Im just curious as to what people have their crossover points and slopes set on for front stage, and sub....

tweeter 1.5kHz and up
midrange 500Hz to 1.5kHz
midbass 50Hz to 500Hz
sub up to 50Hz

approximately

acoustic crossover differs slightly from electrical crossover.

interesting that you tweeters run so low,

hae you tried running just two way???

On my system (Dynaudio MD-130 tweeter and MW-160GT woofer): 2300Hz, 12db/octave slope.

Lower cross over points for tweeters in cars is a great way to improve stage and image.

First, tweeters are much easier to mount high in the car and easier to adjust positioning than woofers. Lower tweeter XO means more bandwidth being dispersed where it’s needed. Lower XO points for tweeters needs they need to handle more power. For this reason higher orders or slopes are used. It is very important to remember that with tweeters going below recommended points and slopes means lower power handling. If you go to low you will burn the tweeter.



Cross over points and slopes are difficult to generalize. Each system should be evaluated individually. Things like positioning, power, power handling, size, type etc all play a role in what works best.



IMO mid bass upper XO points need to be below 300Hz. This is the point at which we begin to hear stereo and it makes sense to me keep all audible stereo information coming from the mid range and tweeter.

Your tweeter XO can be anywhere from 500Hz and up.

Lower mid bass and sub XO anywhere from 50Hz to as high as 250Hz.



Always keep XO points at least 1 Octave away from the speaker Fs {Free Air Resonance}

Cheers

yep, midbass are too far off-axis, so need to 'fill' the midrange.

might run the mids down lower - trying some things at the moment

On my system, the electrical XO points are:

Tweeter: HPF at 5 kHz-18dB/octave
Midbass: HPF at none (using the driver's natural roll-off) - LPF at 1.6 kHz-12dB/octave
Sub: HPF at 40 Hz-18dB/octave

Cheers,

Bon

Tweeter HPF 3.2khz 12db (on Axis)
Midrange LPF 3.2khz 12db
Midrange HPF 315khz 12db (on axis)
Midbass LPF 315khz 24db
Midbass HPF 71hz 6db (speaker off axis)
Sub LPF 80hz 24db
Sub HPF 20hz 24db

Juls

yes, but what i was getting at is, if he ran hes midwoofers up higher, and put them on axis,



or alternately, run your midranges down to below 300, and up to 7-8khz, this would make it easier to get a nice image as most of the cues would come from on driver...

it's hard to gt a speaker working well over such a large frequency range, but then I have seen an 8" that does 100Hz to 15k quite ok.

I am angling the midbass for the next comp, so will see how it goes.

Tweeter: HPF 3.15KHz @ 12db
Midbass: LPF 1.25KHz @ 12db
Midbass: HPF 100Hz @ 18db
Sub: LPF 63Hz @ 18db
Sub: HPF 25Hz @ 18db

hey car1990, whats going on with the lack of frequncies not covered by the tweet or midbasss???or do you find that the slope is not so steep that it cuts them out completely???

Somehow the gradual slopes at 12db on both sides are just nice for my car enviroment. I persume when people cutoff at same frequency on both sides, they are basically overlapping a certain portion of frequency spectrum no matter how steep the slopes are.

Acoustic (eg. Passive) crossover points are at -3dB of speaker response. So when two speakers overlap the same frequency, they increase the volume at that point by 3dB, and hence producing a flat curve (or a line ). Electronically (ie. active) its different (I think). The Xover point is the rollover point.


And I was also surprised to see your Xover points. However, if that works for you, fantastic

simon i wouldnt use 1.5khz even with 24db/oct on the xt tweeters. Tweeters even with 750hz fs dont like going that low. Yes the f/r graphs show a lot of low fs tweeter that manage flat down to 1khz. However it doesnt take into considderation travel vs frequency or thd. Voice Coil magazine did a review on the tlr focal tweeter when it came out. IT could go easily down to 1khz flat. But the testers found that it in real life the tweeter just couldnt do this. THD and the larger movement of the cone just didnt make it practical. By using a higher x-over point on the tlr the tweeter was smoother and less distorted in the lower octaves. I think from memory they suggested 3khz and over for this particular tweeter.

You will find with passive x-over designers that they dont usually go below 2khz for any tweeter unless its bigger than 28mm.Yes i know you use active setup but the same principles remain, try and go as low as possible without sacrificing too much power handling and try not to increase THD. Then you have to match it with the mids.... If you can have a listen to the system using 2 - 2.2khz x-over with 18 or 24db/oct slopes and let us know if that is an improvement using normal listening levels or above levels. Since your mids and tweeters are located in the kicks (if i can remember) you dont need to push those xt tweeters so hard. 6.5inch mids start to stuggle @ 3khz and above so 2khz would be a very nice compromise. You know that all fibreglass and carbon fibre cones have massive breakup nodes around 5k -12khz. Ive read a few articles on this and it seems to get the best out of this type of cone or a metal cone you must notch filter (or eq) the on axis breakup nodes even when they are totally out of band. Yes even when its out of band and your using the speaker off axis you must notch the on axis breakup node out of existance. This will get rid of the resonance harmonic distortion that the cone brings to the music. This is the key to making audax carbonfibre cones or seas metal cones sounding smooth effortless and clean. This might work for you

not sure if this helps in any way. Best idea is to try and get copies of voice coil magazine. These are very interesting + informative reads.

Tweeter- 2.2khz, -24bd slope
Midrange- 200-2.2khz, -24db slope
Midbass- 63-200hz, -24db slope
Sub- 71hz, -24db slope

Jas I've heard Simons car and he isnt the only one to let those xt25's play super low like that. It sounds 'ok' and works. I'm sure Simon and the others letting these tweeters play this low have experimented for countless hour to come up with thier xo points.

For competition...

Tweeter - 2.2khz

Mid - HP 56hz 24dB, LP 1.8khz

Sub - LP 50hz 18dB

For my speakers (Lotus reference), someone in elite car audio forum actually uses midbass LPF 800Hz @ 6db and tweeter HPF 3Khz @ 18db, unbelivable gap. Lotus mid has a spike at 4.5Khz, 2nd harmonic distortion at 2.5Khz and 3rd harmonic distortion at 1.5Khz.

Komodo i still believe in sacrificing linearity for better distortion figures. Tweeters and the upper mids is where you can really notice distortion. Allow the mids to play higher than you want, eq them + notch filter them and they will be better than a tweeter playing too low. I just think that designers sometimes get sucked into using too low a x-over point. 1.5khz is a little low for a standard 25-28mm tweeter no matter what the free air resonance maybe. The focal TD5 is flat right down to 1khz and its Fs is below 800hz and it is not recommended to be used with x-overs below 2khz. If i can find the article maybe we can post it up here somewhere (whats the legal ramifications of posting a printed article). why mention a tweeter thats not the xt. Well for a start i dont have an article by Voice Coil magazine about the xt25. Also the focal td5 is the flattest tweeter ive seen down to 1khz.

i think it was june 2003 voice coil issue...so i was wrong it wasnt the tlr but the td5 (the tlr replacement).

Interesting to see that all of you are running such steep crossover slopes. FWIW home audio speakers typically cross over at 6db/octave.

jas, I have moved the tweeters up to 2, 2.5 and 3kHz - all sound the same to me, perhaps when I try some other things I'll hear the difference.

Atm: Running subs upto 40 hz
Midbass 30-200
Ambients 10 khz up...
Oh and missing half a dozen speakers

Generally for comps, with 2 way I used to play supremos down to 1khz 24db for point sourcing with tweet

3 way - ambients 15 khz up, supremos around 5khz 6 db/oct, legatias 200hz up, elate 9's, 200hz down. (point sourcing with midrange)

But it's constantly changing. depending how loud Im playing, in comps you can really push your gear to the limits, as judges will always listen at low volumes.

Is this primarily to acheive phase linearity?

I thought it was to couple with the drivers natural roll-off to give a steeper slope. ie. a 6dB slope with a drivers natural xdB rolloff would produce an acoustic 24dB slope????

I was going to mention 6db/oct slopes, but was beaten.

By the way, just out of interest why 6db...is it possible to have say, a 1db/oct slope?

On that note: I believe that if you cross an entire octave after or prior to (depending on HP or LP) the natural rolloff of a driver then the natural roll-off does not come into effect at all, and only the electrical XO effect is heard.

simon try and get a copy of a back issue of voice coil magazine.

http://www.audioxpress.com/magsdirx/voxcoil/vcdrivdata.pdf

feb 2001 i think is the issue

so you tried 2-3khz and not much difference, just thought it might sound a little cleaner a little more effortless at higher volumes. I know the scanspeak dome revelator (the one with the massive phase plate) sounds spitty and a little edgy and harsh when used too low. Finally settled for a 12db/oct 3.5khz x-over for that tweeter dispite the fact that the mid struggles that high (18w8535)

The higher slopes often used in car audio help to limit the 'crosstalk' between widely separated drivers, and the associated smearing of the image.

Think I'll try 48dB slope and see where that goes

jas, I'm only running a 75W amp, so no need for 'high' volumes.

With slopes and such,



I try to keep away from severe slopes for tweeters/mids ect.

but when it comes to subwoofers and LP on midbass I like to have a fairly strong Slope like 18-30db

to help stop the crosstalk like above.



however on higher freqs I find I run into some pretty nasty combos running heavy slopes.



for some of you guys running like 1-2khz at 24db and such, try running 3-4khz at 12db, you will probably find this is so much smoother and nicer to listen too.



Juls

... which means that people with the tweets and mid drivers placed close together (like in the kickpanel) should be running shallower slopes?

I really have no idea why home audio speakers run such shallow slopes. I have resisted doing so in my car because I am afraid of blowing up my speakers.

if the drivers are (nearly) coincident, and sonically similar, then there's no reason to use high slopes (with their problems).

The reason to avoid 6dB slopes on a tweeter/mid is that excursion of the speaker is not reduced with decreasing frequency, so you effectively limit the power handling of the speaker. 12dB slope gives you 1/2 amount excursion per octave away from the XO freq.

most good home speakers I have heard use 12dB slopes.

as for slopes - I find running 12dB/oct on the tweeter messes with the midrange too much, so moving it up the scale leaves a hole.

Butterworth filters sound nicer than L-R, but are less accurate and harder to phase match.