Hello all, I've finally finished my set of speakers. This was my attempt to go all out. Before this project i've only built a few cheaper designs.
Firstly I have to add felt to the sides of the drivers for diffraction effects. (I'm router impaired and can't flush mount for my life).
The design is a 3-way using the dayton RS225, RS52 dome midrange, and the vifa xt19 tweeter. I have made no measurements yet but will soon once my microphone capsules arrive. It sounds great, but a bit different. Some recordings sound horrible through it while others are amazing. The treble is a tad bright for my tastes. There is just something minor wrong somewhere that I have to pinpoint in the crossover. Perhaps i should wait till measurements before making any judgements. Anyways i'm pretty satisfied with the project. Any comments, criticisms appreciated.
Firstly I have to add felt to the sides of the drivers for diffraction effects. (I'm router impaired and can't flush mount for my life).
The design is a 3-way using the dayton RS225, RS52 dome midrange, and the vifa xt19 tweeter. I have made no measurements yet but will soon once my microphone capsules arrive. It sounds great, but a bit different. Some recordings sound horrible through it while others are amazing. The treble is a tad bright for my tastes. There is just something minor wrong somewhere that I have to pinpoint in the crossover. Perhaps i should wait till measurements before making any judgements. Anyways i'm pretty satisfied with the project. Any comments, criticisms appreciated.
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Yea the dayton dome seems to have good measurements. According to zaph and Mark K. One of the reasons why i got it. Also its very cheap at $30. Its convenient too since you don't need a rear chamber. I put everything in a 1 cu ft. MTM cabinet from partsexpress since my woodworking skills suck. The midrange sounds really nice. I can't really describe it as anything other than just neutral. You can cross the mid relatively low around 500hz but it depends on how much output you need.
Hi
I am building a 3- or 3.5-way too. I considered the XT19 (my current first choice), but have to make do with what I have, which is the RS D28 shielded tweeter. My other drivers are RS52 and 2x Extremis 6.8.
I'm glad to hear that one can use the RS52 so low down. My intention is to cross at 800Hz. I listened to it without a crossover, and it's amazing how high up it extends to.
I am building a 3- or 3.5-way too. I considered the XT19 (my current first choice), but have to make do with what I have, which is the RS D28 shielded tweeter. My other drivers are RS52 and 2x Extremis 6.8.
I'm glad to hear that one can use the RS52 so low down. My intention is to cross at 800Hz. I listened to it without a crossover, and it's amazing how high up it extends to.
Don't be surprised to find huge deviations from your predicted response once you measure them. I've built two 2-way's so far, and in both cases made mistakes that were only clear when measured.
It appears the crossover point for your dome midrange is in the right place where you will not need a BFC circuit. Instead, you will probably have to pad down the midrange dome and tweeter to achieve a good tonal balance.
Dan
It appears the crossover point for your dome midrange is in the right place where you will not need a BFC circuit. Instead, you will probably have to pad down the midrange dome and tweeter to achieve a good tonal balance.
Dan
Yes that dome midrange is very nice. I have a few concerns about my speakers. I haven't yet gotten around to any measurements or felt treatments.
1. Anyone that has done what i'm trying to do which is put a layer of felt around the drivers to make it flush, does this work just as well or better than having it flush mounted in the first place?
2. My design has series resistors before the crossover...how exactly do resistor power handling ratings work. For example if i have a 10 watt resistor what does that rating mean exactly, how much power can it really handle?
1. Anyone that has done what i'm trying to do which is put a layer of felt around the drivers to make it flush, does this work just as well or better than having it flush mounted in the first place?
2. My design has series resistors before the crossover...how exactly do resistor power handling ratings work. For example if i have a 10 watt resistor what does that rating mean exactly, how much power can it really handle?
I don't have any experience with felt as a means of reducing diffraction effects. I usually model the speaker using the Baffle Diffraction Simulator, and make my driver placement based on this analysis. I would suggest that you first measure your speaker on- and off-axis to see just how much diffraction is taking place.
I suspect, though, that if you don't flush-mount the drivers, the discontinuity where the driver edge meets the felt will cause early diffraction. This will likely cause the upper frequencies to have a ragged response. But it's just a guess...
Another method of reducing diffraction (with drivers surface mounted as in your case) is to make a grille from solid wood/MDF/hardboard about the same thickness as the driver flanges. The speaker cutouts are just slightly larger than the outer edge of the drivers. This will be the equivalent of flush mounting. In some cases I've seen the inner edges of these grilles bevelled or curved where the driver flange thickness was smaller than the grille thickness.
I suspect, though, that if you don't flush-mount the drivers, the discontinuity where the driver edge meets the felt will cause early diffraction. This will likely cause the upper frequencies to have a ragged response. But it's just a guess...
Another method of reducing diffraction (with drivers surface mounted as in your case) is to make a grille from solid wood/MDF/hardboard about the same thickness as the driver flanges. The speaker cutouts are just slightly larger than the outer edge of the drivers. This will be the equivalent of flush mounting. In some cases I've seen the inner edges of these grilles bevelled or curved where the driver flange thickness was smaller than the grille thickness.
1. Felt is good, flush is better.
2. A 10W resistor can dissipate just that. 10W safely for some time. Lets say we are using a 2 Ohm 10W resistor feeding an 8 Ohm 20W (true RMS) tweeter above 3kHz. The crossover is going to feed about 17W for HF when running flat out a 100W amp with music. 2/8 of that is going to be dissipated by the resistor. I.e. peanuts.
2. A 10W resistor can dissipate just that. 10W safely for some time. Lets say we are using a 2 Ohm 10W resistor feeding an 8 Ohm 20W (true RMS) tweeter above 3kHz. The crossover is going to feed about 17W for HF when running flat out a 100W amp with music. 2/8 of that is going to be dissipated by the resistor. I.e. peanuts.
Is there any possibility that i could get you to post up your xover desin.
I'm considering a RS225, RS52, x design soon and would like a good place to start with the overall xover points and such. What are your respective xover points and slopes with the passive in that, and how do you avoid beaming using a dome midrange in the home. (i'm using one in my car)
I'm considering a RS225, RS52, x design soon and would like a good place to start with the overall xover points and such. What are your respective xover points and slopes with the passive in that, and how do you avoid beaming using a dome midrange in the home. (i'm using one in my car)
I used a 1 cubic ft. MTM partsexpress enclosure. Please do not try this. the baffle will not accomadate it. It was a stupid idea but in the end it worked out. Digikey finally has the panasonic capsules, so i'll measure it as soon as possible but i've been busy with school. I'm also thinking of adding a RLC notch to get of the impedence peak in the XT19.
demon, I'll post a crossover schematic soon.
demon, I'll post a crossover schematic soon.
Thanks Angsuman,
No rush on posting the schematic really, will be ordering my RS52's here in the next week-week.5. I already have my RS225-8, and a few tweets that are on the block to be possibly used in the design.
I was possibly thinking of some very nice drop in tweets that would give me very good results, i already have a LPG 26nafm that i absolutely am in love with, so i thought about possibly using it. I also have a pair of Neo3's that i could possibly use, but biggest deciding factor is most likely imp, and xover points.
Really wanting to stick with a proven xover design for a 3way, and get the best bang/buck, as well as an overall rather effecient network ~75w @4ohms available for now.
No rush on posting the schematic really, will be ordering my RS52's here in the next week-week.5. I already have my RS225-8, and a few tweets that are on the block to be possibly used in the design.
I was possibly thinking of some very nice drop in tweets that would give me very good results, i already have a LPG 26nafm that i absolutely am in love with, so i thought about possibly using it. I also have a pair of Neo3's that i could possibly use, but biggest deciding factor is most likely imp, and xover points.
Really wanting to stick with a proven xover design for a 3way, and get the best bang/buck, as well as an overall rather effecient network ~75w @4ohms available for now.
This is the schematic I believe its accurate but you might want to check it in a circuit design program or PCD. I didn't draw a schematic
So if you don't already have PCD go to http://www.pvconsultants.com/audio/crossover/pcd.htm
and download it. In the layouts folder there will be 3 circuit diagrams HP LP and mid. Use these to find where in the circuit they are.
woofer
L2=3.00 mH
C2= 40 uf
C5=5.10uf
R7= 10 ohm
tweeter
c9= 10uf
L9=.10 mH
C10= 40uf
R10=3.50 ohm
midrange
C16=20 uf
L16=1.20 mH
C17=40uf
L18=0.25mH
C18= 10 uf
L19=.70 uf
R19=8 ohm
C21=20 uf
R29=10 ohm
So if you don't already have PCD go to http://www.pvconsultants.com/audio/crossover/pcd.htm
and download it. In the layouts folder there will be 3 circuit diagrams HP LP and mid. Use these to find where in the circuit they are.
woofer
L2=3.00 mH
C2= 40 uf
C5=5.10uf
R7= 10 ohm
tweeter
c9= 10uf
L9=.10 mH
C10= 40uf
R10=3.50 ohm
midrange
C16=20 uf
L16=1.20 mH
C17=40uf
L18=0.25mH
C18= 10 uf
L19=.70 uf
R19=8 ohm
C21=20 uf
R29=10 ohm
Yes as a matter of fact it did turn out good, I adding some felt damping around the tweeters, because I can't flush mount, and I added an RLC notch filter to the Vifa XT19 to lower the impedance peak at resonance.
Sadly, I still have trouble soldering panasonic capsules, but I took a measurement with a computer mic to make sure things were at least in phase. I'm not sure how accurate this measurement is but it is in my room with ARTA using pink noise.
Sadly, I still have trouble soldering panasonic capsules, but I took a measurement with a computer mic to make sure things were at least in phase. I'm not sure how accurate this measurement is but it is in my room with ARTA using pink noise.
Attachments
Here are some links to images,
http://photos-c.ak.facebook.com/photos-ak-sf2p/v56/146/94/1324170172/n1324170172_30002998_1951.jpg
http://photos-172.ll.facebook.com/photos-ll-sf2p/v56/146/94/1324170172/n1324170172_30003005_4100.jpg
http://photos-172.ll.facebook.com/photos-ll-sf2p/v56/146/94/1324170172/n1324170172_30003012_5969.jpg
http://photos-172.ll.facebook.com/photos-ll-sf2p/v56/146/94/1324170172/n1324170172_30003023_8877.jpg
I should take a new picture with the felt in place...
http://photos-c.ak.facebook.com/photos-ak-sf2p/v56/146/94/1324170172/n1324170172_30002998_1951.jpg
http://photos-172.ll.facebook.com/photos-ll-sf2p/v56/146/94/1324170172/n1324170172_30003005_4100.jpg
http://photos-172.ll.facebook.com/photos-ll-sf2p/v56/146/94/1324170172/n1324170172_30003012_5969.jpg
http://photos-172.ll.facebook.com/photos-ll-sf2p/v56/146/94/1324170172/n1324170172_30003023_8877.jpg
I should take a new picture with the felt in place...
Well in Passive Crossover Designer, I kind of tried to voice it with a bit of a dip in the treble. I find most flat designs far too bright. Also many recordings feel too bright to me so that's why I tried tailoring the response down a few dB at last octave. The PC mic probably has a bit of a droop of course, but I find it interesting that its still relatively flat in room with that simple microphone. Surely, I've done something right.
The reason I try to voice it down a bit is probably because I'm kind of young, I'm 17 and can hear all the way out to 20 khz. Sounds between 10-20khz, that are too high in level are extremely painful. I can feel a tickle right under my chin, as well as the feeling of having my eardrum pushed in and then slowly have it recover. The ear also feels like its being tickled and Its almost like tasting a metallic taste in my mouth.
Yeah I know a bit weird I guess, maybe to older people my design will be too dull, but right now its perfect for me. I wish I could do distortion testing because the RLC notch filter seems to have made a difference in the highs, even though I try hard not to imagine things.
The reason I try to voice it down a bit is probably because I'm kind of young, I'm 17 and can hear all the way out to 20 khz. Sounds between 10-20khz, that are too high in level are extremely painful. I can feel a tickle right under my chin, as well as the feeling of having my eardrum pushed in and then slowly have it recover. The ear also feels like its being tickled and Its almost like tasting a metallic taste in my mouth.
Yeah I know a bit weird I guess, maybe to older people my design will be too dull, but right now its perfect for me. I wish I could do distortion testing because the RLC notch filter seems to have made a difference in the highs, even though I try hard not to imagine things.
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