# Looking for new bookshelves, but I need help ...



## SQBubble (Nov 12, 2007)

Ok, heres the deal... 

I love the B&Ws, but, sometime when I feel like listening to some loud music, it doesnt get loud enough, and the midbass doesnt hit you in the chest enough, not that it doesnt, I just got that little need of wanting more dbs of midbass and instrument that perce through your chest, yet sharp and detailed, I may sound :coocoo:, but I just love *loud* detailed music. So here I am wanting a new DIY bookshelves setup that will replace the B&W 685. 

Im pretty much settled on the woofers and tweeter though, each bookshelfs will consist;

woofers: 2 SDX7 ported in 1cu.ft @35hz/3"port playing from around 30-40hz to 1800-2000hz
tweeter: Morel's Elite tweeter 338 playing from 1800hz-2000hz to the top...

My goals:
Real *High-Output* bookshelves.:hsd:
Sharp mid-bass and *detailed* sound all over the frequency range (down to 50hz) even at high output.
Warm, healthy, clear, *dynamic* and solid sound(controlled) for trance and dance music(no muddiness at all) even at high output

Now, I read that the sdx7's midrange isnt all that good, idk if its really true or if its true but isnt really noticeable. 

Now, my few questions are:

1. Will 2 SDX7 in 1cu.ft @35hz will give me some loud snappy mid-bass ?

2. Will 2 SDX7 with the Morel's ET338 blend well with each other ? 

3. Can I use some EQ to solve the midrange dip known around 800hz from some reviews I read?

4. Considering that the sdx7 is an 8ohm drive as well as the morel et338, I will have 3 8ohm drivers so that would make a final impendance of 2.67ohm... Should I worry about that?

5. If I make these bookshelves, I will need a xover, obviously, but I read alot that the pre-built PE's xover arent good, also, they are 300w max power, why's that? I will be giving around ±400-500rms to each bookshelves so if the 300w max power is really true, then I will have to make a custom xover, would someone help me plan a crossover ?

6. Finally, should I bother considering a mid-range dedicated driver?


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## BoomieMCT (Dec 11, 2006)

SQBubble said:


> Ok, heres the deal...
> 4. Considering that the sdx7 is an 8ohm drive as well as the morel et338, I will have 3 8ohm drivers so that would make a final impendance of 2.67ohm... Should I worry about that?
> 
> 5. If I make these bookshelves, I will need a xover, obviously, but I read alot that the pre-built PE's xover arent good, also, they are 300w max power, why's that? I will be giving around ±400-500rms to each bookshelves so if the 300w max power is really true, then I will have to make a custom xover, would someone help me plan a crossover ?


4. First off, what will your amp drive - 8 or 4 ohms? Since you will have a crossover the total impedence will not be all three elements in parallel. You will have roughly either 16 or 4 ohms for the woofer segment and 8 for the tweeter. You have to realize the impedence of a driver isn't flat over all frequencies and that adding a crossover has a huge affect as well. I highly recommend reading a bit more about crossover design and getting Passive Crossover Designer (free) from the FRD Consortium and playing with it for a while.

5. Pre-built crossovers rarely measure flat once hooked up. Some consideration for what drivers you are using and what enclosure they are in needs to be made - especially since you are looking to buy some decent (not cheap) drivers.


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## SQBubble (Nov 12, 2007)

BoomieMCT said:


> 4. First off, what will your amp drive - 8 or 4 ohms? Since you will have a crossover the total impedence will not be all three elements in parallel. You will have roughly either 16 or 4 ohms for the woofer segment and 8 for the tweeter. You have to realize the impedence of a driver isn't flat over all frequencies and that adding a crossover has a huge affect as well. I highly recommend reading a bit more about crossover design and getting Passive Crossover Designer (free) from the FRD Consortium and playing with it for a while.
> 
> 5. Pre-built crossovers rarely measure flat once hooked up. Some consideration for what drivers you are using and what enclosure they are in needs to be made - especially since you are looking to buy some decent (not cheap) drivers.


thanks for the reply,
My amp(crown xti1000) will drive from 2ohm to 8ohm, 275rms @8ohm, 500rms @4ohm and 700rms @2ohm. I'm thinking of getting another amplifier so I could run an active setup so I wont bother with crossovers, hence a lot more simple/less headache... But then again a good crossover might save me some money ... But I have read some stuff about crossovers, and it really doesnt seem simple.... 
And pre-built crossover is out of the question now!!!

Anyone have some answers about the other questions?

thx again


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