My point was not to dismiss your points...rather, most of us here now understand what you are seeming to start to explain in more detail... so you are preaching to choir sort of speak. I in particular have weighed the pros n cons enough and still intend to use dsp to its potential...as well and to your liking, my design is to the full potential of ability to minimum phase and low(ish) order xo in order to have the best time domain performance with having to introduce signal delay of FIR, if chosen.
Well, either you just build something that sounds, put a mic in the listening position and EQ the s**t out of it to get the desired FR at listening position.
Or, you build a theoretically as perfect LF system as possible and then compensate for any room problems. Your call of course...
//
Or, you build a theoretically as perfect LF system as possible and then compensate for any room problems. Your call of course...
//
Hi,
A loooong but quite informative thread
I run a 2-way that is pretty much full range. When i moved into the house i was set on making a full 4-way, dsp assisted system and started with the 2-way that i envisioned as the heart of it. For bass duties in that 2-way i use my trusted GPA 416 in a 280l BR cabinet tuned to 30Hz after some port flow restriction. Above that i run a TD-4001 in a E-JMLC 300 horn. I used these horns at my previous place and there they where placed very far from any side wall and worked fine. In the current house they where not happy at all as they had to end up a lot closer to reflecting side walls. I tried many different ways of fixing this, both with EQ, crossover, room treatment etc and it was not until i jammed them into the corners that they started to sound balanced.
They do cover the spectrum from 30 to at least 16k but do beam a little more than i would like over about 8k. All i have to do now is to build some new corner cabinets.
//Anders
A loooong but quite informative thread
I run a 2-way that is pretty much full range. When i moved into the house i was set on making a full 4-way, dsp assisted system and started with the 2-way that i envisioned as the heart of it. For bass duties in that 2-way i use my trusted GPA 416 in a 280l BR cabinet tuned to 30Hz after some port flow restriction. Above that i run a TD-4001 in a E-JMLC 300 horn. I used these horns at my previous place and there they where placed very far from any side wall and worked fine. In the current house they where not happy at all as they had to end up a lot closer to reflecting side walls. I tried many different ways of fixing this, both with EQ, crossover, room treatment etc and it was not until i jammed them into the corners that they started to sound balanced.
They do cover the spectrum from 30 to at least 16k but do beam a little more than i would like over about 8k. All i have to do now is to build some new corner cabinets.
//Anders
Measure twice, cut once buddy lol
Welt I've only experienced a single 15m in my living room upstairs and random stuff with a single compression driver and horn downstairs....
The 15m was attached to a 90watt (8 ohm) receiver, so I am not certain how many watts its getting at 16ohm, but I already knew that these drivers are sensitive so it should make some type of noise. With just one 15m playing fullrange it was reaching impressive in my mind. My daughter thought that it was as loud as my stereo in the basement with 1+4+12's per side... and she was more surprised when I told her it was just one 15" playing, and that 5 more drivers not including the horns, needed to be added....I had to further explain the connection between loudness potential and SQ so she could see why the system was so powerful....Personally I thought there would be a tad bit more bass ooophm (from the one 15") but consider....it is a 15m geared towards high resolution of midrange and in a sealed enclosure without any eqing of the roll off, on a not so powerful amp....with a medium xmax.
So basically I think I am hitting my target....Its hard to conceptualized a diaphragm being able to make the excursion I was seeing without completely destroying the mid/hf it was playing.....Only at max volume on the amp and the lowest notes of the Rap song I demo'd did I start to hear trouble in the midrange....but I think it was the amp not the driver having issue....and if it was the driver, it was likely THD being transferred from the the bass excursions.
From there my thoughts went to....OK I can see how the Strauss proves the point of this thread.....Its woofer is likely more bass capable, in particular in a vented cab.....The M2 woofer, as well, in a vented cab. I know more of the JBL 2216nd being a hybrid of sorts, concerning qualities of a bass vs a midrange, basically meeting in the middle.
With a top shelf HF solution on top of these top shelf woofers....looking at music, I think the horn(waveguide)+15" can't be beat. Though I've never heard the 18H+ in this scenario...John does hold it in high regard...over the 15" Tad in the Strauss to be specific.
Full range was always a matter of speculation in this thread....I specified 30hz....With a vented design and room gain to boot, I don't think anyone is going to have any complaints unless in the genres that really ask for the lowest of notes....the nail in the coffin for the 2 way approach would be TMM and MTM along with the vented aspect to support the low end. 2 ways with subs in the room.....without a doubt.
High SPl was a matter of speculation in this thread, to which I stated 115db at one meter. I'd have to do some more demoing with the spl meter out to see what was what. I can tell you by my simulation experience, you aren't going to get 115 in the bass department, low distortion...without enough xmax/Sd...you must consider that even though bass and distortion is somewhat forgiving...once the woofer gets into higher excursion via bass production...those THD issues do transfer to the rest of the spectrum under preproduction at the time, something I verified with Dr. Geddes. So in regards to that....playing music with low bass (Rap Edm for example) and having peaks at 115db, which is going to be the level the bass will reach while the rest of the range is lower in spl as you move up range (see pink noise and equal loudness contour)....These more extreme sources of bass are going to introduce distortion (even if its just "medium") at high listening volumes. If its not THD due to excursion, it will be group delay due to vent tuning being place within passband. Just like THD from bass bleeds into the mid, I suspect, Group Delay to have a similar effect while the woofer is playing the notes within with the high pressure areas of the bandwidth. I think this situation will still be good enough for a lot of people and only people with highest expectations and listening to these genres are going to care.
115db is not exactly a random number, it just a reference spl at 1 meter, I knew of, and used to decide if the system is going to be able to handle transient peaks in an uninhibited fashion during lower levels of RMS playback.
Here
The importance of Kms(X) and BL(x) for mid-ranges
is an interesting discussion of theory and towards the tail end of the "meat" you'll see a common denominator of Low excursion being the epitome of SQ. Nothing new but, it is King. Vented designs do help lower excursion and make this 2 way goal a reality. All of this being a focus on music....The expectations people exhibit if you mention the words "sub bass" tells me that they are serious about getting below 30hz regardless if "upper sub bass" has been handled....Without getting into that, my point is low distortion of even 30hz is going require.....low excursion....I just pointed out above that THD will permeate all the sound being produced even if the excursion causing it is not seemingly suffering....Get it?
You can produce acceptable bass at higher thd levels it seems....but as soon as you let that driver incorporate midrange into its output, the excursion from the bass is going to be a problem. This is whats going to make or break your goal of reaching the full range 2 way dreams....from here you have driver SD, Xmax, TMM/MTM, vented cab, and complimentary subwoofers, as tools to thread the needle of success...and allow me to say Yes to the titled question.
The best advice I've received in this thread was from....(?)....who told me to not allow any driver handling mid range exceed 2mm ....and Gedlee who said, see it move, see it distort. Combine that with the necessity of a double bass array, more/less, the multi sub approach, to achieve linear FR response.....if we null that out of the equation since its true for everyone usually...then again a large 2 way is going to be choice, to sit on top of the status quo sub bass system for SQ.
Welt I've only experienced a single 15m in my living room upstairs and random stuff with a single compression driver and horn downstairs....
The 15m was attached to a 90watt (8 ohm) receiver, so I am not certain how many watts its getting at 16ohm, but I already knew that these drivers are sensitive so it should make some type of noise. With just one 15m playing fullrange it was reaching impressive in my mind. My daughter thought that it was as loud as my stereo in the basement with 1+4+12's per side... and she was more surprised when I told her it was just one 15" playing, and that 5 more drivers not including the horns, needed to be added....I had to further explain the connection between loudness potential and SQ so she could see why the system was so powerful....Personally I thought there would be a tad bit more bass ooophm (from the one 15") but consider....it is a 15m geared towards high resolution of midrange and in a sealed enclosure without any eqing of the roll off, on a not so powerful amp....with a medium xmax.
So basically I think I am hitting my target....Its hard to conceptualized a diaphragm being able to make the excursion I was seeing without completely destroying the mid/hf it was playing.....Only at max volume on the amp and the lowest notes of the Rap song I demo'd did I start to hear trouble in the midrange....but I think it was the amp not the driver having issue....and if it was the driver, it was likely THD being transferred from the the bass excursions.
From there my thoughts went to....OK I can see how the Strauss proves the point of this thread.....Its woofer is likely more bass capable, in particular in a vented cab.....The M2 woofer, as well, in a vented cab. I know more of the JBL 2216nd being a hybrid of sorts, concerning qualities of a bass vs a midrange, basically meeting in the middle.
With a top shelf HF solution on top of these top shelf woofers....looking at music, I think the horn(waveguide)+15" can't be beat. Though I've never heard the 18H+ in this scenario...John does hold it in high regard...over the 15" Tad in the Strauss to be specific.
Full range was always a matter of speculation in this thread....I specified 30hz....With a vented design and room gain to boot, I don't think anyone is going to have any complaints unless in the genres that really ask for the lowest of notes....the nail in the coffin for the 2 way approach would be TMM and MTM along with the vented aspect to support the low end. 2 ways with subs in the room.....without a doubt.
High SPl was a matter of speculation in this thread, to which I stated 115db at one meter. I'd have to do some more demoing with the spl meter out to see what was what. I can tell you by my simulation experience, you aren't going to get 115 in the bass department, low distortion...without enough xmax/Sd...you must consider that even though bass and distortion is somewhat forgiving...once the woofer gets into higher excursion via bass production...those THD issues do transfer to the rest of the spectrum under preproduction at the time, something I verified with Dr. Geddes. So in regards to that....playing music with low bass (Rap Edm for example) and having peaks at 115db, which is going to be the level the bass will reach while the rest of the range is lower in spl as you move up range (see pink noise and equal loudness contour)....These more extreme sources of bass are going to introduce distortion (even if its just "medium") at high listening volumes. If its not THD due to excursion, it will be group delay due to vent tuning being place within passband. Just like THD from bass bleeds into the mid, I suspect, Group Delay to have a similar effect while the woofer is playing the notes within with the high pressure areas of the bandwidth. I think this situation will still be good enough for a lot of people and only people with highest expectations and listening to these genres are going to care.
115db is not exactly a random number, it just a reference spl at 1 meter, I knew of, and used to decide if the system is going to be able to handle transient peaks in an uninhibited fashion during lower levels of RMS playback.
Here
The importance of Kms(X) and BL(x) for mid-ranges
is an interesting discussion of theory and towards the tail end of the "meat" you'll see a common denominator of Low excursion being the epitome of SQ. Nothing new but, it is King. Vented designs do help lower excursion and make this 2 way goal a reality. All of this being a focus on music....The expectations people exhibit if you mention the words "sub bass" tells me that they are serious about getting below 30hz regardless if "upper sub bass" has been handled....Without getting into that, my point is low distortion of even 30hz is going require.....low excursion....I just pointed out above that THD will permeate all the sound being produced even if the excursion causing it is not seemingly suffering....Get it?
You can produce acceptable bass at higher thd levels it seems....but as soon as you let that driver incorporate midrange into its output, the excursion from the bass is going to be a problem. This is whats going to make or break your goal of reaching the full range 2 way dreams....from here you have driver SD, Xmax, TMM/MTM, vented cab, and complimentary subwoofers, as tools to thread the needle of success...and allow me to say Yes to the titled question.
The best advice I've received in this thread was from....(?)....who told me to not allow any driver handling mid range exceed 2mm ....and Gedlee who said, see it move, see it distort. Combine that with the necessity of a double bass array, more/less, the multi sub approach, to achieve linear FR response.....if we null that out of the equation since its true for everyone usually...then again a large 2 way is going to be choice, to sit on top of the status quo sub bass system for SQ.
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I tried to do reverse order of operations to get BL out of my measured specs and the number that I am getting isn't making sense to me...
Something I am doing wrong or not understanding of course..
2pi
Fs=42hz
mms=66.484
Re=12.5
multiplied by
Qes= 0.766
BL should equal square root (Answer) to above.
Attachments
Well, if I am sitting where I "should" it is not a problem but the room is big with more than one place to sit and enjoy music and as it is I can't get the right tonal balance at various places. I do have two different settings in my DSP that I can shift between but I would rather not.
Something isn't right with the parameters as they don't calculate correctly.
This formula works for me if I check most manufactures spec sheets and enter the Mms value in Kg (multiply grams by 0.001)
Qes = 2 Pi x Fs x Mms / (Bl2/Re)
Example Faital 8RS250
6.28318530718 x 56 x 0.0306 = 10.76686634238365 / (182.25/5.7) = 0.33674
Rounded up to the 0.34 in the Datasheet
OK I am back with another trend....which supports the trend I found where BL was 75% of advertised.....I took a faital pro 10" woofer that had two different versions regarding ohmage....divided the 4ohm version by the 8ohm version...then I took that number multiplied it by the 4ohm version of the 18H+ and I was with 0.01 of the Qes I get for my 8ohm 18H+
So any reason why Qes would decrease as a result of break in?
Issue would be that all ohm versions same model woofer of AE show matching Qes.....is this normal for woofers?
And then for another pair of faital pro woofers qts says the same fir 8 vs 4 ohm versions....so I guess its a thing...
So any reason why Qes would decrease as a result of break in?
Issue would be that all ohm versions same model woofer of AE show matching Qes.....is this normal for woofers?
And then for another pair of faital pro woofers qts says the same fir 8 vs 4 ohm versions....so I guess its a thing...
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Based on the formula above if the Fs goes down so does the Qes so yes it would change as the driver loosens up.
Have a look at the 15FH500 as it is available in 4, 8 and 16 Ohms. Lots of parameters change with the impedance.
FaitalPRO | LF Loudspeakers | 15FH500 (4Ω)