! P.S. I attached the driver files obtained via TangBand |
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#2 |
diyAudio Member
Join Date: Apr 2014
Location: Wodecq, Belgium
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EPB is the most important one for this, and with an EPB of 130 i would use ported, but more likely a TL with that high QTS.
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#3 |
diyAudio Member
Join Date: May 2020
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I currently have no resource to build a TL. If i placed the speakers right up against the wall, will it be worth the trouble designing it as a rear ported speaker (Can't make it a front ported because of size constraint)?
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#4 |
diyAudio Member
Join Date: Mar 2005
Location: UK
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EBP is a 1st order approximate guideline which attempts to provide a rapid indication what types of load a drive unit is suited to. Personally I regard it as bordering on worthless, since it can lead people right up the garden path, assuming that a driver 'can't' be used in xyz when that is not necessarily the case in practice.
Short version: it doesn't matter what the EBP derivation is if the alignment suits your requirements. The latter is what counts, so if you can hit your desired alignment, job done. Driver excursion is a completely different matter. A vented box ultimately unloads 4th order (24dB/octave) at some point below tuning, exactly where & how depending on the specific implementation. So if you feed it with material that has a lot of output significantly below Fb, the driver will unload & flap about as though it's in free air (because in essence, it is at those frequencies where it no longer has any air-load from the enclosure). A sealed box is always safer in that sense. You might want to look at a folded TABAQ, it was designed for the TB units, so this one may suit (I haven't time to check right now, but it looks in roughly the ballpark from memory) and should get to to 50Hz. These are all small drivers though, so ultimately a little mechanical sympathy / expectation management (aka common sense) is required: there is only so much air you can shift with a 3in cone, so if you see it moving a large amount, turn the volume down. ![]()
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www.wodendesign.com (commercial site) www.frugal-horn.com www.frugal-phile.com (community sites) Last edited by Scottmoose; 19th January 2021 at 06:41 PM. |
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#5 | |
diyAudio Member
Join Date: Apr 2014
Location: Wodecq, Belgium
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Quote:
And about the bass quality of a 3", it's true that it won't give much bass, for that you need a bigger driver. A 5 or 6" can do a lot more than any 3" on that. I would pair it with a woofer if you want to use this driver and have bass. And the winisd is accurate on xmax and how much bass you get from your driver. |
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#6 | |
frugal-phile(tm)
diyAudio Moderator
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Quote:
EBP is something i pay zero attention to. dave
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Stay safe. Stay home. Respect the 2m bubble. |
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#7 | |
frugal-phile(tm)
diyAudio Moderator
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Quote:
dave
__________________
Stay safe. Stay home. Respect the 2m bubble. |
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#8 |
diyAudio Member
Join Date: Jun 2003
Location: Chamblee, Ga.
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FWIW: Enclosure Dilemma
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents. |
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#9 |
diyAudio Member
Join Date: May 2020
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So, I sim some more on WinIsd and come up with an enclosure size of 8.1L which give me a QTC of 0.717 in a sealed box. I attached some files of my sim and wanted to ask if the ported is a better way to go or just build a sealed box and just add a sub since it will be easier to implement (12db roll off). Thanks!
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#10 | |
diyAudio Member
Join Date: Aug 2008
Location: Dolceacqua
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Quote:
The program is right and yes you can damage the drivers with low frequencies content. I guess your driver can only swing +/-1 or 2 mm, because of the relativly high efficiency. Similar TB 3" indicate this. Also the enclosure will be quite large for a reflex, better and cleaner bass with a TL, a target of 100Hz would require a short 75cm line. Only a closed box wouldn't need a high-pass filter could be small, but has high f3. If you mount the chassis diagonal in the corner, there would not be any baffle step but even an increase in bass energy(+3dB), maybe your program can simulate this too. |
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Thread | Thread Starter | Forum | Replies | Last Post |
Would it be okay to mix Low qts and high qts of the same sub? | icecreamxd | Subwoofers | 7 | 4th December 2013 09:00 PM |
what sounds best . . . Low Qts in small cab or higher Qts in bigger cab | mikelm | Subwoofers | 18 | 15th July 2009 11:46 AM |
EBP and QTS | horus | Multi-Way | 27 | 2nd January 2007 01:29 AM |
What if instead of a speaker with a Qts=1 I use a different Qts?? | Tuliman | Multi-Way | 2 | 14th December 2004 12:54 PM |
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