Back again with a few more questions.
My two-way cabinet build is almost complete and I'm starting to think about taking the in-cabinet measurements I will be doing for my crossover design (using Xsim).
Unless recommended otherwise, I am intending to measure outdoors.
In front of the house, where I will set up the speakers, the ground (driveway) drops away steeply and the nearest obstacle in front of the speakers will be a paling fence approximately 30m (95') away. But I will still check the impulse response for any reflections that need to be gated.
I'll be using REW for measuring, with my UMIK-1 mic 1m away.
The two way system is a Dayton RS225-8 in a TL enclosure and a Vifa TC9FD18-08 above in a sealed enclosure (FAST system - no tweeter).
Unless recommended otherwise, I was going to take all measurements on the axis of the 3.5" mid/high Vifa - measure each separately, and combined for Z offset.
Questions :-
1. If measuring in-cabinet, I assume I don;t need to simulate the Baffle Step?
2. Should I worry about room gain?
3. While I'm at it, should I take some off-axis measurements? And if so, how do I include them into my Xover design? Do I average them before creating the FRD file?
4. Is there anything else I need to consider or add to the measurements?
My two-way cabinet build is almost complete and I'm starting to think about taking the in-cabinet measurements I will be doing for my crossover design (using Xsim).
Unless recommended otherwise, I am intending to measure outdoors.
In front of the house, where I will set up the speakers, the ground (driveway) drops away steeply and the nearest obstacle in front of the speakers will be a paling fence approximately 30m (95') away. But I will still check the impulse response for any reflections that need to be gated.
I'll be using REW for measuring, with my UMIK-1 mic 1m away.
The two way system is a Dayton RS225-8 in a TL enclosure and a Vifa TC9FD18-08 above in a sealed enclosure (FAST system - no tweeter).
Unless recommended otherwise, I was going to take all measurements on the axis of the 3.5" mid/high Vifa - measure each separately, and combined for Z offset.
Questions :-
1. If measuring in-cabinet, I assume I don;t need to simulate the Baffle Step?
2. Should I worry about room gain?
3. While I'm at it, should I take some off-axis measurements? And if so, how do I include them into my Xover design? Do I average them before creating the FRD file?
4. Is there anything else I need to consider or add to the measurements?
1. That's right.
2. No, just reflections.
3. Big topic. May I suggest you don't design with them unless you're ready to look into it first. However it doesn't hurt to take some anyway and put them into FRD files and have them aside. You can learn things about your design simply by studying these.
It is also interesting to design your crossover on a 20/30 degree measurement, because this is sometimes used as a substitute for multiple measurements.
2. No, just reflections.
3. Big topic. May I suggest you don't design with them unless you're ready to look into it first. However it doesn't hurt to take some anyway and put them into FRD files and have them aside. You can learn things about your design simply by studying these.
It is also interesting to design your crossover on a 20/30 degree measurement, because this is sometimes used as a substitute for multiple measurements.
Thanks Allen.
The only reason I was asking about off-axis measurements, was that these speakers are for casual listening in our living area - not for critical listening in the "sweet spot".
But if serious listening was happening, it would be nice to have a quality image/sound stage.
The only reason I was asking about off-axis measurements, was that these speakers are for casual listening in our living area - not for critical listening in the "sweet spot".
But if serious listening was happening, it would be nice to have a quality image/sound stage.
Depends on what software you use for the XOver modelling.
In VituixCad for example, you keep each off-axis response as a separate frd and load the whole batch into the program at once.
There is a guide to preparing your measurements either in the helpfile or on Kimmo's website, make sure you read & understand it before doing your measurements.
I don't use XSim, so couldn't advise you on that.
Thanks Dave
VituixCad sounds like a great all-in-one program, but I haven't done any design for nearly 30 years (used a DOS version of Calsod!!!).
The general consensus of opinion is that Xsim is easier to learn, so I've been playing with Xsim while I've been building the enclosure.
In spite of being "easier to learn", I'm still struggling, so I think VituixCad is beyond my aging capabilities, even though I came from an engineering background.
Regarding off-axis responses, I just thought they were included as part of a standard crossover design.
Also, hopefully, this is a one-off project, so although I want to end up with good sounding speakers, I don't want to spend forever learning how to actually do the design.😉
VituixCad sounds like a great all-in-one program, but I haven't done any design for nearly 30 years (used a DOS version of Calsod!!!).
The general consensus of opinion is that Xsim is easier to learn, so I've been playing with Xsim while I've been building the enclosure.
In spite of being "easier to learn", I'm still struggling, so I think VituixCad is beyond my aging capabilities, even though I came from an engineering background.
Regarding off-axis responses, I just thought they were included as part of a standard crossover design.
Also, hopefully, this is a one-off project, so although I want to end up with good sounding speakers, I don't want to spend forever learning how to actually do the design.😉
A lot of datasheet also don't contain responses that are measured in infinite baffle, or just on some kind of infinite baffle but not quite. Some are even near-field. Just always look at the description
Using those kind of graphs can be useful to kind of globally determine some ideas.
But in general measurements are always needed.
Regarding the room, it's just a normal untreated open living room - 6.2m(20') x 5.5m(18') x 2.4m(8') - concrete floor, plasterboard walls, flat plasterboard ceiling
I'm only using the factory files while I'm learning to use Xsim.
Once my enclosures are built, I'll be taking my own outdoor meaurements.
They will probably need smoothing, but I now believe that Xsim will automaticaly apply 1/12 smoothing to the FRD files.