This project seems to always be under construction, don't you just hate that ? 
I started this project as a sealed two way, knowing that I will at some point add something (not exactly knowing what at that time) to take care of the bottom end. I picked scan speak 9500 tweeter, and vifa pl18wo mids. Using unibox, winisd and other people suggestions I went ahead with a sealed enclosure of about 18-20 liters, minus driver displacement and bracing. Without any measuring or crossover software I had to a) do another textbook crossover b) have someone simulate one c) try and combine crossover "branches" from other designs. I went with b) and then over time kept changing components. For the longest time this has been my main speaker, even though it didn't have much to offer in bass department. Simulated f3 is at around 80hz, without factoring in room gain. Lived with this for almost a year.
Finally I decided to give scan speak 25w/8565-01 a try. I put them in 60 liter minus bracing and driver displacement sealed cabinets hoping that I'll get enough bass for various musical genres. I stuffed the cabinets about 3/4 of the way with Acousta-Stuf from PE. Bass is very clean, musical, but not very deep. Projected f3 here is just under 40hz w/o room gain. With only about 60 watts per woofer I get more than enough bass even in a larger living room, with pretty much anything I throw at it. From jazz cuts to highly compressed yet synthetically clean techno and drum and bass sounds.
I bought a behringer cx3400 active crossover from guitar center so I could play with different crossover points. I kept my two way passive, and spliced the active crossover between the two way and the woofers. I tried everything from 44hz to about 350hz, and I settled on the 70hz area. Crossover was setup in 2way, so at the same time it was running a low-pass on the woofer, my two ways were going through a high-pass section. I am sure this woofer is more than capable of running higher, I just like how it sounds crossed fairly low.
What I need to try next is, run the two ways full range and lowpass the woofers. I want to hear the difference between a 2.5 way and 3way. I know this is not a perfect way to do this, and its way over simplified but I imagine that I most likely won't be able to play it just as loud with the 2.5 way compared to 3way.
I recently got some measurements done with some help of a local speaker builder (Thanks Mark!). Now its back to the drawing board again.
Question is, 2.5 way or a 3 way ? Tell me what you think, and your reasons
I started this project as a sealed two way, knowing that I will at some point add something (not exactly knowing what at that time) to take care of the bottom end. I picked scan speak 9500 tweeter, and vifa pl18wo mids. Using unibox, winisd and other people suggestions I went ahead with a sealed enclosure of about 18-20 liters, minus driver displacement and bracing. Without any measuring or crossover software I had to a) do another textbook crossover b) have someone simulate one c) try and combine crossover "branches" from other designs. I went with b) and then over time kept changing components. For the longest time this has been my main speaker, even though it didn't have much to offer in bass department. Simulated f3 is at around 80hz, without factoring in room gain. Lived with this for almost a year.
Finally I decided to give scan speak 25w/8565-01 a try. I put them in 60 liter minus bracing and driver displacement sealed cabinets hoping that I'll get enough bass for various musical genres. I stuffed the cabinets about 3/4 of the way with Acousta-Stuf from PE. Bass is very clean, musical, but not very deep. Projected f3 here is just under 40hz w/o room gain. With only about 60 watts per woofer I get more than enough bass even in a larger living room, with pretty much anything I throw at it. From jazz cuts to highly compressed yet synthetically clean techno and drum and bass sounds.
I bought a behringer cx3400 active crossover from guitar center so I could play with different crossover points. I kept my two way passive, and spliced the active crossover between the two way and the woofers. I tried everything from 44hz to about 350hz, and I settled on the 70hz area. Crossover was setup in 2way, so at the same time it was running a low-pass on the woofer, my two ways were going through a high-pass section. I am sure this woofer is more than capable of running higher, I just like how it sounds crossed fairly low.
What I need to try next is, run the two ways full range and lowpass the woofers. I want to hear the difference between a 2.5 way and 3way. I know this is not a perfect way to do this, and its way over simplified but I imagine that I most likely won't be able to play it just as loud with the 2.5 way compared to 3way.
I recently got some measurements done with some help of a local speaker builder (Thanks Mark!). Now its back to the drawing board again.
Question is, 2.5 way or a 3 way ? Tell me what you think, and your reasons
Passive two way xo graph -
All drivers measured w/o xo -
Last picture, subject in question 😉
An externally hosted image should be here but it was not working when we last tested it.
All drivers measured w/o xo -
An externally hosted image should be here but it was not working when we last tested it.
Last picture, subject in question 😉
An externally hosted image should be here but it was not working when we last tested it.
Hi Jean
Nice to see your project in action.
Just a few questions to clarify the info you've given:
The passive two way XO graph (in B&W) shows an F3 of over 100 Hz. These are you mains right?
The graph of the driver responses (colour) has me baffled. The green must be the woofer, the red the mid and the yellow the tweeter. Why does the woofer roll off so early in this graph, and why is the mid response so roller-coaster-like?
How are you crossing over to the woofers at 70 Hz, if your mains have already started rolling off above 100 Hz?
I don't know a lot about 2.5 ways, but if the mid-woofers in your mains don't go as low as your woofers, then you can't get an even response. You will get a significant boost in level where the mid-woofers start to come into their range (around 80 - 100 Hz and up). You would normally cut your woofers out at the frequency at which the baffle step comes into play, which in your case will be two points, because you have one baffle width for your woofer, and one for your mains.
Starts to get complicated. Sounds like a 3-way is best here.
Did you measure the response with the woofer and mains working together with your 80 Hz XO point?
Mick
Nice to see your project in action.
Just a few questions to clarify the info you've given:
The passive two way XO graph (in B&W) shows an F3 of over 100 Hz. These are you mains right?
The graph of the driver responses (colour) has me baffled. The green must be the woofer, the red the mid and the yellow the tweeter. Why does the woofer roll off so early in this graph, and why is the mid response so roller-coaster-like?
How are you crossing over to the woofers at 70 Hz, if your mains have already started rolling off above 100 Hz?
I don't know a lot about 2.5 ways, but if the mid-woofers in your mains don't go as low as your woofers, then you can't get an even response. You will get a significant boost in level where the mid-woofers start to come into their range (around 80 - 100 Hz and up). You would normally cut your woofers out at the frequency at which the baffle step comes into play, which in your case will be two points, because you have one baffle width for your woofer, and one for your mains.
Starts to get complicated. Sounds like a 3-way is best here.
Did you measure the response with the woofer and mains working together with your 80 Hz XO point?
Mick
Hello Mick,
Measurements were done outside on a tall stand, with a mic one meter away. Thats probably why f3 looks to be higher in the graph.
I don't have a passive 2.5 or 3 way crossover yet, only the TM section was measured at once with its passive xo.
Once I have a full working crossover I will get them measured again all at once in room this time, hopefully i'll be ok.
Jean.
Measurements were done outside on a tall stand, with a mic one meter away. Thats probably why f3 looks to be higher in the graph.
I don't have a passive 2.5 or 3 way crossover yet, only the TM section was measured at once with its passive xo.
Once I have a full working crossover I will get them measured again all at once in room this time, hopefully i'll be ok.
Jean.
From the chart it looks as if the measurement window was smaller than 8ms, right ?
If this is the case it is only natural that the MEASURED response drops off that high.
Short measurement windows and measurement of low frequencies are mutually exclusive.
If you want to measure low-end response you have to take long measurement windows, whereas you'll have to thake short ones to get rid of room reflections when measuring mid- and high- frequency response.
As ever: You can't always get what you want (life would be boring otherwise).
Regards
Charles
If this is the case it is only natural that the MEASURED response drops off that high.
Short measurement windows and measurement of low frequencies are mutually exclusive.
If you want to measure low-end response you have to take long measurement windows, whereas you'll have to thake short ones to get rid of room reflections when measuring mid- and high- frequency response.
As ever: You can't always get what you want (life would be boring otherwise).
Regards
Charles
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