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Old 12th September 2008, 08:28 PM   #1
FE3T is offline FE3T  Norway
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Default 2 way + active sub in same cabinet pros and cons?

I do currently run a rather ugly looking DIY setup consisting of tweets and a pair of 8,5" Morel woofers in small sealed boxes and a pair of 12" subs in separate sealed boxes.

To get something better looking and sounding i consider several different approaches and want opinions on one of them here.

Tweeters

Midwoofers

Subwoofers

Sub amps

Box will probably be 39cm wide, 49cm deep, and 89cm tall
(Inner measures) cabinet thickness 30mm.
volume will be roughly 25L for the Midwoofer and 135L for the subwoofer, both sealed. AFTER bracing

tweets and midwoofers are planned to be placed off venter and mirrored.

Any disadvantages by doing a setup like this?
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Old 12th September 2008, 09:36 PM   #2
breez is offline breez  Finland
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One disadvantage is that the best possible location for a subwoofer, with regards to modal excitation, is likely different than the best possible location for the main speakers, with regards to imaging.
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Old 12th September 2008, 09:41 PM   #3
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The speakers in your links are the speakers that you already have in your possession correct? If so I think the biggest challenge will be joining the tweeter with the woofer.

Looking at the datasheets,

http://www.morelhifi.com/products/pdf/Hu%209.pdf

http://www.morelhifi.com/products/pd...0ET338-104.pdf

The woofer has a large dip in FR between 700Hz-1000Hz, followed by a huge peak centered at around 1500Hz (most likely cone break up modes). The tweeter looks pretty good, but it won't go much lower than 2000Hz. It would be nearly impossible to get those two drivers to join smoothly between 700Hz and 2000Hz.

I would say you would either need to go with a smaller diameter midbass, or if you already have the 9" woofer and want to use it, you would need to add a dedicated midrange (around 4-5" diameter).

The active subwoofer idea is a good one IMO. I use an active subwoofer design similar to what you have in mind. Powering the sub separately makes the crossover design much more simple and adjustable. I use a Behringer DCX2496 to control the crossover between my 2-ways and the active subs. I would not build them into one unit, because you might want to change the location of the subwoofer drivers depending on your room setup.

If you are buying all new drivers, why don't you consider Seas drivers? They are just down the road from you in Moss, and they are generally considered to be excellent values and outstanding performers.

If you don't have measurement capability and are not experienced in crossover design, why not consider something like Zaph's SR71's ? The drivers are both made by Seas (available locally), and the design has been received with excellent reviews.

Regards,
David
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Old 12th September 2008, 10:00 PM   #4
FE3T is offline FE3T  Norway
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Quote:
Originally posted by gtforme00
The speakers in your links are the speakers that you already have in your possession correct? If so I think the biggest challenge will be joining the tweeter with the woofer.

Looking at the datasheets,

http://www.morelhifi.com/products/pdf/Hu%209.pdf


The woofer has a large dip in FR between 700Hz-1000Hz, followed by a huge peak centered at around 1500Hz (most likely cone break up modes).
Regards,
David
I noticed the high frequenzy irregularities but to late too edit the post.

I dont have the drivers, but i do have a pair of very old but almost unused 8,5" Morel drivers who migth be better in a system like this.
i currently use them in the system i have now and it seems to me like they are very well behaved in the midrange.
These are paper cone drivers with a strange dustcap formed just like a tall 3" dome.

Click the image to open in full size.
Pic shows a second pair i have who looks a bit more used
They are marked Macrom 224W Integra

i think they would work just fine with the tweets in my previous post
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Old 12th September 2008, 10:11 PM   #5
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Default sub in same box

Hey Fe3t, well, i dont understand all you said you gonna do or want to do, so bear with me, try 2 port youre sub as its for home use as i understand, try a port Fq of about 80herts, it will be deep and solid,

try 2 built youre midrange in a sealed but not to small enclosure, though you dont want bass from it you want it to have a controlled slap on the mid to mid-high Fq's, i take it all these components were not from the original loudspeaker cabinet??

If not, Do you have a passive crossover for the 3way speaker system?
the point is that the bigger youre driver the slower its movement on excursion, that means that you could lose sound quality because not all youre speakers are doin wot the do at the perfect time giving you almost a delayed bass,its not very hearable but you might pick it up if it goes wrong bad.

Why i ask about the crossover is that some manufacturers actualy go the distance in the development of the crosover (braking or slowing the signal to the mid and even more to the high freq drivers) giving you a time alighned speaker system, i dont know the technical side of crosovers, but i hope you this is ok me sharing wot i know with you, good luck
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Old 12th September 2008, 10:27 PM   #6
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How are you planning on designing the crossover? Do you have frequency response measurement capability? While you could probably get away with a textbook crossover for drivers with alot of usable frequency response overlap, it will be very difficult to get a smooth response from any 8" woofer and a 1" tweeter. This is not to say it cannot be done, but you should at the very least model the manufacturers response curves to see where to start with your crossover components.

What do you think of the Zaph design I linked to? I'm sure those would sound great with a pair of 12" - 15" powered subs. They would certainly cost alot less than the Morel's (if cost is a factor to you), and honestly unless you are very good at crossover design they will probably sound better.

-David
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Old 12th September 2008, 10:34 PM   #7
FE3T is offline FE3T  Norway
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Default Re: sub in same box

Quote:
Originally posted by Darksoulslayer
Hey Fe3t, well, i dont understand all you said you gonna do or want to do, so bear with me, try 2 port youre sub as its for home use as i understand, try a port Fq of about 80herts, it will be deep and solid,

try 2 built youre midrange in a sealed but not to small enclosure, though you dont want bass from it you want it to have a controlled slap on the mid to mid-high Fq's, i take it all these components were not from the original loudspeaker cabinet??

If not, Do you have a passive crossover for the 3way speaker system?
the point is that the bigger youre driver the slower its movement on excursion, that means that you could lose sound quality because not all youre speakers are doin wot the do at the perfect time giving you almost a delayed bass,its not very hearable but you might pick it up if it goes wrong bad.

Why i ask about the crossover is that some manufacturers actualy go the distance in the development of the crosover (braking or slowing the signal to the mid and even more to the high freq drivers) giving you a time alighned speaker system, i dont know the technical side of crosovers, but i hope you this is ok me sharing wot i know with you, good luck

Ported are not my cup of tea, and to be honest, porting a 15" at 80hz???? that cant sound good, but you maybe ment 20-25 hz?

I prefer sealed with a Q below 0,7.

If you look at the pic below and imagine a chamber inside with approx 25L sealed for the midwoofer and the rest of the box aviable for the 15" subwoofer (again sealed )

The speaker are planned with an passive 2way x over betwin the midwoofer and the tweeter (as simple as possible), and a pair of plate amps for the subwoofer drivers

Quote:
Originally posted by gtforme00
How are you planning on designing the crossover? Do you have frequency response measurement capability? While you could probably get away with a textbook crossover for drivers with alot of usable frequency response overlap, it will be very difficult to get a smooth response from any 8" woofer and a 1" tweeter. This is not to say it cannot be done, but you should at the very least model the manufacturers response curves to see where to start with your crossover components.

What do you think of the Zaph design I linked to? I'm sure those would sound great with a pair of 12" - 15" powered subs. They would certainly cost alot less than the Morel's (if cost is a factor to you), and honestly unless you are very good at crossover design they will probably sound better.

-David

I must admit that i have ran the pictured Morel drivers for a long time with only a cap and a couple of resistors too the tweeters (old Morels too) no filter at all on the woofers, and in my opinion they do still sound good.

So ill probably take my chances on a tekstbook crossover, like a 6/12 db filter at 2-2,5khz
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