Door project and 3 way active

[///M5 2,833]

Can't recommend anything without knowing what you have for processing. As I stated above that could EASILY make some setups impossible.

Sorry, I forgot to address the 5L question. It isn't enough for a 4" er, more or less something bigger. IB is going to be what you'll need to do.

[stiffler style 9]

It's not overwhelming. I didn't know how in depth it would be. I like the challenge.

I have a active capable headunit (sub, mid, high) with time alignment and a 5 band parametric eq.

Ib it is.

I have an idea for the "baffle" for the midbass as well. I will make it out of mdf rings but mount it to some sort of insulation foam or something to decouple it from the inner door metal to reduce vibrations and then add a ton of mass to the baffle. How does that sound?

Edited October 21, 2012 by stiffler style

[///M5 2,833]

Decoupling is great, the only trick is to maintain the seal

Active capable headunit's all have limitations as well. For instance, good luck using only the crossovers on a Pio 880/800 for running a 2 way with a FR driver. The cross points aren't flexible enough. There are some that even have limitations that can make tweeter integration tough. There is a reason I asked for the model you have, but knowing the cross points and slopes would even be better.

[stiffler style 9]

Clarion cz702

Straight from crutchfield.

• Time Alignment: select 0-501.4cm for Tweeter L/R, Midrange L/R, and Subwoofer L/R speakers
  
• Tweeter HPF: select cut-off frequency for high pass filter (25Hz/31.5Hz/40Hz/50Hz/63Hz/80Hz/100Hz/125Hz/160Hz/200Hz/250Hz/315Hz/400Hz/500Hz/630Hz/800Hz/1K/1.25K/1.6K/2K/2.5K/3.15K/4K/5K/6.3K/8K/10K/12.5K/16K/20K/Through), Slope (-6/-12 dB), Phase (normal/reverse)
  
• Midrange HPF/LPF: select cut-off frequency for the high pass filter (25Hz/31.5Hz/40Hz/50Hz/63Hz/80Hz/100Hz/125Hz/160Hz/200Hz/250Hz/315Hz/400Hz/500Hz/630Hz/800Hz/1K/1.25K/1.6K/2K/2.5K/3.15K/4K/5K/6.3K/8K/10K/Through), select cut-off frequency for low pass filter (630Hz/800Hz/1K/1.25K/1.6K/2K/2.5K/3.15K/4K/5K/6.3K/8K/10K/Through), Slope (-6/-12 dB), Phase (normal/reverse)
  
• Subwoofer LPF: select cut-off frequency for low pass filter (25Hz/31.5Hz/40Hz/50Hz/63Hz/80Hz/100Hz/125Hz/160Hz/200Hz/250Hz/315Hz/400Hz/500Hz/630Hz/800Hz/1K/1.25K/1.6K/2K/2.5K/3.15K/4K/5K/6.3K/8K/10K/Through), select cut-off frequency for the high pass filter (16Hz/20Hz/25Hz/31.5Hz/40Hz/50Hz/63Hz/80Hz/100Hz/125Hz/160Hz/200Hz/250Hz/Through), Slope (-6/-12 dB), Phase (normal/reverse)
  
• Speaker Gain: select -20 to 0dB for Tweeter, Midrange, and Subwoofer
  

Should I look to decouple the speaker from the baffle as well?

Edited October 22, 2012 by stiffler style

[///M5 2,833]

Awesome. I wouldn't have known the 702 specs off the top of my head. Pretty sweet they don't jack you on the low end for the tweet/mid HP. Allows a pretty reasonable choice for doing things Obviously more than the third octave choices would be nice and more slope choices, but at least you can actually have some flexibility. Electronic phase is nice for setting things up too. Enough flexibility to do what you need in a 2 way. 3 way would be tough as integration with an amp as well will be frustrating.

I'd rather decouple the larger mass if I could and there is no huge reason to do both.

[stiffler style 9]

I was kind of hoping there would be flexibility with the choice for 24db slopes too but I'll make due with what I have.

So now that we've covered processing. What's the next step?

[///M5 2,833]

You said large format in the door, how about small format?

[stiffler style 9]

If I can fit large format then surely I can fit small format. Are there any t/s parameters I should specifically consider when looking at tweeters? If there are, what range of values should I look for?

I would think fs would be important here as this has to meet up with a midbass.

[Impious 1,476]

General rule of thumb is that the Fs should be half of the frequency at which you intend to cross the driver. Obviously reality isn't as cut-and-dry as that, but it's a good rule of thumb to think about when scrolling through tweeters looking for options. I.E. if you want to cross around 2khz to mate up with your mid, you would want a tweeter with an Fs in the vicinity of 1khz.

[StreetLegal 119]

General rule of thumb is that the Fs should be half of the frequency at which you intend to cross the driver. Obviously reality isn't as cut-and-dry as that, but it's a good rule of thumb to think about when scrolling through tweeters looking for options. I.E. if you want to cross around 2khz to mate up with your mid, you would want a tweeter with an Fs in the vicinity of 1khz.

Very informative rule of thumb, I would appreciate if you can explain why.

Sorry op, not thread jacking or anything but I am sure you would also be curious to know.

[stiffler style 9]

General rule of thumb is that the Fs should be half of the frequency at which you intend to cross the driver. Obviously reality isn't as cut-and-dry as that, but it's a good rule of thumb to think about when scrolling through tweeters looking for options. I.E. if you want to cross around 2khz to mate up with your mid, you would want a tweeter with an Fs in the vicinity of 1khz.

Very informative rule of thumb, I would appreciate if you can explain why.

Sorry op, not thread jacking or anything but I am sure you would also be curious to know.

We're all here to learn anyways so I'm happy you asked. I'm curious as well.

[Impious 1,476]

First it's to ensure adequate protection against over-driving and potentially damaging the tweeter.

Second, generally speaking distortion is lower and frequency response is smoothest outside of the range of around an octave or two above of Fs.

This obviously depends on the specifics of the tweeter itself and the intended crossover slope as well; a shallower slope would need to be crossed higher than a steeper slope.

[stiffler style 9]

"a shallower slope would need to be crossed higher than a steeper slope."

Are there any specific instances when using a shallower slope and higher crossover is better than a steeper slope and lower crossover and vice versa? Does one "blend" better than the other setup?

[///M5 2,833]

If I can fit large format then surely I can fit small format.

I meant up higher with the small, ie in the sails or something. You alluded to that earlier.

"a shallower slope would need to be crossed higher than a steeper slope."

Are there any specific instances when using a shallower slope and higher crossover is better than a steeper slope and lower crossover and vice versa? Does one "blend" better than the other setup?

Please don't type in black, most of the mods and regulars use a black background making us have to highlight to read.

Steep slopes are the most effective at protecting the drivers. Steep or shallow can blend better depending on the install and driver separation. In transition areas you'll have to experiment. When I can get it to work I generally prefer shallower slopes, but that is a when. Be careful as you experiment because if you test your drivers and when they start to get nasty with a steep slope they'll do it earlier with a shallow. Different slopes will require different cross points as well. Mixing slopes can also be beneficial sometimes.

If you end up mounting everything in the doors, it'll be a bit of a crapshoot depending on the off axis response of the drivers in the frequency range. Generically the goal is to pick cross points that are safe and allow you to manipulate the slopes such that the drivers sum nice and flat in the transition region.

[Impious 1,476]

"a shallower slope would need to be crossed higher than a steeper slope."

Are there any specific instances when using a shallower slope and higher crossover is better than a steeper slope and lower crossover and vice versa? Does one "blend" better than the other setup?

Generally in car audio it's more because of equipment limitations. But there could be specific situations where a shallower slope works better due to the frequency response characteristics of the installation/drivers/vehicle, phase response, etc. Generally speaking I would start with the steepest slope available and see if I could obtain the desired response. If not or there are problem areas around the crossover point, I work backwards from there.

[stiffler style 9]

There are tweeters in the sails. They are 25mm. As far as I know they are on axis too.

I not quite understanding what I did for it to appear in black. I'm not seeing any change. I did copy and paste from Impious' post.

Now what about overlapping frequencies? Say the midbass rolls off hard at 2khz and the tweeter can effectively play down to 1.6khz. Do I cut the midbass at 1.6khz and high pass the tweeter at 1.6khz also or do I overlap? I would think overlapping would be negative towards sound quality.

I understand that doing a 2-way specifically in the doors isn't going to have a nice response, but I'm definitely willing to experiment with it and the sail panel. If I did indeed try a 2-way (door only) would I just be loosing the top end?

[///M5 2,833]

Again, it'll depend on a lot of factors. The drivers FR, the mounting location and axis, and of course what frequencies you can choose and their slopes. In a perfect world when the drivers are nearly coincident underlapping is better, but sometimes in a car the compromises you made in the install require an overlap situation. Anyone who thinks it's a one size fits all scenario is wrong.

Your "negative" towards SQ is true IF the sum of the frequency response from both drivers in the cross band is above the nominal line. If they blend with an overlap then it's a positive.

I seriously doubt those 25mm are on axis...could be, but that isn't so normal. And if so, you may not want to go that route. Depends on the car and their location. I'd pull them apart and see what you can fit up there before deciding.

[stiffler style 9]

I'll check out the tweeter locations tomorrow and see what I can do with that area.

If I'm following you correctly, I should determine the mounting location for the tweeter (door or sail panel) then find a tweeter then choose a midbass. Is this correct?

[///M5 2,833]

Mounting locations first and then assemble the options you have for both drivers. Considering you don't have a ton of experience running active for the midrange I'd suggest something without nasty breakup modes. Something with a smooth response will help. As an example of a mid that'll blend with about any tweeter and still has rompin' midbass for it's size the Seas ER18 is a great example. Check out it's FR and such and compare with what else you are looking at.

[stiffler style 9]

What affects breakup modes? Does the cone material have any affect on it or how a driver would sound?

Funny you mention that driver as I have it pulled up on another tab from a couple days ago.

[StreetLegal 119]

How about this http://www.madisoundspeakerstore.com/scanspeak-woofers-6-7/scanspeak-discovery-18w/4434g-00-7-midwoofer-4-ohm/

or this set ran active http://www.madisoundspeakerstore.com/auto-kits/scanspeak-6.5-2-way-signature-car-audio-kit/

I also want a 2 way active front stage with the most midbass that I can get and was looking at the scans, which gives tweeter options for on or off axis. Its pricy, but I would like to hear m5 and the other tech's opinion.

Also, op might be interested as well.

[///M5 2,833]

It isn't funny that I picked the ER. It is a super forgiving driver that excels in a 2 way. Great bottom end with some nice midrange as well.

And yes, cone material is exactly what typically causes the resonance modes. Fancy cones have audible breakup usually in the lower tweeter range. Obviously if they are high enough up it can be okay, but if the mode has 10dB of gain and your crossover only has it down 6dB you have 4dB of gain where you were expecting a roll off. A notch filter can pull it out completely, but those aren't usually available in a headunit and making one from analog components while not hard is probably beyond the scope of what you want to do.

How about this http://www.madisound...idwoofer-4-ohm/

or this set ran active http://www.madisound...-car-audio-kit/

I also want a 2 way active front stage with the most midbass that I can get and was looking at the scans, which gives tweeter options for on or off axis. Its pricy, but I would like to hear m5 and the other tech's opinion.

Also, op might be interested as well.

Don't take this the wrong way, but buying that Scan set would be absolutely STUPID if you were running active. A good portion of its cost is in the crossovers and you wouldn't be using them. I also haven't had the best luck with ~7" Scans run in a car door. The Seas do a better job. If it were a 4" mid, then kiss that statement goodbye, but the OP needs a 7 not a mid.

That comp set you linked highlights something though that ALL car audio comps suck at....having good crossovers. In general you should figure nearly the same money for drivers and crossover components. So yeah, complete waste to buy a comp set and run it active, but at the same time most car audio sets have a crossover I could build for less than $30 and regularly way less. Now perhaps you know why they all pretty much suck. This doesn't even take into account the compromises they make to make the drivers cheaper in quantity either. Not a single set on the market right now that I like for the money.

[stiffler style 9]

Funny as in ironic that I was looking at the same driver you recommended I take a look at. I looked at the frequency chart and it does seem like it can play high enough to work with a tweeter. Is the best way to look at resonance modes by looking at frequency charts?

The qts is .32. Is that going to have any noticeable affects on the speakers ability to play in a door, considering the door is sealed as best as possible?

[Impious 1,476]

It can show up in a frequency response graph, but cone breakup can also show up in the impedance curve. A "wiggle" in the impedance curve with a corresponding "wiggle" in the FR usually indicates a resonance mode. For the Seas ER18RNX that peak in the FR around 4.5khz is cone break up related....which is good as that's pretty high for a 7" driver.

Qts without Fs doesn't tell us much with regards to frequency response. An Fs of 37hz is pretty low...which isn't bad, IMO better than a higher Fs with a Q that low being ran IB in a car door. Subjectively it's going to depend on your taste. You're not going to have the "bump" in midbass output like a higher Q/higher Fs driver would, but it's roll off will also be more shallow and extended.

[stiffler style 9]

Ah okay. This is really helping me interpret drivers and compare now.

I've read some very good reviews of the B&C 6NDL38. It's bit a different than the Seas driver... I think.

Both 8 ohm. The Seas driver has a smoother rolloff. The B&C driver has steep rolloff around 4khz with a slight wiggle in the impedance curve at 1.5khz and 3khz. Same xmax for both drivers. The Seas has 4cm^2 more sd than the B&C. The B&C is rated to handle almost twice the rms power (Is that applicable at all for my application?). The Seas has 88.5db efficiency compared to the 92db efficiency of the B&C. Seas fs = 37hz. B&C fs = 72hz. Seas qts = .32. B&C qts = .42.

That's what I gather that matters from comparing the drivers based on specs. It looks like the B&C would have better midbass output in the car door while still retaining a good, useable frequency range to pair with a tweeter. The biggest difference I see is the low fs/low qts of the seas and the high fs/high qts of the B&C. When is low qts/fs better than high qts/fs and vice versa? What am I missing here in comparing the drivers? Is there something else that I should consider?

Of course, the price is different as well but I'll leave that to the side for now.