OT: High Pass end results
Dra
Posts: 3,777
Here is a good one.
A recent question by a poster and a Typical Gadget answer spawned a question.
Speaker spec given:
-3db point - 70hz
-10db point - 60hz
Is the natural slope of the drop-off considered an acoustic filter? If so (or not), does applying an electrical filter, BW18 at ?hz, affect the speaker's actual response as it applies to the actual amount of cut?
That is probably confusing. :shock:
Say one speaker is -3 & -10 @ 70hz & 60hz, and another speaker is 50hz & 40 hz... if a filter is applied that electrically matches the the slope of the speaker with the higher cut-off... will both speaker have the response, or will the the higher cut-off speaker have a deeper actual cut because the filters are "stacked"?
DRA
A recent question by a poster and a Typical Gadget answer spawned a question.
Speaker spec given:
-3db point - 70hz
-10db point - 60hz
Is the natural slope of the drop-off considered an acoustic filter? If so (or not), does applying an electrical filter, BW18 at ?hz, affect the speaker's actual response as it applies to the actual amount of cut?
That is probably confusing. :shock:
Say one speaker is -3 & -10 @ 70hz & 60hz, and another speaker is 50hz & 40 hz... if a filter is applied that electrically matches the the slope of the speaker with the higher cut-off... will both speaker have the response, or will the the higher cut-off speaker have a deeper actual cut because the filters are "stacked"?
DRA
0
Comments
Going from -3 down at 70Hz to -10 down at 60Hz is pretty steep......well -- after the 60Hz mark it will be. If the high pass is set high enough -- the slope will preserve the roll off a certain way meaning the curve will be a more gradual roll off.
I have no idea if this helps or if it is really what you are looking for. The natural roll off in what I have seen (using smaart) is probably a steeper roll off than using a BW18 filter. The problem is channeling all that power into a speaker at its natural acoustic limit. Not sure and maybe the sub could take it but for the specs above -- I would start the high pass at the -10dB down mark BW18 and just listen to see how the kick and bass sound. If it sounds muddy or sloppy and I couldn't get much of what I was looking for out of it -- I would start raising it slowly until the kick cleared up. Just throwing out ideas..... where is Dennis? He will know.
Let me see if I can find a snap shot of my subs and post them for you to see.
This thread started as a sub related question, but actually would make more sense as a high pass to the "woofer" speaker of the top cab as is interacts with the sub at the x-over region. Then, I guess, the example would make sense if the top cab has a 10" woofer (-3 @ 100hz) and a sub with an upper limit of 120hz.
Let me ask the question like this, "Does a natural limitation have the same characteristics as an applied filter? And therefore, does a "natural limitation" with a matching (assuming possible) "applied filter" yield the same results as an "applied filter" on top of a matching "applied filter"?
DRA
Now, if you overlay the slopes and actually apply the filter to the speaker.. the speaker response would follow the filter(as long as it is above the filter slope), and not the speakers.. however.. the electrical and acoustical slopes are going to differ... If the filter is applied and that filter slope is ABOVE the actual response of the speaker... then the speakers response will remain unchanged.. even though the filter is in place.
As confusing as the thread is I may be totally NOT answering the question though...
G
I don't think so Dra. Those specs sheets that companies put out always have the response EQ'd and tailored to make them look great BUT really by the time the buyer gets them & depending IF he has ALL the parts (system controller & amps...etc) then the natural response is often pretty ugly. So as the response rolls off -- it can be lumpy and jagged. When you get a filter into the mix and the filter cuts into the response -- it doesn't change that lumpiness or jaggedness -- it just rolls it off differently. It may be possible but I think it would be highly unlikely an electrical filter could lay right over an acoustic filter exactly.
However -- if you wanted to be slick -- you could EQ the response and force it to work that way but obviously that wouldn't be what you want to do. It is important to EQ thru the crossover area and beyond the XO points before joining the area together with a filter. This is something I was missing for awhile and honestly wasn't ready for it BUT it made a nice improvement in my system.
One other thing kinda off base but my top to electronic sub XO point is down around 70-74Hz BUT because my low end is strong (+10dB -+12dB minimum) it takes this lower setting to achieve an ACOUSTIC XO point of 118Hz. It shifts upstream that much! The electronic crossover will only closely match the acoustic XO IF the two are equal in volume (Flat).
Sorry. Thought I was clear and may additional clarification that I was discussing "real", but "made up" numbers.
I am working on something to post that may explain my thouights, though you actually touched on it in your reply.
DRA
Does this make sense? Again, I made the responses up and the filters, and the effect thereof. As a matter of theory... is this feasable?
DRA
I see what you are saying but a speakers natural response will never look like you have it. It is too gradual. It makes more sense to me to see the first two actually reversed. The natural will drop sharply at some point and the filter will actually preserve the response IF you get further into the response.
So if the filter is in place and not yet into the Natural range -- it will still look natural. As you creep into the response with the High pass -- it will take on a different look and the further you go into it -- will still keep changing until the HP Filter or the BW18 is in FULL control. Basically it will be 1. ALL Natural 2. Somewhere in between 3. BW Filter takes full control. I don't think in your example that the first one plus the second will equal the third one although it would be easy to conclude IF the first and the second actually looked like that.
The natural is going to have a rapid fall off at some point (-10dB @ ?) -- the Filter will have a BW 18 for example -- just THAT -- IF you get far enough into the response........ otherwise you will be in the middle of the two and get a half and half response.
Dra do you have any measuring capabilities and a program like Smaart? Although complicated at first -- it really teaches you an immense amount of things of what is happening in the acoustic realm. It is just different and amazing. I would be happy to help you with what I know. I am a solid two years into it now. I know Gary is getting into it and of course Dennis is the master at this (15-20 years I think) so he could clarify things as well.
It is cool to see you expanding the thought process..
Yep -- that's my answer. Anyone else have any ideas???
DRA
Take a look: http://i213.photobucket.com/albums/cc21 ... Slopes.jpg
Dra -- just went back and RE-read the original question. So you got a speaker that has a cut off higher than the other one and you want to use a filter on the lower one to match the higher one. Sure -- I think you can do it as long as you can use a measurement device to do it. Have to have a way to figure out the Filters Slope. From there join them together and align it. Sorry
Yeah, but the natural response of your speaker will look nothing like your pictures.
What do you suppose the anomaly is at 63hz on the 100 & 150hz traces?
DRA
Let me rephrase the question. If worm holes exist, and I fly a craft into it, does my speed change while inside, or does it speed up? If the speed is increased, is it instantanious or gradual?
My dad taught me this... "Words do not convey meaning." In other words... What I want to say = A. How I say it = B. What you hear = C. How you interpret it = D. :idea:
This whole exercise was fodder to begin with. Just something to discuss. Like the Butterfly Effect.
Concider it closed, unless there is any more real contribution.
DRA
With our lack of knowledge on the topic, could it not be dangerous to fly into a worm hole?
I don't know what else to say Dra. The anomalies on traces...... not sure but I hope you got the idea at least on the single speaker part. With careful filter use and possibly some EQ-ing -- you can make it match a natural response or even another filter.
I know you can combine speakers together with different slopes or filters. I have a setting I did a while back where I combined an LR24 (Mid) to an LR12 (Horn). The reason I did it was because of the phase position. A lot of speakers don't land on the same Phase line and are rotated out by 90 degrees or whatever. Using the LR12 on the horn re-positioned the phase to be right in line with the mid speakers phase. I ended up with a completely flat frequency response AND phase Response which is HIGHLY desired in sound BUT like Dennis told me -- It may look better BUT may not sound better.
Although it sounded pretty good -- it just wasn't the same as the other.
So you gonna give up on the question? Are we talking about two different speakers where one has a natural roll off and the other is high passed with a filter trying to match the natural one?
:? There are no speakers. They were a figment of my imagination. In fact this thread does not exist. In fact it is 1988. We are all part of a dream that Jerry Garcia is having because he ate a giant chocolate borrito.
DRA
But IF there were speakers, would they be different or matching?
Matching. in fact they are identical twin brothers. A dual 15 + 2" horn speaker, in the family way, bore down and popped these out of its port. She was so proud. They each weighed in at 46 lbs with lustrous black fur. Then... there it was... a cute little 1" horn, and for doing its business, a 12" cone. As the birthing engineer inserted a speakon and gave it a twist, they gave a squeal, took a deep breath, then.... aaaahhhhh... music.
DRA