One day I decided to plug my laptop into my receiver and fool around with the Scope program I downloaded. I was going to play around with the tone generator, and see what my Cerwin Vega D7's could do (or not do). I also wanted to play some low tones to help break in the re-coned woofers. The speakers seemed to hit reasonably low, but I decided not to play it loud with anything lower than 30 hz as I suspected the 12 inch woofers were not tuned lower than that. I set to 30 HZ and turned off my subwoofer. I turned up the volume slowly to find that at high volume, the woofers had a severe seal issue and air was farting out of the baffle where the woofer basket was bolted down. You could feel it with your hand and it was very loud and ruining the quality! 🙁 I knew I had to seal it. I also found that a big pot in the kitchen had a resonant frequency of exactly 80 hz 😀 The lid was going crazy! I fixed that 😛
So..... I go to Home Depot to look for foam strips to put on baffle. Nothing thin enough. I then realized I can use rope caulk. So I bought a roll for 5 bucks. When I took the woofers out to have them re-coned, I knew I was going to have to do something about the stupid casting that didn't fully contact the baffle. Really crappy design! And people think these put out good bass with how leaky the crappy cabinets are?
Here is how the back of the basket looks (see attached pic). When you flick it, the basket rings like a bell. You can see how only the screw holes on the basket are flat and contact the baffle. (I stole the pic from internet, as it's the same looking basket, anyhow).
I filled the gaps between screw holes on the basket with the rope calk, as the roll was huge and had more than enough for 2 woofers. Now it will seal completely. It just so happened, that when I flicked the basket, it was more solid sounding! No more ring! I didn't put the caulk on the whole basket as some have on thier woofers. (I will do that if I go econowave and they play higher) Just the baffle part of basket. I screwed the woofer to the cabinet and it looks ok with only very small amounts of caulk visible (who cares as long as grill is on, and sounds better!).
I had a ton of caulk left over, so I decided to fill anything else that was screwed down. Took the mids out, and they had a rubber backing. Those were good to go!
I took the control/crossover panel off and sealed the baffle. Tweeter, I removed it to seal, but also covered the whole back of the horn just for giggles. It was small, so no loss there even if it didn't help any...
Lastly, I removed the speaker wire terminal on back and sealed it.
Then, came the ultimate test... I tuned off the subwoofer and turned the scope on...
I was only wanting to push them hard to check for leaks, so I started at 80 Hz and worked down. I found a tiny leak in the stupid protection circuit reset button. I am not in mood to deal with it. It is barely audible even if your face is near the baffle and looking at the controls while playing extremely loud and low tones. You have to put your hand right on the protection switch to feel the air. I am ok with that for now. NO OTHER NOISES! I now have a properly sorted bass reflex cabinet! As I test all the way down to 15 Hz, I was surprised at how little port farting there was. My speakers now sound very solid and clean in the 30Hz+ region. Best I have ever owned. I played 25 hz loud enough to bother me, but not enough to cause over excursion just so I could give them some break in time. I did not mess with the stuffing, as the mids are sealed anyways. Only thing left to do with this thing is recap the crossovers and maybe try to get some more bracing in there. If I turn them into Econowaves, I will router the front and rear baffles off so I can make the cabinet a hair bigger internally and use really thick baltic birch baffles (and maybe add 1/4 inch MDF to top, bottom and sides).
After messing with the old D7's, I decided to sit and listen to the speakers with no subs. I was amazed at the difference in the bass! It was so much deeper and cleaner. It was a very audible difference. I still use the sub once in a while but it sounds really good as is. Other than possibly needing a recap, and the old school design of them, I am surprised at how good they sound.
I would say that it was totally worth the effort, and the sound quality has changed from 500 Hz down. The bass seems tighter and much more clean, while there is also very deep bass that is obvious. Not overbearing or loud. I am very pleased with these woofers! The mids and tweet, not so much... I am actually debating whether or not a recap will even help...
Should I save recap money to put towards econowave parts, or just go ahead and recap? I am also worried that mid grade poly caps are going to be larger and won't fit on tiny crossover board. I am going to have to measure......
So..... I go to Home Depot to look for foam strips to put on baffle. Nothing thin enough. I then realized I can use rope caulk. So I bought a roll for 5 bucks. When I took the woofers out to have them re-coned, I knew I was going to have to do something about the stupid casting that didn't fully contact the baffle. Really crappy design! And people think these put out good bass with how leaky the crappy cabinets are?
Here is how the back of the basket looks (see attached pic). When you flick it, the basket rings like a bell. You can see how only the screw holes on the basket are flat and contact the baffle. (I stole the pic from internet, as it's the same looking basket, anyhow).
I filled the gaps between screw holes on the basket with the rope calk, as the roll was huge and had more than enough for 2 woofers. Now it will seal completely. It just so happened, that when I flicked the basket, it was more solid sounding! No more ring! I didn't put the caulk on the whole basket as some have on thier woofers. (I will do that if I go econowave and they play higher) Just the baffle part of basket. I screwed the woofer to the cabinet and it looks ok with only very small amounts of caulk visible (who cares as long as grill is on, and sounds better!).
I had a ton of caulk left over, so I decided to fill anything else that was screwed down. Took the mids out, and they had a rubber backing. Those were good to go!
I took the control/crossover panel off and sealed the baffle. Tweeter, I removed it to seal, but also covered the whole back of the horn just for giggles. It was small, so no loss there even if it didn't help any...
Lastly, I removed the speaker wire terminal on back and sealed it.
Then, came the ultimate test... I tuned off the subwoofer and turned the scope on...
I was only wanting to push them hard to check for leaks, so I started at 80 Hz and worked down. I found a tiny leak in the stupid protection circuit reset button. I am not in mood to deal with it. It is barely audible even if your face is near the baffle and looking at the controls while playing extremely loud and low tones. You have to put your hand right on the protection switch to feel the air. I am ok with that for now. NO OTHER NOISES! I now have a properly sorted bass reflex cabinet! As I test all the way down to 15 Hz, I was surprised at how little port farting there was. My speakers now sound very solid and clean in the 30Hz+ region. Best I have ever owned. I played 25 hz loud enough to bother me, but not enough to cause over excursion just so I could give them some break in time. I did not mess with the stuffing, as the mids are sealed anyways. Only thing left to do with this thing is recap the crossovers and maybe try to get some more bracing in there. If I turn them into Econowaves, I will router the front and rear baffles off so I can make the cabinet a hair bigger internally and use really thick baltic birch baffles (and maybe add 1/4 inch MDF to top, bottom and sides).
After messing with the old D7's, I decided to sit and listen to the speakers with no subs. I was amazed at the difference in the bass! It was so much deeper and cleaner. It was a very audible difference. I still use the sub once in a while but it sounds really good as is. Other than possibly needing a recap, and the old school design of them, I am surprised at how good they sound.
I would say that it was totally worth the effort, and the sound quality has changed from 500 Hz down. The bass seems tighter and much more clean, while there is also very deep bass that is obvious. Not overbearing or loud. I am very pleased with these woofers! The mids and tweet, not so much... I am actually debating whether or not a recap will even help...
Should I save recap money to put towards econowave parts, or just go ahead and recap? I am also worried that mid grade poly caps are going to be larger and won't fit on tiny crossover board. I am going to have to measure......
Attachments
I purchased a seos12 waveguide and a dna360 CD.
I decided to go ahead and build an econowave generic crossover just to get the waveguides up and running. I am calling them "Cerwaves". You will see in another post that the frequency response is obviously not optimal in any way. But at least it's tolerable. Dare I say that the imaging is better than the Cerwin Vegas D7 and the off axis listening is incredible.
As you will see from the FR that the D7 is a mess so I can't do much worse even with a generic crossover 😀
I finally got a measurement mic and decided to start the learning process of measuring and whatnot. I am hoping that I can someday make a new crossover from scratch for the CV woofer. I will buy a better woofer in the future, but I think this will be a good time to start learning as much as I can. Just buying a woofer and pre-designed crossover won't teach me much. It will sound better than what I have now and be more convenient. But first I want to play and learn.
I am using HOLMimpulse.
I do have ARTA/LIMP but am not using it right now for FR. Only for T/S and Le.
I just got everything hooked up yesterday.
Today I tweaked the set up and removed one extra soundcard.
I also moved the stuff to the empty room in the house to see if I could get better measurements (which I did, and removing secondary soundcard decreased noise immensely as well).
Here is the FR of CV in original form. The green/red lines are mid range and tweeter Lpad maxed out. Dark blue line is with the levels flat.
I did not do off axis measurements. When I get to crossover design phase, I will do off axis measurements.
This was taken with speaker off the ground and with tweeter as center. I didn't listen to them like that 😀
Didn't waste my time measuring them from the actual listening axis
I decided to go ahead and build an econowave generic crossover just to get the waveguides up and running. I am calling them "Cerwaves". You will see in another post that the frequency response is obviously not optimal in any way. But at least it's tolerable. Dare I say that the imaging is better than the Cerwin Vegas D7 and the off axis listening is incredible.
As you will see from the FR that the D7 is a mess so I can't do much worse even with a generic crossover 😀
I finally got a measurement mic and decided to start the learning process of measuring and whatnot. I am hoping that I can someday make a new crossover from scratch for the CV woofer. I will buy a better woofer in the future, but I think this will be a good time to start learning as much as I can. Just buying a woofer and pre-designed crossover won't teach me much. It will sound better than what I have now and be more convenient. But first I want to play and learn.
I am using HOLMimpulse.
I do have ARTA/LIMP but am not using it right now for FR. Only for T/S and Le.
I just got everything hooked up yesterday.
Today I tweaked the set up and removed one extra soundcard.
I also moved the stuff to the empty room in the house to see if I could get better measurements (which I did, and removing secondary soundcard decreased noise immensely as well).
Here is the FR of CV in original form. The green/red lines are mid range and tweeter Lpad maxed out. Dark blue line is with the levels flat.
I did not do off axis measurements. When I get to crossover design phase, I will do off axis measurements.
This was taken with speaker off the ground and with tweeter as center. I didn't listen to them like that 😀
Didn't waste my time measuring them from the actual listening axis
Attachments
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I flipped the cabinet upside down so the woofer was up higher.
The waveguide had to come out a bit to match the time alignment of woofer, so I was able to sit it on top of cabinet and move it forward while also letting it hang over edge of cabinet so it is now lower and closer to woofer. I took the front panel off the base of the cabinet. No big deal, as it was messed up a bit anyways. I use the piece I removed to prop the waveguide. I unplugged the woofer from the crossover by just reaching into the huge ports. I ran the new crossover wires through the port. I decided to plug the ports for better integration with the subs.
The waveguide had to come out a bit to match the time alignment of woofer, so I was able to sit it on top of cabinet and move it forward while also letting it hang over edge of cabinet so it is now lower and closer to woofer. I took the front panel off the base of the cabinet. No big deal, as it was messed up a bit anyways. I use the piece I removed to prop the waveguide. I unplugged the woofer from the crossover by just reaching into the huge ports. I ran the new crossover wires through the port. I decided to plug the ports for better integration with the subs.
Attachments
How do they sound with the generic crossover?
Well, if you look at the response, even with the Lpad maxed out on the Cerwave, the highs are still a little low.
I don't like overly bright, BUT I kept turning the Lpad down when I was first messing with volume and waveguide alignment. I thought it was the crossover not being matched to woofer that made it sound not bright, but then I realized after looking at response that I was turning the Lpad down a little because that 2k peak was too loud. After first couple of measurements, I maxed out the Lpad and realized what the issue was. Obviously this crossover is not right for this set up. I knew that when I ordered the parts. This is for noise and put them to use instead of sitting them in the closet for a LONG time 🙁
Now I run them all out and it sounds better in the highs with exception to the 2k peak 🙁
I think people underestimated the midrange sensitivity of these woofers based on what little I have heard online.. I have not seen an actual calibrated SPL and FR of this woofer. I am in unknown territory for that.. I think they are 95 or just a hair under. This crossover is for woofers UNDER 95db sensitivity. So with Lpad maxed out and highs not being enough, I guess these are closer to 95 or maybe a bit over in midrange. Bass, I don't know as I can't measure accurately in a room. Wish I could.
I am hoping that by not running them deep I might get a little more sensitivity with a small sealed cabinet. Winisd with my measured T/S parameters says these will do great to 70hz with a sealed 1.3 cubic feet. Exactly what I want. Which is why I want to keep playing with the woofers.
And of course... How do they compare to the D7 in original form?
Well, just based on the waveguide and compression driver design, there is obvious improvement.
Immediately upon listening to the Cerwaves I knew the crossover was not right. But it did not sound bad. Just off a little. My ears are just experienced enough to hear when something is off. I could hear the original D7 issues right away as well. I have new crossover components for the waveguide, but the D7 still has old caps, so that could be a slight factor in it's issue as well. I can tell from the FR now that having it a WMTM 3 way with 2 different midranges makes for even more driver integration issues. Yes, there is an issue with my Cerwave, but you can see it's only in one place, not 2 places like the D7 😀 Also, the waveguide and tweeter work so awesome together and are much flatter than what the D7 drivers can do that it's even obvious in the FR.
So, apples to oranges, the Cerwaves still taste better and don't cause a headache. The imaging on the D7's was not all that good. Off axis was bad. Small on axis listening position. The Cerwaves killed anything I have ever owned on that factor. Crazy imaging off axis and big listening sweet spot when toed in correctly!
One similarity, was it's ability to play loud cleanly. The dual high sensitivity midranges crossed over high at 600 made them very loud. So not much improvement there. The tweeter quality difference is night and day, even thought the D7 has a compression driver. It's just too small and not flat at all.
Seeing the FR of both helped me get an idea of why the Cerwaves didn't hit the highs as loud. The Cerwaves have WAY WAY WAY more potential, though. I can't do much with a 3 way without a lot of work, and the crossover will cost a lot more. The waveguide and CD are just too high of quality to try to ever make it worth working with the original D7 mids and tweet.
The crossover points of the D7 are 600 and 3.5k Hz.
The econowave crossover is 1.2 on woofer and 3k on the cd! I think it's 2k acoustic.
Here is the FR of the CV 12" woofer. I still don't know what it's sensitivity is.
I haven't gotten that far in my software/hardware measurement adventure, yet.
It is running full range.
Well, if you look at the response, even with the Lpad maxed out on the Cerwave, the highs are still a little low.
I don't like overly bright, BUT I kept turning the Lpad down when I was first messing with volume and waveguide alignment. I thought it was the crossover not being matched to woofer that made it sound not bright, but then I realized after looking at response that I was turning the Lpad down a little because that 2k peak was too loud. After first couple of measurements, I maxed out the Lpad and realized what the issue was. Obviously this crossover is not right for this set up. I knew that when I ordered the parts. This is for noise and put them to use instead of sitting them in the closet for a LONG time 🙁
Now I run them all out and it sounds better in the highs with exception to the 2k peak 🙁
I think people underestimated the midrange sensitivity of these woofers based on what little I have heard online.. I have not seen an actual calibrated SPL and FR of this woofer. I am in unknown territory for that.. I think they are 95 or just a hair under. This crossover is for woofers UNDER 95db sensitivity. So with Lpad maxed out and highs not being enough, I guess these are closer to 95 or maybe a bit over in midrange. Bass, I don't know as I can't measure accurately in a room. Wish I could.
I am hoping that by not running them deep I might get a little more sensitivity with a small sealed cabinet. Winisd with my measured T/S parameters says these will do great to 70hz with a sealed 1.3 cubic feet. Exactly what I want. Which is why I want to keep playing with the woofers.
And of course... How do they compare to the D7 in original form?
Well, just based on the waveguide and compression driver design, there is obvious improvement.
Immediately upon listening to the Cerwaves I knew the crossover was not right. But it did not sound bad. Just off a little. My ears are just experienced enough to hear when something is off. I could hear the original D7 issues right away as well. I have new crossover components for the waveguide, but the D7 still has old caps, so that could be a slight factor in it's issue as well. I can tell from the FR now that having it a WMTM 3 way with 2 different midranges makes for even more driver integration issues. Yes, there is an issue with my Cerwave, but you can see it's only in one place, not 2 places like the D7 😀 Also, the waveguide and tweeter work so awesome together and are much flatter than what the D7 drivers can do that it's even obvious in the FR.
So, apples to oranges, the Cerwaves still taste better and don't cause a headache. The imaging on the D7's was not all that good. Off axis was bad. Small on axis listening position. The Cerwaves killed anything I have ever owned on that factor. Crazy imaging off axis and big listening sweet spot when toed in correctly!
One similarity, was it's ability to play loud cleanly. The dual high sensitivity midranges crossed over high at 600 made them very loud. So not much improvement there. The tweeter quality difference is night and day, even thought the D7 has a compression driver. It's just too small and not flat at all.
Seeing the FR of both helped me get an idea of why the Cerwaves didn't hit the highs as loud. The Cerwaves have WAY WAY WAY more potential, though. I can't do much with a 3 way without a lot of work, and the crossover will cost a lot more. The waveguide and CD are just too high of quality to try to ever make it worth working with the original D7 mids and tweet.
The crossover points of the D7 are 600 and 3.5k Hz.
The econowave crossover is 1.2 on woofer and 3k on the cd! I think it's 2k acoustic.
Here is the FR of the CV 12" woofer. I still don't know what it's sensitivity is.
I haven't gotten that far in my software/hardware measurement adventure, yet.
It is running full range.
Attachments
Same over here in USA, but thinking it will be around for a while.
Its not bad for a re-retrofit, or easy fix for a lousy cutout, other than that, it's messy.
PE has gasket tape - btw.
Its not bad for a re-retrofit, or easy fix for a lousy cutout, other than that, it's messy.
PE has gasket tape - btw.
Home Depot sells the rope caulk. I was surprised when I found it, as that is what I used when I was younger. I am ordering more things from PE now, so will use the tape next time. Just didn't want to order anything when I first worked on the CV.
I have not done nearfield. Do you think it is important?
Do I not have to worry as much about bounderies like walls and stuff? This will allow me to measure in the living room without moving the speaker around too much if the nearfield is more forgiving. I just got the mic the other day, so am COMPLETELY green and new to measurement. I am using HOLMimpulse.
I measured at about 1 meter from center of woofer for the measurement you see.
Off the ground to get woofer farther from floor. Center of woofer was over 4 feet off the ground, in a room hat has 9 foot ceilings.
The complete tweeter/woofer measurement was from listening axis.
How close is a nearfield measurement, and how loud does it need to be?
(I am researching nearfield right now, and reading ARTA pdf)
I was mainly measuring to see what I need to learn about crossover points.
I do plan on learning PCD or something similar. I really want to use these drivers (cv woofer and seos12/dna360) and set up to learn to do crossovers. That is one of the harder things to learn from what I see.
Z offset, minimum phase, notch filters, zobels. Man. I have a lot to learn 😀
This measurement gear is making me want to test all the original D7 drivers and see what else I can do with them. More for learning than trying to make perfect speakers. If I fail, it won't matter. I can sell the speakers off 😀 This is why I am not fixing them up (new thicker baffles and bracing).
I was not horribly serious when I started this thread. I am very serious now about working with the SEOS12/DNA360 and CV woofer so I can learn PCD and measuring speakers.
If people think I should start a new, more serious thread, I will. I need help learning. I have the stuff, just need help walking through it all the first time. I am more of a hands on, switch flipper type than a read a ton and do formulas type. Yes, I do read technical manuals. I am also starting the process of talking to people in multiple forums as I start to learn the various programs I need to use. Now that I have measuring gear, I can get data for people to help me analyze. I don't want anyone to "design" stuff for me. I am hoping I can find someone to help me learn to see what is looked at in the data, and how to manipulate and compensate. I can't go active right now, and am kinda poor. This means my learning curve is slowed down due to lack of expendable income (caps, coils, etc).
I will get there little by little.
Just need help with best measurement techniques and also with properly analyzing the data.
My next plan was to get some fiberglass insulation for the CV, as I am using them sealed (ports plugged) with subs. I do plan on making a much smaller enclosures if the woofers work out. I don't want to hack up this enclosure in case I decide to sell them. There is really thin, flimsy batting stapled to the walls of enclosure. Not even sure what it is. Might be wool. Not enough to do much as far as I can tell. It's like 1/4 inch thick. The dept of the cabinet now is 12 inches internally. Not good. This would put a resonance at about 1.2k or so. This is right in the range of the crossover. I am going to HD to see if I can afford a little fiberglass. It's cheap, but I am that broke 😀
I also plan on taking measurements as I experiment with things like baffles, stuffing and whatnot.
Help me, help you, help myself 😀
Thanks to anyone that helps me learn. I appreciate it.
Todd
I have not done nearfield. Do you think it is important?
Do I not have to worry as much about bounderies like walls and stuff? This will allow me to measure in the living room without moving the speaker around too much if the nearfield is more forgiving. I just got the mic the other day, so am COMPLETELY green and new to measurement. I am using HOLMimpulse.
I measured at about 1 meter from center of woofer for the measurement you see.
Off the ground to get woofer farther from floor. Center of woofer was over 4 feet off the ground, in a room hat has 9 foot ceilings.
The complete tweeter/woofer measurement was from listening axis.
How close is a nearfield measurement, and how loud does it need to be?
(I am researching nearfield right now, and reading ARTA pdf)
I was mainly measuring to see what I need to learn about crossover points.
I do plan on learning PCD or something similar. I really want to use these drivers (cv woofer and seos12/dna360) and set up to learn to do crossovers. That is one of the harder things to learn from what I see.
Z offset, minimum phase, notch filters, zobels. Man. I have a lot to learn 😀
This measurement gear is making me want to test all the original D7 drivers and see what else I can do with them. More for learning than trying to make perfect speakers. If I fail, it won't matter. I can sell the speakers off 😀 This is why I am not fixing them up (new thicker baffles and bracing).
I was not horribly serious when I started this thread. I am very serious now about working with the SEOS12/DNA360 and CV woofer so I can learn PCD and measuring speakers.
If people think I should start a new, more serious thread, I will. I need help learning. I have the stuff, just need help walking through it all the first time. I am more of a hands on, switch flipper type than a read a ton and do formulas type. Yes, I do read technical manuals. I am also starting the process of talking to people in multiple forums as I start to learn the various programs I need to use. Now that I have measuring gear, I can get data for people to help me analyze. I don't want anyone to "design" stuff for me. I am hoping I can find someone to help me learn to see what is looked at in the data, and how to manipulate and compensate. I can't go active right now, and am kinda poor. This means my learning curve is slowed down due to lack of expendable income (caps, coils, etc).
I will get there little by little.
Just need help with best measurement techniques and also with properly analyzing the data.
My next plan was to get some fiberglass insulation for the CV, as I am using them sealed (ports plugged) with subs. I do plan on making a much smaller enclosures if the woofers work out. I don't want to hack up this enclosure in case I decide to sell them. There is really thin, flimsy batting stapled to the walls of enclosure. Not even sure what it is. Might be wool. Not enough to do much as far as I can tell. It's like 1/4 inch thick. The dept of the cabinet now is 12 inches internally. Not good. This would put a resonance at about 1.2k or so. This is right in the range of the crossover. I am going to HD to see if I can afford a little fiberglass. It's cheap, but I am that broke 😀
I also plan on taking measurements as I experiment with things like baffles, stuffing and whatnot.
Help me, help you, help myself 😀
Thanks to anyone that helps me learn. I appreciate it.
Todd
I pulled speaker out a little farther into room from listening position to measure near field response. Much easier than dragging into other room.
Put microphone a few mm from the woofer cone.
The dips in response threw me off at first. I read the ARTA pdf on nearfield measurements, and quickly learned that dips are caused by the cone itself. Completely normal and can be calculated. The nearfield is good for bass response. Not so much for higher frequency as far as I can tell.
I am posting a picture with the woofer response, and with the combined response of the SEOS12 with woofer. To see how it would look with bass. Bass looks pretty good.
Here is what I found odd. I measured with the port open and plugged.
The response actually was increased and deeper in the lower frequencies with the ports plugged.
I thought that sealed would provide less deep bass. Odd. I don't know how the nearfield measurements are being effected by the room. I will find out some other time when I do far field outside measurements for bass.
The green line is the ported response. Red is sealed.
Put microphone a few mm from the woofer cone.
The dips in response threw me off at first. I read the ARTA pdf on nearfield measurements, and quickly learned that dips are caused by the cone itself. Completely normal and can be calculated. The nearfield is good for bass response. Not so much for higher frequency as far as I can tell.
I am posting a picture with the woofer response, and with the combined response of the SEOS12 with woofer. To see how it would look with bass. Bass looks pretty good.
Here is what I found odd. I measured with the port open and plugged.
The response actually was increased and deeper in the lower frequencies with the ports plugged.
I thought that sealed would provide less deep bass. Odd. I don't know how the nearfield measurements are being effected by the room. I will find out some other time when I do far field outside measurements for bass.
The green line is the ported response. Red is sealed.
Attachments
When you do a NF response, you don't play the test signal loud. In that way the woofer's interaction with the room will be negligable. That's the whole idea behind NF testing - you get just the woofer's response and not any room interactions.
What you got with the green and red roll off is what's to be expected when comparing AS to ported (e.g. 6 dB/octave roll off for A.S. and 12 dB roll off for vented)
What you got with the green and red roll off is what's to be expected when comparing AS to ported (e.g. 6 dB/octave roll off for A.S. and 12 dB roll off for vented)
HOLMimpulse has a meter to let me know if I am playing the correct level. I just made sure it was set correctly. Only took me a minute to do a couple quick tests and turn the volume knob.
I was reading that you are supposed to measure the response of the port and add it to the response of the woofer. I didn't waste my time figuring that out, as I didn't really care about the deep bass. Anything above 80 to 100 is fine with me. Some other time I will mess around with it, just so I understand it. Maybe when I get around to measuring frequency response with stuffing.
It's nice to see the FR is matching up with what winisd basically calculated for the sealed box. Ported will roll off steeper, but the AS will roll off much sooner. So, that doesn't match with what the FR shows. At port tuning frequency, the AS should be around 5 db lower. I am assuming summing the FR of the port will bring that up to correct level.
Here is a pic of the winisd calculations based on my LIMP measurements, and the parameters of the cabinet with port open and sealed.
I was reading that you are supposed to measure the response of the port and add it to the response of the woofer. I didn't waste my time figuring that out, as I didn't really care about the deep bass. Anything above 80 to 100 is fine with me. Some other time I will mess around with it, just so I understand it. Maybe when I get around to measuring frequency response with stuffing.
It's nice to see the FR is matching up with what winisd basically calculated for the sealed box. Ported will roll off steeper, but the AS will roll off much sooner. So, that doesn't match with what the FR shows. At port tuning frequency, the AS should be around 5 db lower. I am assuming summing the FR of the port will bring that up to correct level.
Here is a pic of the winisd calculations based on my LIMP measurements, and the parameters of the cabinet with port open and sealed.
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I have been on some measurement adventures on my way to learning how to build passive crossovers. Once I get my data ready, I will start getting prepared to use PCD7. That is when all the questions are really going to start.
I measure the Le of both drivers. I have zma files ready as well as the frd files.
I decided to measure the drivers on the tweeter axis.
First I checked to make sure the Tweeter was perfectly time aligned. I can move the waveguide back and forth.
I measure the woofer alone with no crossover on axis, off 22.5 degrees (roughly) and 45 degrees.
I repeated the process with the seos12/360 and then everything together with crossover in the CERWAVE speaker set up.
I also took the woofer out of the cabinet to do an Le measurement, and decided to check the frequency response out of the cabinet.
I placed the woofer on a couple of pillows to help floor reflection a bit.
To my surprise, the big dip at 1.2k went away! I think its a combination of baffle and the 12 inch cabinet depth. I included the FR graph of that.
There is virtually NO stuffing in the CV enclosure. Still working on that. They are 3.2 cubic feet and I don't really want to buy enough to fill two of them right now. But I will measure when I do.
Tomorrow I am going to see what the SPL difference is between the woofer and the SEOS. I have not measured the difference. I don't have an spl meter.
I measure the Le of both drivers. I have zma files ready as well as the frd files.
I decided to measure the drivers on the tweeter axis.
First I checked to make sure the Tweeter was perfectly time aligned. I can move the waveguide back and forth.
I measure the woofer alone with no crossover on axis, off 22.5 degrees (roughly) and 45 degrees.
I repeated the process with the seos12/360 and then everything together with crossover in the CERWAVE speaker set up.
I also took the woofer out of the cabinet to do an Le measurement, and decided to check the frequency response out of the cabinet.
I placed the woofer on a couple of pillows to help floor reflection a bit.
To my surprise, the big dip at 1.2k went away! I think its a combination of baffle and the 12 inch cabinet depth. I included the FR graph of that.
There is virtually NO stuffing in the CV enclosure. Still working on that. They are 3.2 cubic feet and I don't really want to buy enough to fill two of them right now. But I will measure when I do.
Tomorrow I am going to see what the SPL difference is between the woofer and the SEOS. I have not measured the difference. I don't have an spl meter.
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I measured the waveguide/cd and woofer together and separate without crossover.
I did not touch anything when measuring. Just set the volume for the waveguide and hoped the woofer would play well above noise floor, which it did! I wanted to see what the sensitivity difference was between the two drivers. I also measured them together so I could use the response in an overlay on PCD7.
Here is the current issue I am having.
I am not entirely sure how to enter what I see in the econowave x-over schematic into PCD. I have been able to enter most of the x-over and the sim is getting close, but I don't know where to enter the 16 ohm resistor in PCD. I think I figured out the 8 ohm Lpad.
I am including screen shots of what I am seeing in the hopes someone can help me out.
Right now I am more worried about entering schematics so I can see what different waveguide type crossovers do. I am not worried about altering or playing around with the individual components. Just learning to enter the info into PCD7. I am learning, albeit slowly.
I did try a zoble, and it reduced the impedence peak at 1.7k on the woofer. But I am not using it as I want to stay with what is in the crossover I am using now. As it is in the schematic.
If you look at the PCD screen shot, you can see I highlighted the R14 entry. I am assuming this is where I should put the 16 ohm resistor. But it won't take my entry. I must be doing something wrong. Where does the 16 ohm resistor go in PCD7, as it is in the econowave schematic?
Thanks.
Todd
I did not touch anything when measuring. Just set the volume for the waveguide and hoped the woofer would play well above noise floor, which it did! I wanted to see what the sensitivity difference was between the two drivers. I also measured them together so I could use the response in an overlay on PCD7.
Here is the current issue I am having.
I am not entirely sure how to enter what I see in the econowave x-over schematic into PCD. I have been able to enter most of the x-over and the sim is getting close, but I don't know where to enter the 16 ohm resistor in PCD. I think I figured out the 8 ohm Lpad.
I am including screen shots of what I am seeing in the hopes someone can help me out.
Right now I am more worried about entering schematics so I can see what different waveguide type crossovers do. I am not worried about altering or playing around with the individual components. Just learning to enter the info into PCD7. I am learning, albeit slowly.
I did try a zoble, and it reduced the impedence peak at 1.7k on the woofer. But I am not using it as I want to stay with what is in the crossover I am using now. As it is in the schematic.
If you look at the PCD screen shot, you can see I highlighted the R14 entry. I am assuming this is where I should put the 16 ohm resistor. But it won't take my entry. I must be doing something wrong. Where does the 16 ohm resistor go in PCD7, as it is in the econowave schematic?
Thanks.
Todd
Attachments
I was bored, so bought some fiberglass insulation and lined the cabinets pretty well.
I sealed the ports and am using subs, so not worried about losing bass from overstuffing.
The cabinets only had 1/4" thick batting stapled to the walls.
I mainly stuffed them to help with internal waves and possibly help a little with baffle difraction.
I noticed a huge improvement in the upper midrange!
I will measure eventually to see what was effected.
I doubt the 1.7k hump was fixed, but maybe the dip just above 1k might be better.
That dip is caused by baffle diffraction/cabinet. Not there with bare open air woofer...
I do notice a slight dip in midbass response, but it's very smooth and not lacking.
I don't like how much of a waste the cabinets are (the woofers only need 1.3 ft3 if sealed and used with subs). They are 3.2 ft3 each!
But so far, so good. 🙂
Little by little.
Fun to play with until I get rid of them, and get better woofers and build smaller cabinets.
I sealed the ports and am using subs, so not worried about losing bass from overstuffing.
The cabinets only had 1/4" thick batting stapled to the walls.
I mainly stuffed them to help with internal waves and possibly help a little with baffle difraction.
I noticed a huge improvement in the upper midrange!
I will measure eventually to see what was effected.
I doubt the 1.7k hump was fixed, but maybe the dip just above 1k might be better.
That dip is caused by baffle diffraction/cabinet. Not there with bare open air woofer...
I do notice a slight dip in midbass response, but it's very smooth and not lacking.
I don't like how much of a waste the cabinets are (the woofers only need 1.3 ft3 if sealed and used with subs). They are 3.2 ft3 each!
But so far, so good. 🙂
Little by little.
Fun to play with until I get rid of them, and get better woofers and build smaller cabinets.
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