Yes, I am within the three octaves (it is not a law
)The only driver and horn that need to cover 3 octaves is Radian 850 with 200hz tractrix. The rest cover 1 or 2 octaves at most.
I have dsp and I have tried different frequency bands. I also tried 3 way and 4 way configurations.
Here is one thing I have to say. If you can have flat impedance and then filter with 6db crossovers, you have a very coherent and dynamic sound, without overlapping problems. Those areas that overlap actually complement each other and create a flat response. The time alignment becomes crucial too. You move drivers out of alignment and you start to have dips etc.
When you try 6db filters without impedance equalisation, you can not filter with 6db actually. Just do that and measure. You will see the result is different. The filters are too soft and you are working against impedance. So you need steeper filters to achieve the separation maybe for similar results. Steeper filters change the sound and the transient response for the worse for my ears. This is again maybe the result of my implementation. One may achieve better results than me with steeper filters rather than impedance eq and 6db.
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My experience tells me otherwise. You actually need at least 1 octave of overlap and you need the drivers to have flat responses on the overlapped regions. If you also have the impedance flat, then you filter 6db, they sum up very nicely.
I guess there are many different approaches to the same problem. Correct implementation is the key here. I don't think there is one solution.
Like you say you have tried passive, but how deep you got into it? In a month or so I will share photos of the whole 8 boards of my crossovers, and I am sure you will be surprised
If one sees them, one may think they are not 6db or transparent...Or, when I say I used dsp, how good I was trying to implement it? Which dsp I used, what converters, with what amps for each channel?
i understand your answer and realize the beaming problem with the bigger midrange horn but maybe a driver in place of the 475 radian like Celestion CDX1730 to cover that range (really great in that range) should sound better. I am a firm believer in not using a large format driver that high in spherical horns because of the breakup and narrow power distribution as the frequency rises.
I haven't heard the celestion, I will be on the lookout to listen to one. It is also a 1" cd like the 475be I have. I couldn't understand why you call 475 a large format driver and the cdx1730 not?
system finished at last
As of this weekend my crossovers have arrived. I need to thank hornFabrik for their great work and help me assisting when designing them.
This is just a first day setup and the room will be properly treated. I have also finished building all the necessary acoustic panels.
The sound, although has minor relative attenuation work, it is not even in the same league as my old system which was very very good. I will be taking a lot of measurements this week and share them with you.
These 4 boards are crossovers for one channel, so I have 8 boards in total. It is a first order filter.
As of this weekend my crossovers have arrived. I need to thank hornFabrik for their great work and help me assisting when designing them.
This is just a first day setup and the room will be properly treated. I have also finished building all the necessary acoustic panels.
The sound, although has minor relative attenuation work, it is not even in the same league as my old system which was very very good. I will be taking a lot of measurements this week and share them with you.
These 4 boards are crossovers for one channel, so I have 8 boards in total. It is a first order filter.
Attachments
Here is one when I connected everything for the first time. These are the first measurements without adjustments and room treatment.
You can seen alignments issues, minor relative attenuation issues, bass and room interaction problems... I am solving them one by one
Attachments
after alignment
This is taken after the first alignment of the horns from listening spot. The 200 hz tractrix came forward about 3cms relative to fostex. The 1400 hz jmlc came about half a cm and the bass horn about 6 cm forward. The system sounds best without angling the horns at all.
The next step is treating the room properly. The biggest problem is from the floor bounce of the bass horn. You see the 200hz peak, that is that. Also the back chamber of the basshorn will have more stuffing (helps around 600hz) and that peak will be tamed.
The 70hz peak is a combination of floor and sidewall bounce from the dual tad bass units. With more treatment to the wall and floor, that will be tamed a little more.
This is taken after the first alignment of the horns from listening spot. The 200 hz tractrix came forward about 3cms relative to fostex. The 1400 hz jmlc came about half a cm and the bass horn about 6 cm forward. The system sounds best without angling the horns at all.
The next step is treating the room properly. The biggest problem is from the floor bounce of the bass horn. You see the 200hz peak, that is that. Also the back chamber of the basshorn will have more stuffing (helps around 600hz) and that peak will be tamed.
The 70hz peak is a combination of floor and sidewall bounce from the dual tad bass units. With more treatment to the wall and floor, that will be tamed a little more.
Attachments
.........
You can seen alignments issues, minor relative attenuation issues, bass and room interaction problems... I am solving them one by one
Could you explain how you deduce alignment issues from the graph. Thanks.
SMathews
Yes, it is on hi site, built to the full size without comprimising. It has Eminence 4015LF in it. It is operated between 20hz to 40/50hz. On the spl graph in post #254, the tapped horn is off. Tomorrow is a Sunday and I will have time hopefully to work on some more and put some new measurements here.
I built it out of 24mm mdf and 30mm mdf for the driver mounting.
I built my tad units bass box front plates out of 30mm mdf and the rest from 24mm mdf too.
I built it out of 24mm mdf and 30mm mdf for the driver mounting.
I built my tad units bass box front plates out of 30mm mdf and the rest from 24mm mdf too.
Please, share your measurements. I have the same TH in 20-50Hz range, but not very happy with the measurements - too high peak at 30Hz. I have room mode at this freq, but not so huge.
tapped measurement
Here is my measurement. Tapped from 20hz to 60hz 3rd order Linkwitz-Riley crossed to dual Tad 1601b woofers.
Tapped is pretty flat from 20 to 60hz. However I use it with the mouth at top. You may try that to reduce floor reflections. Also keep it in phase with the rest of the speakers not to have bumps or dips because of their interaction..
Here is my measurement. Tapped from 20hz to 60hz 3rd order Linkwitz-Riley crossed to dual Tad 1601b woofers.
Tapped is pretty flat from 20 to 60hz. However I use it with the mouth at top. You may try that to reduce floor reflections. Also keep it in phase with the rest of the speakers not to have bumps or dips because of their interaction..
Attachments
- Status
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