I am currently running my BA pro's active off the headunit.

then put the x-overs back on today, and the sound is just amazing, about 10 times better than my active setup

I get a tonne more midbass, the tweeters integrate with the mids really well, the sub bass blends in better, and everything is just clearer!
but more so, huge midbass gains..

Its like the mids were out of phase! even though I have tried everything with them, changing speaker polarity etc, even bi amping them I dont seem to get the midbass snap Im after compared to passive setup

also have selected off-axis in the x-over settings for the woofer

Boston will not release the specs on there passive crossover... as I have emailed there support address. also other people cannot get this information off them
is there anyway apart from trial and error to get the same sound from the passives onto an active system?

Can people tell from looking at the x-over components or schematics etc?

and/or why this is happening?

the reason I want to go active is to give better control on each speaker, get time alignment working as well and to utilise my other 2 channels on the amp, as the alpine cannot all 4 channels bridged into 2!!

The trick is with active, you cannot easily get the volumes of each speaker input matched as easily as if you where running
the passive, the other issue is finding the right mixture of crossover points, there is many things that vary.

Running active isn't easy, it takes alot of time and effort sometimes

Often X/overs can have mild EQ in them as well, which can effect the way the speakers sound.

my suggestion to you is that when you where running the speakers actively, that the levels from the mid to tweeter,
and the crossover setting was wrong.

Phase is also a issue, often passive crossovers have phase correction also built in,
this is something you have to toy with running active, and alterations to x/over points can alter the
required phase..

but generally speaking the speakers should be wired up correctly, (check check and check again) and that should be all you need,
mostly only subwoofers tend to suffer from a need to be out of phase to be in phase. (depending on the install)

for more midbass snap, use a 24db cut on the midbass driver, tweeters can run a 12-24 db cut depending how low you go,

suggest a 3-4khz selection. you can also underlap or overlap as neccessary.

I often find 12db slopes are the easiest to deal with, but you don't get the snappy midbass as much.

even if you did get the x/over points from the manufacturer, just inputting them into your head unit or processor
may not (and is unlikely to) achieve the same result. if you have the gains too high or too low on the amp, (depsite being able to adjust at the processor)
then things still won't work right.

You have three main things you need to get right when running active,

1. Crossover point
2. Crossover Slope
3. Individual Speaker Volumes
and
4. Possibly separated time alignment settings (which will effect the sound you hear)

thing you need to realise is Boston spent alot of time and money making sure they got there
crossover exactly perfect for that speaker set, so to think some pleb with a bunch of buttons can do
better by just fiddling around is stretching things.

Yes you can get even better sound with active, but you need to know what your doing,
and be prepared to spend the time end effort getting it right. Most people
fail miserably. Generally cheap splits often benefit the most from going active.

Juls

Since Boston wont help, for this I can suggest you get a hold of an ociliscope OR an RTA, either with a microphone and use either a frequency sweep CD or a tone generator, generator is better.
Then 'look' for the roll off points. Do one speaker at a time, ie do the tweeters on their own (passively conneted), the mid, then the woofers etc... try and see were on the RTA/cro/scope dohte waves beggin to get the dips on the high range and the low. Then look at how steep/sudden the change is. These can be your reference points for when going back to active...
Hope that helps.

Setting up active is easy, just follow these steps.

1. Set mid high pass to 50-80Hz (what ever works for you car)
2. Set Mid low pass to 5k
3. Set Tweet high pass to 5k
4. Set mid gain
5. Set tweeter gain
6. Lower mid/tweet crossover by ear (within reason)
7. Tweak tweet gain

That said, passives work really well at high frequencies, the biggest gains from going active are to be had from sub bass to midbass and midbass to midrange.

Bi-amping is always an option if you're unsure about crossover point and phase. Any passive can be chopped to make bi-amping possible.

Phil

well ever since I have gotten the p80rs headunit, im forever adjusting the settings, x-over settings...

as one day I think it sounds right, then the next day I hear a different song and hate it

I dont like giving up on things, and I want to set it up active.

even bi-amping doesnt sound very good on my system

I dont have access to an RTA either

to be honest, its like my speakers were out of phase when running them active, the mids more so
I also tried the obvious, changing the speaker wire around, to reverse the polarity, still no go
Double checked all wiring and it is fine, had changed the slope, and x-over points and still couldnt get them right..
they are mounted off axis in my install, when I crossed them over at 2.5khz LP they started sounding very harsh (the mids) so then back to 2khz and they were fine, and this was trying the different combinations of 12, 18 and 24 db/oct

if I did them at 1.6khz LP I seemed to lose alot of detail.
the tweeters are mounted in my kicks on axis, which I think sounds great now im running the passives, but at 3.15khz LP they were too bright even at -24db/oct, crossed over at 4khz, they were a little nicer to listen too
then the next x-over point on the headunit is 6.3 khz, which sounded just right my tweeter at at alower slope tried 12 and 18 -db/oct

but the midbass was the main issue, when hp'ing the mids, they were always at 63hz on a -24db/oct slope and still stuff all midbass even tried full range lol and still not alot, so in my last car I put more DMX in the doors and sealed the doors up properly still no real gain, in my new car the doors are sealed with DMX in the outer panels, even boosting some of the lower mid bass frequencies didnt have much effect.
now when running the passive I have them at 80hz at -24db/oct and I get tonnes of mid bass of out the bostons

there was also a setting in the passive x-overs for off- axis and components
what does off axis setting technically do with the mid from the x-overs control?

Considering your experience Phil, that is one of the most worthless and over generalised posts I've seen. I was looking for the joke but I can't see it, am I missing something.

Ok from what you've posted I would suggest it isn't a lack of midbass but more so an excess of midrange which is causing harshness before the midbass gets a chance to get up and boogey lol. I would suggest you try eq'ing down some midrange freq, as it sounds like your issue isnt a lack of midbass but more likely an excess of midrange causing it to reach a higher level sooner and start to breakup sooner through the midrange making it sound harsh, causing the midbass to sound a little lacking in output since the midrange has hit it's limit before the midbass has, so if you cut some freq through the midrange it will allow for a much more linear sound and for the midbass to reach it's output limit around the same time as your midrange. You may find that the Boston Passive allows for this and has some sort of midrange cut through the passive, and which once you've taken the passive out of the loop has caused midrange brightness and the harshness.

My DLS mids are much the same they have a massive rise from about 160hz through to 400hz (where they cross) so I have to use a combination of cuts at 200, 250, 400 and 500 to tone down the lower midrange otherwise it becomes very bright and harsh, and then some eq boosts centred around 100hz.

No, it's that simple.

Tweeters require bugger all power compared to the mids. The mid gain will determine "overall" gains, with tweeters balanced relative to mids.

The crossover point is best set by ear.

Phil

Luke- Phil is pretty much dead on teh money. That is exactly how I ran my BA Pro's. Worked great.

Because my tweeters were in the pillars, I went for a higher xover point for them. Where as, if they were closer to the actual mid driver, it would have been a lower xover point.

Yes, it may have been a generalised post.. but still you can't argue, when its correct.

I know Eric from Image Dynamics USA.. suggests setting their speakers up like this.

I think Phills idea works quite well. Mid gain is much more critical to set correctly first, then tweeter gain should follow. Who sets their tweeter gain to max volume, then trys to match the mid to it. I doubt the mids could keep up, haha.

Crossover points and slopes however vary on every driver, location, and even prefered types of listening styles, which is why I think tuning by ear is a great idea.

thats exactly what I did with my mids though, I boosted the midbass frequencies from around 125hz upwards to about 500hz
as I found harshness around 800hz-2khz mark, which I then had to cut in order to stop alot of the harshness coming from the mid. still alot more midrange than midbass.

my gains are set to nearly minium on the amp for the tweeter channels

Yes I agree with the mid range being too loud, thats exactly it I think, so what other way can i cut the mid range frequency down and boost the mid bass on a 2 way system using crossover points? or can it only be done with an EQ?



I had my pro's in the pillars on my old car, and found they were too bright, and after mounting them in the kicks they sound awesome, whilst still keeping a good stage height

what were you mids crossed at? and the slope?

you can try to underlap the mid, tweet crossover, this should get rid of some of the midrange, just be carefull, as you may get rid of to much, or, it may be at the wrong spots.

Try some eq, A parametric EQ works well for this, set the frequency, and select a large Q (small number). I know in mycar this helped quite a bit, with me Eqin down 3.2k as my mids have a large peak around here.

I would think the Boston pasive has some form of EQ in it, or notch filter to smoothen out there response. Anything you can do with a stock passive, you can do with an active crossover aswell, it just may take some time, and alot of small tweeks.

Don't boost above 160hz anything past this and your countering your boost at 125, because IMO midbass is well and truly finished by 160 and your well on your way into lower midrange, I'd be cutting from 160 upto 500hz if it was me!!! The impact part of Midbass is actually a very narrow band of music much like subbass that's about 0-60hz, the Impact part of Midbass IMO only really lasts another 60 or 80 hz up from that.

I honestly can't remember, it was few years back. My tweeters fired into the windscreen, as on axis they did tend to "sizzle" abit to listen to. Aiming into the screen, helped defuse them a bit.

Now, I have ID horns, and another world of pain to setup them up

Ok I'll rephrase it, it was the 5k point you chose that caught my attention, but you changed that in the quoted post so all good then then i guess, the gain setting stuff I had no issue with.

Got me a bit by supprise to, but, Its a highish point to start from, but a good one as you can then work down, and trial different points. Easier than starting at say 3k, and having to try up, and down.

OMG, i actually agree with Phill for once. hahah.

does anyone know what the off-axis setting actually does on the x-over for these bostons?

As ar3nbe aluded to, it most likely adds or removes some sort filtering to freq's that are affected when a driver is positioned off axis, someone else can probably suggest what those freq ranges are most likely to be.

most passive crossovers are about 3 to 5 kHz.

the levels are very important.

better to use 6 or 18dB/oct rather than 12 or 24.

the "off-axis" is most like some phase correction.

also, passives usually have impedance correction, so the amp sees a more linear load to work better.

No it was right there in my original post, you even quoted me.



I suggested 5k as a starting point for safety reasons, given that the crossover point of the Bostons was un-determined.

Phil

thanks Phil I might give this a go today , and start again

Hey. Cool HU.

Have you tried switching the phase on one of the midbass speakers? you can do this with your HU quite easily by holding in the right hand button when you have the mid crossover selected, and has worked wonders for me (not sure why though...something to do with increasing the acoustic crosstalk).

ie, my left midbass is running 63-2.5kHz, and is set to "normal" phase
my right midbass is set to "reverse" phase

This has meant a slight loss of midbass for me, but has improved the stability of the image heaps. its entirely possible that it might do the opposite for you.

also, when trying this, try switching them (ie left is "rev", right is "nor" OR left=nor right=rev), as this can help as well.


Pulse-R, can you elaborate why one might use a 6% or 18% slope on tweeters? you did that on mine, and i ended up changing it back cause I wasnt totally satisfied, but i'd like to know the theory behind it...

What headunit do you have?
I can only change the phase on both at the same time?

because most Xover's aren't linear phase, and therefore, they produce a phase shift at the Xover point. The standard 6dB/oct = 90deg, 12dB/oct = 180deg, 18dB/oct = 270deg and 24dB/oct = 360deg is a rule of thumb that is fairly good in approximation. This holds true however, only at the point of acoustic disturbance (ie, at the cone itself).

This is the difference between an electric Xover and an acoustic Xover, for the acoustic may change depending on the acoustic space its playing in. You may find (and most of the time will) that the phase shift continues to change throughout the acoustic space. By choosing say a 6dB/oct (90deg) or 18dB/oct (270deg) you're introducing an abnormal phase shift, but allowing the acoustic space to continue this change so that it is a full 180 or 360 degrees out of phase by the time it reaches your ears.

From here, you can either fix normal or reverse polarity, to easily rectify the phase shift to normal. Clever, but a common tool. Does not work under all circumstances (biggest factor that influences is driver positioning).

I've got the same HU as you mate.

as I said above, hold the right hand knob depressed for a couple of seconds when you have the mid crossover function selected. it will then select the individual L or R channel. you can select the other channel by pressing the knob again. Now twist the knob to the the right to select the phase slope/phase shift function. you can now shift the phase 180% (either "nor" or "rev") for both L and R separately
this also works on the EQ, meaning you can set the L and R eq's separately.

cool huh?

hahah thanks man!

your a star!
I never knew that was possible on this headunit

Im running out of time today to run it active again, but im certainly going to give this a go again!

well changing the phase as mentioned above, has worked wonders for my midbass in active mode.

I think I might have done it now...

I started with the mids, one side has the passive x-over and the other side, was active
I found the active side best matched when I crossed it over at 4khz @ -18 db/oct ...

then disconnected the mids, and started on the tweeters
with one side being passive and the other active
I found the gain was too low on the active tweeter, once I got the gains right, I then set the tweeter volume on the headnit which then matched
then crossed if over at 3.15khz @ -24 db/oct which sounds pretty much smack on with the passive tweeter

when testing the passives, I noticed alot of detail off the bostons when only the tweeter connected then disconnected that and compared the mid, as if they are playing a much bigger frequency range, I guess being a 2 way component set it would have to

also going back to the off axis, as I think a few mentioned earlier, my bet is that its more to do with the phase on each woofer when off axis, which makes sense really

now everything is connected active and it sounds good! just a bit of eq'ing now to finish it off

I also left from 200hz and upper frequnecies as normal, and just boosted 125 and 80 hz to give me that midbass edge.

also my mids are now hp'ed at 80hz @ -24 db/oct

and the sub blends in nice at 50hz (idmax10)


i guess if I change my mind again! I will just use the passives again and sell the alpine f545 ... to replace with a 4 channel that can be bridged

I woludn't say it's that easy.

Every situation is different, and its very difficult to try to apply a 'one rule fits all' type concept.

did a bit more tweaking today, changed the mid LP to 3.15khz on the system, cant remeber what slope I used

sounds much better now, will now have to redo the gain on my sub amp..
and adjusted the phase on the right hand speakers


I think im pretty close now to the sound I was getting from the passives

you should be able to drop the hp on the mids down to 63 or 50 with no real problems, especially with a steep slope. not sure if it will affect the midbass "snap" you're after, but should help to blend with the sub

I always find most cars tend to suffer a midrange boost from 400hz through to around 800khz, then another boost often around 2.5khz (both to do with our ears and the cars accoustics)

which makes the midbass seem very weak.

some speakers sets suffer differently, but on average almost every car I listen too is overly loud in the 250-800hz range, and then again in the 1.6-4khz range, and sometimes in the 10khz range.

With your active crossovers in your headunit, it's important to realise the active crossover is nothing more than a electronic EQ. Very similar to the EQ thats also included in the processor.

so to a certain extent you can bend and manipulate the crossover points further by using the graphic or parametric EQ.

Everyone reaches straight for the high slopes, 24db and 18db, somehow thinking they are for some reason superior.. they are not.. more often than not blending between a 2 way set needs 12 or even 6db slopes.

some of DLS's top of the line speakers still use a 6 and 12db slope in there splits.
when you get into 3 way speakers each speaker has more capability to reach evenly into each of the other speakers range, so it's easier to get away with steeper slopes, you don't create as many dips.

Choose your crossovers to suit the available frequency response at the required power level for the speaker, and to moderatly match the required overall response.

from that point you can begin to EQ and Level set.

With your midbass drivers, I always reach for a 70 or 80hz 12db slope for my high pass, this flows
with the speakers own drop off in frequency response, While allowing the midbass driver to play deeply into the sub bass range, but stopping it from receiving so much movement that it is not capable of.

Most 6" midbass drivers can handle 12db @ 70 hz, I have noted a few that where not capable at moderate power levels, (boston Z6, Dyns and more I havn't tried yet). Often this crossover sounds alot better than say 63 @ 24, or even 50 @ 24 and blends nicer with the sub.

Almost always use a 24db cut on the subwoofer, between 60 and 80hz. depending on how strong your midbass is, you may opt for a 12db slope if you where running say 5" midbass drivers.

The most annoying thing is, very few processors offer a 56, 71 and 90hz crossover options,

leaving you only with 50, 63, 80 and 100..

Juls

VIP318:
The idea of the 'odd-order' crossovers is to minimise phase shift, i.e. there's only 90º Phase shift between the drivers, so it can sound better in some circumstances.
I find it gives a smoother sound as the speakers blend more. But then TA becomes more critical



p.s. to get the º symbol, hold down the 'alt' key and type '0186' on the keypad..

Wow... Interesting thread... I feel lucky that I had very little drama in setting up my HX-D2, three way active. The best thing I did was to listen to tracks I knew on chesky/sheffield CD's, and change the phase of each set of speakers till I found the setup that sounded the best, with the best imaging. I dont know if the P80 has it, but being able to mute certain drivers from the head unit without unplugging RCA's is also a great help - worth seeing if the P80 has that function

good luck!

Yes this is a good thread alright, I have learnt alot.
I might tweak my speakers x-over points.

Also the sound gets rather loud on my sound system around 800hz to 2khz, So Ive had to cut some of those frequencies just to smooth it out by ear
as my mids are off axis and the tweeters are on axis, was the same in 2 different cars

Dont knock hear tunning. Infact, get a signwave cd, and tune that "flat" to your ear. You will be supprised how good it will actually sound.

Remember, ear flat is nowhere near RTA Flat.

That said, For best sound, things should be done in the following order.
1. Speaker positioning
2. Crossovers + level control
3. Eq

If you're going to do it totally by ear, try using a tone disc. You can download tones from the net, that correspond to your EQ settings. Then play them, adjust for centre image, and level.

Actually does work quite well, without going to measuring equipment.

im not a pro or anything, but in not starting to wish I had more bands to play with on the eq and a better range of x-over points..

I'd prefer a 12 or 24 myself.

24dB presents a 360 degree phase shift (i.e. back where you started) so is kinda like no phase shift - seems preferable to me.

12dB presents a 180 degree phase shift which isn't perfect... however can be flipped easilly enough, as many head units have a 0/180 degrees switch.

6dB and 18dB on the other hand result in odd phase shifts which are more difficult to correct. I'd go with 24dB if i had it, but the Clarion doesn't - the only thing about it these days that I wish I had.



Optimally, it would boost frequencies above the roll-off point to counter for high frequency roll-off - however I'm not sure if this is the case or not.



Not exactly.

The amount of power needed is not determined by whether it's a mid or a tweeter, it's determined by the sensitivity (generally).

Tweeters often do need less power to keep up because they are usually more sensitive, however this is quite a generalisation and wouldnt necesarilly be true in every case.

For example, if your tweeters have an 88dB sensitivity, and your mids have a 91dB sensitivity, then your tweeters would actually need (in theory) roughly twice as much power as your mids, otherwise the system would be midrange heavy.

Crossover point can be set by ear, however I wouldn't say it's best set by ear necesarilly. Anything set by ear can be decieving - surrounding frequencies and gain levels and play games with your head sometimes when tuning by ear. I usually would refer to objective data (RTA readings, response graphs, distortion tests, etc) for setting crossover points first and foremost - then if it's not right (9/10 times it should be, if carefully installed) you can fine tune by ear.

Having built hundreds of cars over the past 15+ years, I can say with great certainty that tweeters always need less power than mids.

Phil

I have gone back to passives for now...
I just give up with the idea of going active with the boston pro's

Im thinking of selling the speakers and speaker amp later on

Please - spare me the "I'm right because I've been doing this for X years" bullcrap. If you know as much as you claim to, then you should't need to dig up your installation history in order to convince people of your credability.

To say tweeters always need less power then mids is not accurate. It's like saying sports cars are always lap a track faster then luxury cars. Sure it's true in most cases, but put an Audi RS6 up against a Hyundai Tubiron, and the results might argue otherwise.

In the vast majority of cases tweeters will be more sensitive then mids, and hence will need less power to reach the same volume level. It's because their sensitivity is higher, NOT simply because they are a tweeter. There are tweeters out there with 89dB sensitivity, and there are mids out there with a sensitivity of over 90 dB.

Find me a tweeter with 90dB (1w/1m) sensitivity, a sub with 90dB (1w/wm) sensitivity, and a midrange with 90dB (1w/1m) sensitivity and at the end of the day they will require roughly the same amount of power to reach the same volume level.

An amplifier doesnt say to a tweeter "I feel sorry for you because you are small, so I'll amplify more strongly for you!".

Perhaps in every active install you have done, the tweeter has needed less power - doesn't make it a law of physics. when it does become a law of physics then come back and tell me, and I'll believe you.

My XXLS sub has a sensitivity of 92.5dB, and my tweeters have a sensitivity of 92.5dB - given the same amoung of power, from the same distance, both wiould go equally loud.

As a perfect example, a Vifa XT19 Ring Radiator has a sensitivity of 89dB. My 7" Scanspeak Revelator mid also has a sensitivity of 89dB. To reach a certain output level, they would both need approximately the same input power.

In the other direction, if that XT19 happened to be say, 8ohm (as opposed to the Revelator, being 4ohm) then the Vifa tweeter would actually need approximately DOUBLE the power of the mid in order to reach the same output level.

So on average yes, tweeters are more sensitive then cone midranges, and thus need less power to get the same volume level... but this is an assumption based on a generalisation - it won't ALWAYS be true.

There is far more to it then just "tweeters are always louder".