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Cover for 8" mid driver
Cover for 8" mid driver
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Old 10th June 2021, 10:54 PM   #1
Vintage Audio Projec is offline Vintage Audio Projec
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Default Cover for 8" mid driver

I am looking for some back covers for 8" mid drivers.
They used to be easy to get but the only one I can find is the VM30 from beyma but that's for 5" drivers.

Does anyone have an idea if these still exist and where to get them?
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Old 11th June 2021, 02:43 AM   #2
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speaker backbox: speaker backbox - Google Search
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Old 11th June 2021, 10:27 PM   #3
system7 is online now system7  United Kingdom
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I found this extremely interesting!

Clearly the 5" Beyma VM30 is alive and well.

VM30, 5″ back plastic cover | Beyma USA

Beyma : Beyma VM30 :: PS4.40 IN STOCK (11 Jun 2021)

The 8" VM10O is clearly dead in the water. Discontinued.

I have a use for the VM30.
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Old 12th June 2021, 08:11 PM   #4
Vintage Audio Projec is offline Vintage Audio Projec
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Indeed the VM100 is discontinued and I am looking for something like this.

A google search didn't came up with that much.
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Old 12th June 2021, 09:09 PM   #5
system7 is online now system7  United Kingdom
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If you had followed GM's google search, you might have come up with something.

speaker backbox - Google Search

Problem for us, is you are quite shy about telling us anything, which affects local availability. I have no idea where you live. I have no idea what your level of ability is.

Generally speaking, an 8" woofer needs about 20L volume (metric), or about 1 cubic foot (Imperial):

Click the image to open in full size.
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Old 12th June 2021, 09:14 PM   #6
Vintage Audio Projec is offline Vintage Audio Projec
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I live in belgium and it's for a mid speaker

I have used the VM100 in the past on some beyma 8MI100 and the like.
So a really small back chamber for an 8" mid.

Found something that could be usefull on parts express but have to check the exact measurements if it will fit.
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Old 12th June 2021, 09:54 PM   #7
system7 is online now system7  United Kingdom
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Doubtless, the reason Beyma disconitinued the VM100 was it was pointless!

Whyever would a reasonably sane person use an 8" as a midrange?

This is how you do it:

Click the image to open in full size.

Classic monitor designs?
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Old 12th June 2021, 11:44 PM   #8
Vintage Audio Projec is offline Vintage Audio Projec
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Srry to say but you should look up some PA designs.

An 8inch can be used to 1.5kHz without beaming problems and have a reasonable sensitivity.
When using an 15" bassmid driver, crossing over to a compression driver is difficult and far from ideal. The 15" driver starts to have beaming issues at a frequency that is to low to cross over to the compression driver. I like to use 1" exit comp drivers as they will sound a lot nicer on top.
2" inch can be used and crossed lower but sound harsh and ugly most of the times.
Most people use 2way designs as it's easier on crossovers and cheaper but if you need to get the vocals load and clear it doesn't work for me


When a 12" bassmid driver is used it's better but stil not ideal.

The best solution is to go 3way.
Don't skimp on the mid as the basic musical information comes from this in a normal loaded speaker. (there are some horn's etc that use different approaches...)

When Using 15" bassmid drivers that have high sensitivity (around 100db/2.83v/m etc) I like to use an 8"mid. There are very good 6.5" drivers but sometimes it's just not enough or you need to horn load them but a good horn that extends high enough will probably need a phase plug etc....

When Using 12" bassmid drivers I would use 6.5 inch mid drivers.



Just to name a few 8" dedicated mid drivers.

B&C 8PE21
18sound 8M400
Beyma 8MI100
RCF MR8N301 (it has a closed back by design already they even have the 10" MR10N301)


Most of them can be used from around 100-200Hz to around 2khz max
the 8PE21 is really good


This is also interesting reading high-efficiency_midrange-drivers


So using an 8inch mid is a sane idea i would say....

I did use the google search from GM and have found some things but in general it's more difficult to find then some years ago
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Old 13th June 2021, 02:34 PM   #9
system7 is online now system7  United Kingdom
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Fair enough!

What glue do you use for sticking chipboard to the plastic back? Epoxy?

Will order a couple of VM30 backs for my fullranger Markaudio CHN50 tweeters. Looks ideal.

CHN-50 full range driver | KJF Audio
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