I used to think like that also, until Dr. Geddes convinced me that one could successfully eq a low frequency response with little consequence
Lets focus on the measurements since thats all that matters in the end....That and our ears...Do you see something bad about the measurements? When I attempted to sum the sub/mid the first go round in vituixcad the resulting FR was plus minus 2db. Is this disappointing??
Having to use gain to bring the levels up could be an issue for noise floor and dynamic headroom. Yet its not an issue for my setup because I've been affected by neither.
Not using the 18H+ in your sub is a loss, if you ask me...but I am likely buyer biased lol. Wonna compare measurements? Actually what do good sub measurements look like? All the same? I say that because the way we use woofers around these parts, a lot of options could be used, to achieve similar results. I do like the idea of versatility...but to be honest. I desire the traits of the 18H+ and the challenges it presented, to adjust its FR to a sub friendly response, in my system design approach, has been minimal.
Lets focus on the measurements since thats all that matters in the end....That and our ears...Do you see something bad about the measurements? When I attempted to sum the sub/mid the first go round in vituixcad the resulting FR was plus minus 2db. Is this disappointing??
Having to use gain to bring the levels up could be an issue for noise floor and dynamic headroom. Yet its not an issue for my setup because I've been affected by neither.
Not using the 18H+ in your sub is a loss, if you ask me...but I am likely buyer biased lol. Wonna compare measurements? Actually what do good sub measurements look like? All the same? I say that because the way we use woofers around these parts, a lot of options could be used, to achieve similar results. I do like the idea of versatility...but to be honest. I desire the traits of the 18H+ and the challenges it presented, to adjust its FR to a sub friendly response, in my system design approach, has been minimal.
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2nd order lowpass doesn't seem much different to a linkwitz transform on this sub ? I've used low LP filters to tame a rising response and then a 2nd, higher frequency LP to perform the XO in quite a few car installs. (Combination of in-built amplifier xo's and head unit xo)
Have read on diyAudio plenty of times, doesn't matter what the electrical filters are, it's the acoustic result that matters.
Have read on diyAudio plenty of times, doesn't matter what the electrical filters are, it's the acoustic result that matters.
Yes, but! I find the whole idea of showing the SPL of a device in situations that ignore the room rather absurd. Yes, you can EQ to your hearts content at LFs (given enough capability) but then that also means that the source specs - minus the room - have no meaning since you will EQ in-situ in the end anyways. To me, his whole idea of looking at LF sources as free radiating devices, not in-situ ones, is kind of pointless.
I thought the point was to design in half space first. That remark seems more to do with dynamics right? Well the issue of a 2nd order xo at 21hz is also an issue of dynamics because make up gain will limit headroom and raise noise floor. In my case, it has not been a problem, proven by ability to achieve half space dynamic goals and the lack of hiss coming out of the driver in question complimented by low amp temps and no need for a high pass, per say.
That would be my point of looking at this in any other view outside of "in-situ".
One thought I had was that if I created a design with a fairly neutral response, and a ridiculous amount of headroom, that in the end, I would be able to sculpt various FR with no extra consequence. Seems to be working.
That would be my point of looking at this in any other view outside of "in-situ".
One thought I had was that if I created a design with a fairly neutral response, and a ridiculous amount of headroom, that in the end, I would be able to sculpt various FR with no extra consequence. Seems to be working.
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Yes, sir, even after the 24 db of make up gain, the bass from just one sub, is too loud and with volume up and no signal I hear no hiss with my ear up to slot...with plenty of gain leftover. Theres at least 5 gain stages, not including a separate adjustment for input sensitivity...
Give me a little time I'll put together pictures of the configuration...
Amps physical input gain knobs at 0
DSP input sensitivity is set to 32db but I can change it to 36db
DSP input gain is -10 (0 max)
Compressor gain is at 0, can be set to 20db
Eq gain is 0 (12db max)
Output gain is -10 (0 max)
Crossover is at 24db, and maxed out. sits in between input and eq
windows volume maxed, used youtube volume as master. Maxing this volume, rendered plenty loud enough, only really doing spurts of it....because it was ridiculous. 500v at 16ohms is what I captured....approximately 630 watts.
The amp is rated 625 at 16ohms...just enough rms to be too loud.
I was just reminded, my heat is lower because amps run cooler in higher ohms....If I can find a some way to manage the fan noise, these amps might be keepers.
Give me a little time I'll put together pictures of the configuration...
Amps physical input gain knobs at 0
DSP input sensitivity is set to 32db but I can change it to 36db
DSP input gain is -10 (0 max)
Compressor gain is at 0, can be set to 20db
Eq gain is 0 (12db max)
Output gain is -10 (0 max)
Crossover is at 24db, and maxed out. sits in between input and eq
windows volume maxed, used youtube volume as master. Maxing this volume, rendered plenty loud enough, only really doing spurts of it....because it was ridiculous. 500v at 16ohms is what I captured....approximately 630 watts.
The amp is rated 625 at 16ohms...just enough rms to be too loud.
I was just reminded, my heat is lower because amps run cooler in higher ohms....If I can find a some way to manage the fan noise, these amps might be keepers.
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There is no hiss because you are listening to a subwoofer with an acoustic and electronic low pass filter.
24dB of boost on a subwoofer that is not a dipole is suggestive of incorrect gain staging. But in reality you might well just be making up what you took somewhere else. From your measurements and Vituix sims I haven't the slightest idea what you are actually getting to make any kind of informed comment about.
Generally the CD on a horn will be be more sensitive than the rest of the system and need padding down, occasionally the lower drivers might get a bit of boost to level everything out. The hiss will come from the CD as it will amplify every last little bit of noise in the system and listening up close magnifies it.
Adding that amount of voltage gain should not be necessary is the point most are trying to make.
24dB of boost on a subwoofer that is not a dipole is suggestive of incorrect gain staging. But in reality you might well just be making up what you took somewhere else. From your measurements and Vituix sims I haven't the slightest idea what you are actually getting to make any kind of informed comment about.
Generally the CD on a horn will be be more sensitive than the rest of the system and need padding down, occasionally the lower drivers might get a bit of boost to level everything out. The hiss will come from the CD as it will amplify every last little bit of noise in the system and listening up close magnifies it.
Adding that amount of voltage gain should not be necessary is the point most are trying to make.
I was referring to the available headroom and the topic of s/n. The low order low pass pushes the sensitivity down...I used make up gain to return volume to normal as opposed to input. This method will lower headroom, and raise the signal to noise ratio. Not a problem for me that I can find as of yet.
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Pretty Much.
Should not be necessary unless....I use a low order cross over....as low as I am.....Did you not see Allens post above....its not unheard of...or "wrong"
Is there measurements taken in a certain way, that youd like to see? Im a ways off from being in the space were the speakers are to go....hanging out in the living room for a moment longer.
The low order crossover and makeup gain don't go together they are separate things even though you have used them together. There is nothing wrong with using a low order crossover low to blend two sources together over a wider bandwidth. It is the significant make up gain that seems odd to me not the crossover slope. Do you have a plan for the type of response you are aiming for and how you want the drivers to blend?
Yes! Its displayed in the Vituixcad picture, of course this idea will look different once the room is factored in.
The reason why I pointed to Allens post, other than his own legitimacy lol, did you note how low the sensitivity was as a result of the filters...make up gain is required.
I've been slowly applying filters, according to the vituixcad FR design, and then making observations after each change....I didnt get past the low pass and gain staging up....but it seems that a low pass and room eq is all this response needs in the sub region...There is very little need for voice eq with the cross band
The reason why I pointed to Allens post, other than his own legitimacy lol, did you note how low the sensitivity was as a result of the filters...make up gain is required.
I've been slowly applying filters, according to the vituixcad FR design, and then making observations after each change....I didnt get past the low pass and gain staging up....but it seems that a low pass and room eq is all this response needs in the sub region...There is very little need for voice eq with the cross band
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I have often done things like this, but to play and see what happens. It's active study into how things work.
Real solutions require a reasonableness test. Just because something can be done, doesn't make it a good solution.
That's not what I wrote. Comprehension should be a part of reading. At least get the words right. Not so easy huh?
A second order filter does not change the sensitivity or make it low. Two matched second order slopes would give you a flat response and a wide overlap normally with a polarity flip on one side.
There is something fundamentally wrong somewhere in your simulation. In the picture attached below you can see that the polar below zero is white. There is some kind of offset here and I think your gain is related to it. There should not be a 24dB difference in output between the PPSL sub and the mid driver. With two 18's matching to a 15 there should be more output on the sub.
Take a measurement of the sub raw without any processing and a measurement of the mid at the same distance with the same mic gain and see what the difference in sensitivity is between them.
I would look at what is causing the dips in the sub and mid circled in the attachment. It will be difficult to blend these together, it is not easy to tell when other EQ.
I am trying to be helpful instead of rude, there is a fundamental problem in the simulation that needs to be addressed to move forward.
