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View Full Version : 6.5 to 8" midbass, will i need another mid?



lostsoul
08-19-2005, 12:58 PM
Hey guys the mids on my Oz ME's are getting a little worn so i figured it was time to try something new. I want to go up to either a 7 or 8 inch midbass. Now my question is with running only an 8" and a tweet will I loose alot in some of the frequency ranges? Will i have to add like a 4" and go threeway? Thanks guys.

JAZN
08-19-2005, 01:00 PM
depends on the particular mid. many 7s can play in 2way with ease, along with some 8s, while others u need to throw in a midrange.

lostsoul
08-19-2005, 01:01 PM
Im looking at the kicker resolutions or the kicker SS 8s.

squeak9798
08-19-2005, 01:02 PM
Very speaker dependent. Some (very few, but some) tweets will play down to 1500hz. Other struggle if going below 3khz. Likewise, some 8's will handle playing up to 2.5khz, others don't like playing above 500hz. Just depends.

Likewise, another thing to take into consideration is beaming issues. A large mid, like an 8", playing very high will start getting into beaming (where the off axis response becomes extremely poor and basically non-existent). This will kill your imaging and tonal quality.

lostsoul
08-19-2005, 01:03 PM
so really its not a good idea? lol

audiolife
08-19-2005, 01:04 PM
get a sync8!!! lol

squeak9798
08-19-2005, 01:05 PM
so really its not a good idea? lol

It can be done. DLS, Morel (I think) and Memphis all make component sets that consist of only an 8" mid and a tweeter.

You just need to be very wise in speaker selection and setup.

Talk to 3.5Max6spd also, he just got done doing a DIY 8" mid + tweeter comp set. He may have some more insight on this.

lostsoul
08-19-2005, 01:14 PM
well heres a link to tweeters i have:
http://jti-innovation.com/oz/oz_prod_matrix180.htm#180cs

Mids Im looking at:
http://www.epinions.com/Kicker_8__Mid_Range_Speaker_02RMB8__Midrange_Speak er_02RMB8/display_~full_specs

squeak9798
08-19-2005, 01:15 PM
General rule of thumb is to crossover the tweeter no lower than twice it's Fs.

OlogyAudio
08-19-2005, 01:25 PM
Hey guys the mids on my Oz ME's are getting a little worn so i figured it was time to try something new. I want to go up to either a 7 or 8 inch midbass. Now my question is with running only an 8" and a tweet will I loose alot in some of the frequency ranges? Will i have to add like a 4" and go threeway? Thanks guys.

what do you mean a little worn???

Anywho -- it all depends on what 8" midwoofer -- and what tweeter we are dealing with -- there are some insane tweeters that can take punishment -- and some 8s that can still be used upto 30 degrees off axis if crossed low enough -- and don't have nasty breakup modes to deal with... You would be better off getting a nice 7" midwoofer that doesn't require a mid... just a very robust tweeter is again required... There are a few that come to mind that don't cost an arm and a leg... Dayton RS -- Seas TDFC -- Seas TBFC -- and there is a vifa XT that is good enough as well -- I'm sure there are more but those are the ones I'd pick from... Now there are loads of nice 7" midwoofers... see this for a few examples:
http://206.13.113.199/ncdiyaudio/mark/Testing/Woofer4/Seven_inch_midwoofers_blowout.htm

oh ya and whats your budget? -- I would assume you are going active? So I would have to say one of the scans would be your best bet....

If you high pass 4th order a 2khz xover point may work out fine for you with your current tweeter -- in which case a scanspeak 7" would do the job but cost a little bit of money...

audiolife
08-19-2005, 03:34 PM
kicker rmbs arent too great above 500 hz 1khz tops .

squeak9798
08-19-2005, 04:09 PM
:word:

Those were really more of a midbass.

3.5Max6spd
08-19-2005, 04:22 PM
8's in a 2way are tough....

be ready to dedicate massive sound deadning to your doors and door panels. The midbass impact alone can add resonance and further take away from midrange and its overall 'depth' of the fronstage.

you need a decent amount of EQ prowress and flexible xovers to thin out some areas in the freq range as well as integrating the rolloff into each other- without this dont expect great SQ, its a must in a car DIY application..

There are quite a few with good midrange capability (up to 2.5-4khz) 8's out there .
Morel (wr8, hcw8, mw267, mw265,H8.1....), Illusion nd8i's, Dyn 170....

Best of luck.

OlogyAudio
08-19-2005, 05:00 PM
8's in a 2way are tough....

be ready to dedicate massive sound deadning to your doors and door panels. The midbass impact alone can add resonance and further take away from midrange and its overall 'depth' of the fronstage.

you need a decent amount of EQ prowress and flexible xovers to thin out some areas in the freq range as well as integrating the rolloff into each other- without this dont expect great SQ, its a must in a car DIY application..

There are quite a few with good midrange capability (up to 2.5-4khz) 8's out there .
Morel (wr8, hcw8, mw267, mw265,H8.1....), Illusion nd8i's, Dyn 170....

Best of luck.
What he said but just to elaborate...
I wouldn't lowpass ANY 8" over 2khz... I'd try to cross atleast 1/2 an octive below where the linear ditortion figures get crummy... if you can that is... also the power response will be too uneven -- not to mention very few have good linear distortion past 1.5khz... and almost none have even reasonable linear distortion figures over 2khz... -- you want a SHARP corner -- I would suggest getting a very capable tweeter and crossing over as LOW as possible... :)