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Multi-Way Conventional loudspeakers with crossovers

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Old 17th June 2018, 06:44 PM   #61
Best Hi End is offline Best Hi End
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Thanks Scott,I understand that I should select 18' Pro driver rather on dual 12' drivers to go flat 20Hz -if so,would you be kind enough to recommend me,in your opinion, the best possible 18' driver to go down to 20Hz up to 300-500Hz without choking or distortion with excellent Fs and Xmas with relatively "smallish" sealed enclosure ?
Your set seems amazing-is it an infinite baffle on the upper left side,what drivers&horns do you use ?
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Old 17th June 2018, 07:01 PM   #62
KaffiMann is offline KaffiMann  Norway
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Location: Grua, ten minute walk from 60.258792, 10.664731
Where in the world are you located?
There can be quite large variations in price on various brands pending on your geographic location. If you want some suggestions on 18" pro drivers, give a mention of which site, store or country you would like to order from.
There are many suitable 18" available, no need to pay extra for the same performance.
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Old 17th June 2018, 09:14 PM   #63
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I'm from Israel,but I can order worldwide .
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Old 21st June 2018, 08:59 PM   #64
DougL is offline DougL  United States
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FYI
Here is a site that deals in the basics of horn design.
For a 20 Hz horn, you need an 8 Meter length and a mouth diameter of 8.5 meters per this site.
Folded horn speaker design - explanation and calculator

I have heard of people using a shipping container as a basis for a 20 Hz horn.

Good luck with your project.
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Old 21st June 2018, 10:30 PM   #65
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Thanks for the info. and advice.I'll forgo sub horn and settle for ordinary subwoofer and use horns for the rest.I tend to select Mach 5 -it seems one of the best 18' or even 21' drivers that can go down to 20Hz with great Fs and Xmax-are you aware of any better 18' or 21' drivers with better data and sound performance ?!
My only problem is that I don't know what is the minimum size of sealed enclosure I should build for it ?
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Old 21st June 2018, 10:51 PM   #66
LineSource is offline LineSource  United States
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Quote:
Originally Posted by kazap View Post
Can I ask about the issue of being able to locate a subwoofer or IB located away from the main stereo speakers? What crossover frequencies allow subs to disappear.
Have you researched maintaining stereo woofers in your room, like a front/back quartal configuration, versus summed mono woofers?

1) Stereo bass down to 20Hz has been produced in low distortion, high SPL since 1982 on CDs, DVD-As, SACDs, and 5.1 movies.
2) Most people with normal hearing can identify the difference between stereo vs. mono bass. Stereo bass has phase for location.
3) At frequencies below 80Hz most people with normal hearing cannot isolate the physical location of the woofer. (80Hz is THX standard)
----Expert listeners can isolate location of woofers down to 60Hz by focusing on impact harmonics, port noise, upper harmonic distortion.
4) Not being able to locate the subwoofer is a good cost simplification, but summing low bass into mono degrades true stereo recordings.
5) With stereo subwoofers, any out-of-phase bass information in a true stereo (acoustic) recording is reproduced properly at full level, adding immensely to the perceived width and depth of the room in which the recording was made.
6) Irregular room shapes can have an effect on even the subwoofer frequency stereo soundstage.
7) Geddes: "The mains should be designed for the best possible direct field with as flat a power response as possible." Using the mains for Room Equalization can only make the soundstage worse.

Low-Frequency Optimization Using Multiple Subwoofers
TODD WELTI AND ALLAN DEVANTIER
INNOVATION | Harman
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Old 22nd June 2018, 08:29 PM   #67
Overkill Audio is offline Overkill Audio  United Kingdom
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Default flat to 20Hz at 104dB continuous AES (110dB peaks)

The Precision Devices 1851 driver (sim attached) is perfectly suited to your requirements.
A single driver in a small (60 litres) sealed box will give you ultra low distortion bass down to 20Hz @ 104dB continuous (110dB peaks) with the lowest power compression of any 18 inch driver I have heard..... Just 1.6dB compression at 1,000 watts AES (not audiophile RMS / music programme etc)... This is a seriously well engineered Pro driver.

5 inch voice coil, good ratio of Mms / High Bl (for a an 18 inch driver) and easily copes with the texture and detail of low mid-range.
I have used it up to 400Hz, but prefer it covering the 20Hz to 250Hz band.

You will gain an extra 6dB over and above the attached sim if you place the sub(s) in a corner.
If you need higher SPL use a pair you will gain an extra 3dB SPL, use 4 subs and gain 6dB.

These are really small 60 litre, easy to build sealed box designs.
The two key requirements are:
Lots of clean amplifier power.
Good DSP to Eq the response, allowing for room gain they typically need 15dB to 18dB of eq boost around 30Hz.

4 subs in corner locations will give you 116dB continuous SPL with 122dB peaks at 20 Hz.... Be careful... Thats hearing damage levels!

Cheers
Derek.
PS The attached sim was for another guy who was using them over the 50Hz to 500Hz band and comparing them to a Beyma 18 inch driver.
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File Type: pdf Precision Devices 1851.pdf (86.3 KB, 46 views)
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Old 22nd June 2018, 10:47 PM   #68
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Dear Derek,thanks for the info. and forgive me for further bothering you since I looked at Precision devices site and found out that the model called 1851-2 has Frequency range of 35Hz-2kHz,Fs-37Hz and Xmax-12m"m and even checked all models of PD and couldn't even a driver unit which goes down to 20Hz so it seems that I missed something serious here and my utmost apologies in advance .Hence',I'd appreciate your detailed explanation .
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Old 22nd June 2018, 10:58 PM   #69
KaffiMann is offline KaffiMann  Norway
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FS is not all-important. bigger drivers do not have problems working a bit below their resonance.
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Old 23rd June 2018, 06:27 AM   #70
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You are right regarding Fs in big drivers out ofwhich can go down beyond it's advertised data,but further down 1Hz,2Hz perhaps 3Hz ,but I wouldn't think that it can go down further 17Hz ?!
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