I'm trying to fix / improve a 3-way speaker.
I need suggestions for finding a cheap midwoofer who can work between 100 (200) Hz and 7-9kHz. No need to be the best speaker, should be above 86dB sensitivity on sealed box and to be cheap and easy to find.
Box consists of one tweeter, two midbass of 6,5" and a (sub) woofer of 10" placed on side. It is a floorstander.
Tweeter has already changed with SAL DTF 12 and for the bass I only have the measurements made on his vented box.
The impedance of woofer is 8Ω.
The measurements show that will be difficult to use it over 150-200Hz.
Finally I want to get actually a 2-way speaker till 100Hz (maybe cutted at 100Hz) and to extend the range of bass with the vented subwoofer.
I know that the information provided are insufficient to make recommendations but I hope to get some ideas even.
I have no experience with speakers and so I rely on you guys
I need suggestions for finding a cheap midwoofer who can work between 100 (200) Hz and 7-9kHz. No need to be the best speaker, should be above 86dB sensitivity on sealed box and to be cheap and easy to find.
Box consists of one tweeter, two midbass of 6,5" and a (sub) woofer of 10" placed on side. It is a floorstander.
Tweeter has already changed with SAL DTF 12 and for the bass I only have the measurements made on his vented box.
The impedance of woofer is 8Ω.
The measurements show that will be difficult to use it over 150-200Hz.
Finally I want to get actually a 2-way speaker till 100Hz (maybe cutted at 100Hz) and to extend the range of bass with the vented subwoofer.
I know that the information provided are insufficient to make recommendations but I hope to get some ideas even.
I have no experience with speakers and so I rely on you guys
Look for Monacor SPH series .
Maybe they're too good
SPH 135 or 165
Check the impedance. Some models are available in 4 or 8 Ω -not the SPH ( only the SPH 30 ) series, which feature some double coil models ( it could be useful if your midranges are 8 Ω and parallel connected = 4Ω and you want to substitute them with a single unit without reworking all the crossover network )
Maybe they're too good
SPH 135 or 165Check the impedance. Some models are available in 4 or 8 Ω -not the SPH ( only the SPH 30 ) series, which feature some double coil models ( it could be useful if your midranges are 8 Ω and parallel connected = 4Ω and you want to substitute them with a single unit without reworking all the crossover network )
ses,
What you are asking we really can't answer. You have set constraints that NO driver for any money can satisfy. Why are you looking for a two mid-base system? Why are you picking 7 to 9K crossover? If cost is an issue, use one mid-bass and bring the crossover down to a reasonable point like 2 to 3K.
Full range speakers are not full range and anything resembling sound at 7 to 9 K is mostly cone breakup. Vile expensive things designed to do more than a single driver can do. A mid-bass that can do 7K would be something like the Fountek FE85 3 inch. FR88 better but it costs more than decent cheap 6 inchers like the Silver Flute that will do just fine from 80 to 2K ( with modification) where most any half-decent tweeter can take over. The 3 inch is fine for a desktop, but it won't move the air for a full size monitor unless it was used above 500 or so.
What you are asking we really can't answer. You have set constraints that NO driver for any money can satisfy. Why are you looking for a two mid-base system? Why are you picking 7 to 9K crossover? If cost is an issue, use one mid-bass and bring the crossover down to a reasonable point like 2 to 3K.
Full range speakers are not full range and anything resembling sound at 7 to 9 K is mostly cone breakup. Vile expensive things designed to do more than a single driver can do. A mid-bass that can do 7K would be something like the Fountek FE85 3 inch. FR88 better but it costs more than decent cheap 6 inchers like the Silver Flute that will do just fine from 80 to 2K ( with modification) where most any half-decent tweeter can take over. The 3 inch is fine for a desktop, but it won't move the air for a full size monitor unless it was used above 500 or so.
Thank you for feedback.
My question was more theoretical because I had come to the same conclusion like you tvrgeek., but I was not sure.
Luckily I managed to get some reasonable results using the original speakers, lowering significantly the cutoff frequency of the tweeter filter to around 5KHz, and using some notch filtering (paralel with the speakers) for uper side of mid's.
The main problem now are the impedance of speakers that become to low between 800Hz and 5KHz. The mean value of impedance is ~8.2Ω but in this range the lower peak it is around 3Ω.
The measured distorsions are resonable low with a narrow peak at ~5KHz were are double compared to the rest of the band.
For the moment I will stay like this and listen to see if it is need to be changed or not.
To increase the impedance for mid range I tried with notch in series with the mid speaker but the results was not so nice to my ears. Maybe you have some idea how to increase the impedance for this mid band.
Thank you.
My question was more theoretical because I had come to the same conclusion like you tvrgeek., but I was not sure.
Luckily I managed to get some reasonable results using the original speakers, lowering significantly the cutoff frequency of the tweeter filter to around 5KHz, and using some notch filtering (paralel with the speakers) for uper side of mid's.
The main problem now are the impedance of speakers that become to low between 800Hz and 5KHz. The mean value of impedance is ~8.2Ω but in this range the lower peak it is around 3Ω.
The measured distorsions are resonable low with a narrow peak at ~5KHz were are double compared to the rest of the band.
For the moment I will stay like this and listen to see if it is need to be changed or not.
To increase the impedance for mid range I tried with notch in series with the mid speaker but the results was not so nice to my ears. Maybe you have some idea how to increase the impedance for this mid band.
Thank you.
Most of the impedance issue you have is likely to be the two mids, in parallel. Switching to a single mid would help. But it could also be the multiple notches. Try a single mid, and see what Z does in response.
Of course, you will need to halve/double the L/C to keep the filter slopes and notches. Notch R will need fixing too.
Of course, you will need to halve/double the L/C to keep the filter slopes and notches. Notch R will need fixing too.
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Ah...well if they're in series then it is the notch. Is your notch a parallel tank, running in series with the mid? If so i would try a series LCR, shunting the mids. But you tried that. I'm not sure how well that would work anyway, with series connected mids....
That only leaves TVRs suggestion: lower the crossover to the tweeter at a much lower point, say 2-3k. The mids will sound less directional anyway, and its probably the best idea.
That only leaves TVRs suggestion: lower the crossover to the tweeter at a much lower point, say 2-3k. The mids will sound less directional anyway, and its probably the best idea.
Is the crossover a generic one or it was "in bundle" with the speakers, or projectd by you?
In the last case, hats off, but...
It uses some industrial parts rather than "audiophile parts"; I'd prefer a single big cap instead of the multi-arrangement; the two Rifa back-to-back might be okay; the three aligned inductors are no good: the one in the center should be rotated by 90°
In the last case, hats off, but...
It uses some industrial parts rather than "audiophile parts"; I'd prefer a single big cap instead of the multi-arrangement; the two Rifa back-to-back might be okay; the three aligned inductors are no good: the one in the center should be rotated by 90°
Hi picowallspeaker,
I was made from zero by me. Is not the perfect one because was difficult with speaker not from top quality but it sound ok now.
Regarding single big cap instead of the multi-arrangement, I'm agree but was in my pocket and to buy 100µ quality capacitor are not so cheap.
Regarding big coils, you're right and I will change next time when I will open the speakers, but anyway mutual influences are not so big because are with close magnetic circuit.
I was made from zero by me. Is not the perfect one because was difficult with speaker not from top quality but it sound ok now.
Regarding single big cap instead of the multi-arrangement, I'm agree but was in my pocket and to buy 100µ quality capacitor are not so cheap.
Regarding big coils, you're right and I will change next time when I will open the speakers, but anyway mutual influences are not so big because are with close magnetic circuit.
Some details...
I modified a little the filters comparing with the photos.
For bass I made a order two filter and two notch, one in parallel with the speaker at 70Hz and one in series with the speaker at 600Hz. The last one works like a contour or baffle step compensation also.
For midwoofers I use a order two filter and two notch, booth in parallel with the speakers, one at 360Hz and one at 2300Hz. Series on the input of this filter it is a "contour" inductor of 3.3mH in parallel with 5Ω.
And for tweeter I use a order three filter and one notch filter at 12Khz. The tweeter has a protection made with a bulb of 10W/12V halogen - 1.5Ω (with pins, was very easy to solder). Can be seen in right side of first photo (it is covered with a shrink black tube).
The minimum impedance it is 4.2Ω between 450-1600Hz and 4.8Ω below 80Hz. Seems to be generated by the notch's. The maximum impedances are 11Ω over 10KHz.
I modified a little the filters comparing with the photos.
For bass I made a order two filter and two notch, one in parallel with the speaker at 70Hz and one in series with the speaker at 600Hz. The last one works like a contour or baffle step compensation also.
For midwoofers I use a order two filter and two notch, booth in parallel with the speakers, one at 360Hz and one at 2300Hz. Series on the input of this filter it is a "contour" inductor of 3.3mH in parallel with 5Ω.
And for tweeter I use a order three filter and one notch filter at 12Khz. The tweeter has a protection made with a bulb of 10W/12V halogen - 1.5Ω (with pins, was very easy to solder). Can be seen in right side of first photo (it is covered with a shrink black tube).
The minimum impedance it is 4.2Ω between 450-1600Hz and 4.8Ω below 80Hz. Seems to be generated by the notch's. The maximum impedances are 11Ω over 10KHz.
Mmmhh..why are you keeping the Xo's inside the box ?
I'm looking at those SAL DTF 12 tweeters...they're said to be 50W-100W
I think that you already know that the real wattage is around 10 W !
Anyway it's not a problem as tweeters in a 3 way system should perform over 5 kHz. So what do you use below that frequency ?
I've talked about double coil drivers...so the only economical thing is the Monacor SPH-135TC, which is the littlest with the TC feature.
I'm looking at those SAL DTF 12 tweeters...they're said to be 50W-100W
I think that you already know that the real wattage is around 10 W !
Anyway it's not a problem as tweeters in a 3 way system should perform over 5 kHz. So what do you use below that frequency ?
I've talked about double coil drivers...so the only economical thing is the Monacor SPH-135TC, which is the littlest with the TC feature.
Whoops!
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Hi picowallspeaker,
I do not know what you mean.
Regarding tweeter, Of course, I know that the power it is only 8-12w but for a 100W-150W speaker I do not need more than 10-15W.
You mean to use over or under 5KHz?
I do not know what you mean.
Regarding tweeter, Of course, I know that the power it is only 8-12w but for a 100W-150W speaker I do not need more than 10-15W.
You mean to use over or under 5KHz?
I don't know where the double midwf arrangement comes from... maybe it's due to the fact that a designer first establishes that the woofer's gonna be huge so high Sd and high sensitivity ( depends on the positioning ) so to match the Spl a double driver is chosen 
But in series arrangement
there's no change in Spl since they share total voltage and each gets 1/2.
Oh! But this project has a side firing woofer. But I wouldn't let the midrange
to be diffused by two drivers=two voices. Actually, now I'm listening with a 4" woofer, 3" mid and 1 " tweeter. Pmax=5 W and the crossover is external: why ? Because 1st: you can change whenever/whatever you want; 2nd you don't need any binding posts; 3rd and much important the parts stay away from the influence of the vibrations; indeed to perform optimally each part should be isolated mechanically from the other but this implies a re-design from the roots
But in series arrangementthere's no change in Spl since they share total voltage and each gets 1/2.
Oh! But this project has a side firing woofer. But I wouldn't let the midrange
to be diffused by two drivers=two voices. Actually, now I'm listening with a 4" woofer, 3" mid and 1 " tweeter. Pmax=5 W
and the crossover is external: why ? Because 1st: you can change whenever/whatever you want; 2nd you don't need any binding posts; 3rd and much important the parts stay away from the influence of the vibrations; indeed to perform optimally each part should be isolated mechanically from the other but this implies a re-design from the roots
Hi picowallspeaker,
The mid's are 4Ω and the rest of speakers are 8Ω.
Originally the mid's was without high pass filter, was only cut in high region to limit the breakup of the cone.
BTW the mid's are with plastic cone, and the woofer was without any filter, connected to a second pairs of connectors for biamping "maybe" ...
I transformed the speakers from 2 way + subwoofer to 3 way. Because of this the mid's are cut very low, under 200Hz (~80-100Hz) and I tray to fill the gap in response of woofer.
I post a measurement of woofer, maybe you have a clue why I have the peak at ~90Hz or more precise, why is the big gap between 100Hz and 180Hz? The box are vented but I filled the port to transform in close box. The woofer are not marked so I do not have any datasheets for it.
The mid's are 4Ω and the rest of speakers are 8Ω.
Originally the mid's was without high pass filter, was only cut in high region to limit the breakup of the cone.
BTW the mid's are with plastic cone, and the woofer was without any filter, connected to a second pairs of connectors for biamping "maybe" ...
I transformed the speakers from 2 way + subwoofer to 3 way. Because of this the mid's are cut very low, under 200Hz (~80-100Hz) and I tray to fill the gap in response of woofer.
I post a measurement of woofer, maybe you have a clue why I have the peak at ~90Hz or more precise, why is the big gap between 100Hz and 180Hz? The box are vented but I filled the port to transform in close box. The woofer are not marked so I do not have any datasheets for it.
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