New to ms8......question or 2

[AcMekanik]

So far, I have nothing but good things to say about the ms8. I have always tried to shoot for sq in the systems I had over the years but they were half assed builds at best. I really wanted to go in an educated direction this time and after all the reading I had been doing on the ms8, when one popped up on the bay for 325, I couldn't say no.

The question I have is this. I bought some c5-075ct Jl tweets a while back before the ms8 and used the inline xo included with them. My sound up front is much better with the dsp but the inline crosses at 12db/oct. @ 4khz on the tweets. I left the xo at 3500khz during setup on the ms8 figuring it isn't making any diff. because of the passive inline. How much benefit would I see removing the passive and allowing the dsp to cross them and what would I need as a prot. cap on those tweets? I know I can never be happy with my **** and always have to screw with stuff so I am wondering should I leave well enough alone. Would it make that much of a diff crossing at 24db/oct vs. the passive 12db? The point would prolly stay pretty close to the same at 4khz. Does changing the xo points on the tweets make that much difference to the front stage?

I had thought about running a center but if its just me most of the time, will a center be that much of a benefit?

If I try running a center, I don't have anywhere on the dash to mount a center (03 f150) unless I made a small enclosure to sit on the hump in the middle of the floor up against the lower part of the dash. I just feel like that would be a waste of time since its so low down on the floor.

I had been considering bringing up the tweets higher in the door panels but right now the stage isn't bad and everything is hidden behind the door panel in the factory speaker. It would be nice to have the stage brought up higher on the top of the dash. Right now, it seems like everything is even with the door panels. The width is good, separation of each instrument/player locations is great, the bass has a good feel of coming from the front as long as I'm not playing something like rap and whatnot. I think there is room for improvement but it seems counterintuitive placing a speaker on the floor when I'm trying to bring the stage up higher. Is the ms8 a miracle worker in that regard? I think that's asking a bit much.

One more thing. I saw in another thread somewhere that there is a guide of some sort for the eq as to what bands can be manipulated in order to adjust staging. I saw something mentioned but it never went any further into it.

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[gimling]

putting a cap on the tweet is the same thing as a passive crossover just a cheaper setup. If you have your tweets run independantly on there own amp then just use the MS8. As far as raising your stage I have 2010 f-150 i added a second set of tweets high in the pillar and crossed them at 8k for ambient which atm has the stage just outside my front window bout a foot up from the hood.

your crossover roll off is just different style of filters and without an RTA its going to be hard to get perfect but having the ms8 where it is the passive is going to knock out what the ms8 is letting through, you want the same roll off filter that you have on the mids. without going into much detail crossover points between mids and tweets with same roll off per octave is how you determine your roll off and crosspoints, the higher the roll off the closer you want the cross points because your cutting sound from the tweet and mid at certain points say 2.5k on your mid with a 12db per octave and 4.5k on your tweet with 12b peroctave your mid and tweet are playing both playing 2.5khz to 4.5khz at a lower db which together should bring it to a 0db level. (its much more technical but easiest way to explain it).

As far as your stage, are you using the autotune of the MS8 or are you adjusting it manually?? I dont use the MS8 i use a 32band eq parametric eq and time delay to set it myself, I never really liked the way logic processing sounded but others swear by it.

and for center channel speaker if you do use the logic processing the more the ms8 has to work with the better its processing.

 

[AcMekanik]

putting a cap on the tweet is the same thing as a passive crossover just a cheaper setup.

I had in mind something around a 40uf just as a safeguard against any "mishaps".

I am using the autotune and it has done a great job so far but can still use some tweaking.

I am running the L7 with the rears and it has just the right amount or ambience when set in the driver setting without pulling to the rear or taking away from the fronts.

I haven't really messed with the eq much as I haven't really had to yet as nothing seems that far out of whack. Just saw somewhere that if you boost/cut some select bands they can move out/bring in or bring up/lower the stage a bit. Havent screwed with it. It is the internal 31 band in the ms8.

 

[gimling]

if you want to protect it from overpowering it you can put in a fuse inline, I guess u could use the cap if u wanted to, usually if a crossover is going to fail the crossover blows and nothing will get to the tweeter

 

[LosIsATool 5,000+ posts]

You don't need a cap on the tweeter. The ms-8 will level match everything.

 

[AcMekanik]

I guess since I have always had something on the tweeters before that its a bit out of my comfort zone having them wired strait to the amp. I guess aside from being driven into complete clipping which I cant see happening with this setup so far, I really don't have much to worry about.

I guess the reason for my concern is that I have a slight pop when the amps power down. Its not really loud or anything but I was concerned about that kind of stuff damaging the tweets. Any reason I should be?

 

[gimling]

if its popping you may have a bad ground, small possibility of a bad component in the amp, could try a ground loop isolator from radio shack just to check, and or check where your grounding. if you are concerned about protecting the speakers put an inline fuse on one side of the speaker wire,

 

[AcMekanik]

Alright, cool fellas. I appreciate the replies. If I can eliminate the noise on shutdown I don't really see a need for anything inline.

 

[TaylorFade 10+ year member]

Lose the cap. Let the MS-8 do it.

Centers are more for two seat cars and can smear the image since you will get L+R information from the same spot, but the MS-8 does a great job at it. I just don't think it's worth the extra amp channel- especially since the MS-8 is going to align everything to your seat anyway.

Stage height is created by actual physical location of the HF transducer. This is why we put tweeters in the pillars or sail panels.

The only way you can manipulate the "stage" with the MS-8 is to retune with different head positions until you find the one you like.

 

[LosIsATool 5,000+ posts]

Alright, cool fellas. I appreciate the replies. If I can eliminate the noise on shutdown I don't really see a need for anything inline.

Are you running all remotes off the MS-8? You should be.

 

[trumpet 5,000+ posts]

How much benefit would I see removing the passive and allowing the dsp to cross them and what would I need as a prot. cap on those tweets?

Allowing more sound to play through the tweeters may help raise your sound stage if the tweeters are mounted higher than the woofers, plus you might find there is a bit less of a difference in sound as you move your head around. I recommend using a non-polarized electrolytic capacitor with a value that will result in minimal effect on the sound, meaning it will act as a crossover below the range you define with MS-8. If it's a 4 ohm tweeter then a 22 uF 100V capacitor is a good choice.

Passive Crossovers, Capacitor and Coil Calculator

Would it make that much of a diff crossing at 24db/oct vs. the passive 12db? The point would prolly stay pretty close to the same at 4khz.

The crossover type that MS-8 uses on the 24 dB/oct setting will result in two adjacent speakers having flat phase and no bump or null at the corner frequency. This is a good thing, and you should use that instead of the 12 dB/oct passive crossover. Because the roll-off is twice is fast, it will cut power twice as quickly, meaning you can also select a lower frequency. 3 kHz is probably safe with these tweeters.

I had thought about running a center but if its just me most of the time, will a center be that much of a benefit?

I've gone through the trouble of cutting my dash and building a pretty great sounding center channel in my 01 Saturn sedan. I think it was worth it when I had MS-8, but for 99.9% of people riding alone that would be too much trouble for little gain. It depends on what kind of recordings you listen to, and the benefits of Logic 7 basically go to waste with a lot of pop music that's mostly mixed in mono.

I had been considering bringing up the tweets higher in the door panels but right now the stage isn't bad and everything is hidden behind the door panel in the factory speaker. It would be nice to have the stage brought up higher on the top of the dash. Right now, it seems like everything is even with the door panels. The width is good, separation of each instrument/player locations is great, the bass has a good feel of coming from the front as long as I'm not playing something like rap and whatnot. I think there is room for improvement but it seems counterintuitive placing a speaker on the floor when I'm trying to bring the stage up higher. Is the ms8 a miracle worker in that regard? I think that's asking a bit much.

Don't put a speaker on the floor. Try temporarily moving the tweeters to the top of the doors or to the sail panels. You can use tape before you decide to permanently mount them.

One more thing. I saw in another thread somewhere that there is a guide of some sort for the eq as to what bands can be manipulated in order to adjust staging. I saw something mentioned but it never went any further into it.

I advise staying away from any traditional or old school tuning tricks. You have a very powerful DSP that wants to tune your system to a very good response curve. If you want to adjust the EQ do it to fix response problems, either something you find with an RTA or to target some annoyance that needs to be tamed. Move the tweeters up. They don't have to go above the dash.

 

[AcMekanik]

Thanks Trumpet, that's the answer I was looking for concerning using capacitors for tweeter protection. I just didn't know what size to go with.

One question, concerning those CDT HD-6CF.2 I got from you guys, it says on the included spec. sheet that they have a freq. response up to 5khz. Is that realistic and if so what should I then cross those JL C5 tweeters at? You had suggested crossing them at 3khz with the ms8 24db/oct. Is that a recommendation based on the fact that I am using those CDT's?

 

[trumpet 5,000+ posts]

One question, concerning those CDT HD-6CF.2 I got from you guys, it says on the included spec. sheet that they have a freq. response up to 5khz. Is that realistic and if so what should I then cross those JL C5 tweeters at? You had suggested crossing them at 3khz with the ms8 24db/oct. Is that a recommendation based on the fact that I am using those CDT's?

Yes, it is realistic to expect HD-6CF.2 to play up to 5 kHz. However, with the speakers mounted in doors facing the interior of the cabin the response is likely falling off rapidly beyond roughly half that value, 2.5 kHz. The actual results are only known by making certain acoustic measurements in your vehicle. The 3 kHz crossover suggestion is a compromise between getting better sound overall from the woofers and tweeters and protecting the tweeters when you play the system very loudly.

 

[AcMekanik]

Thanks for the reply. I finally have a bit of time tonight after work so I'll pull those passives and set the tweets per your recommendations and see how it sounds.