Hi,
The same speaker for 7 channels doesn't make much sense.
This for L, R and C makes sense : Zaph|Audio - ZDT3.5
And a simpler 6.5"/1" for the 4 surrounds, lots of choices.
rgds, sreten.
You wouldn't mismatch left and right so why mismatch front and rear, I want them all to match precisely.
In Boxsim, what line should be flat, total amplitude or energy frequency response? The total amplitude line slopes up.
In Boxsim, what line should be flat, total amplitude or energy frequency response? The total amplitude line slopes up.
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If you are seeking to maximise sound quality for a given amount of money then you would have better speakers for left and right, possibly centre, and lesser speakers for sides and rear which carry mainly indirect sound. If sound quality is not a significant concern, as would seem to be the case given the choice of drivers, then having all speakers the same might be the way to go.
Hi,
Matching precisely is precisely wrong, on lots of levels.
See the ZDT3.5 for a different (sealed) centre.
Also see : Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
4 rear channel speakers in 7.1 will barely put out more
volume than 2 rear speakers in 5.1, and those 2 in 5.1
do not handle the same levels as the L+C+R's.
Broad spectral matching in position is far more important
than so called identical speaker "timbre" matching. The
rear channels positioning is often more compromised
regarding near wall, and as such requires a different
approach. 7 identical speakers is no optimisation.
FWIW for a 7.1 amplifier its a good idea for LCR to
be 4 ohms nominal and the 4 surrounds to be 8 ohm.
rgds, sreten.
Sreten. Zaph, in the link you provided says it would be better if they were matched. He made the unique centre channel so it could fit under a TV.
I'm a little confused on where this thread is going, it seems that you're wanting to rush ahead and get things finished asap, but this can (will) result in massive problems.
On the presumption you're in the UK, where are you sourcing your drivers from?
I like your choice of drivers for a 3-way, there's a lot of sense to it.
Do you have a cabinet design in mind already or what's the deal? Will they be wall mounted/countersunk?
As you seem set on doing this fast and getting good results I could only recommend you get the drivers and cabinets done, get actual measurements for phase/impedance/FR and import them into a more suitable program such as box sim to get a better idea of of-axis response. There's no point making a speaker with a perfect flat on axis response if the off axis is all over the place, using real world measurements and a decent simulation package may cost a little at first (not much) but the final results will be well worth it as crossover defines so much of how a loudspeaker sounds - with that combination of drivers you should be able to achieve something very good, but could easily make a set of duds by accident.
On the presumption you're in the UK, where are you sourcing your drivers from?
I like your choice of drivers for a 3-way, there's a lot of sense to it.
Do you have a cabinet design in mind already or what's the deal? Will they be wall mounted/countersunk?
As you seem set on doing this fast and getting good results I could only recommend you get the drivers and cabinets done, get actual measurements for phase/impedance/FR and import them into a more suitable program such as box sim to get a better idea of of-axis response. There's no point making a speaker with a perfect flat on axis response if the off axis is all over the place, using real world measurements and a decent simulation package may cost a little at first (not much) but the final results will be well worth it as crossover defines so much of how a loudspeaker sounds - with that combination of drivers you should be able to achieve something very good, but could easily make a set of duds by accident.
Hi,
He doesn't say that at all as you imply, consistently.
The point of the centre is that its not the same as
as the L+R MTM's, depending on the actual usage.
He consistently states overall matching rather than
being identical matters. Hence the matching options.
rgds, sreten.
Sorry if it seems I'm all over the place, I'm not rushing, I would love to make 3 ways but its just too expensive now I know how much the crossovers will cost and I want them to be identical thats just me.
I am in the UK but I really like the Dayton reference series, all but center will be wall mounted.
I am in the UK but I really like the Dayton reference series, all but center will be wall mounted.
In the UK Dayton speakers are significantly more expensive than in the US and are usually out of stock. Your RS225-8 for example is currently a 60 day wait and is priced at $112.80 each whereas in the US it is priced at $57.42 each or $54.47 for 4+. They are not a high value choice here like they are in the US.
An 8" metal woofer is generally not suitable for use in a 2 way. At higher sound levels you will hear the cone resonating and, assuming the tweeter is crossed too low, distortion from the tweeter as well. All this will be in the frequency range where the ear is most sensitive. Here is an example thread of someone like you trying to use your combination of drivers and probably not succeeding.
Perhaps I should not bang on and just let you discover your mistakes yourself. I would recommend building a test pair first before purchasing the remaining five if you opt for a design that uses drivers outside their normal operating range.
Andy, that thread is from 2005 the drivers have been revised and I dont intend on making the same mistake as that idiot, I'm modelling it properly and using a sharper crossover at about 1.6K as the RS225 breaks up around 2K and this is within spec of the RS28F.
If you can find a driver just like the RS225 made in Britain I'd love to see it.
I'm going to make 1 first and test the drivers my self.
If you can find a driver just like the RS225 made in Britain I'd love to see it.
I'm going to make 1 first and test the drivers my self.
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The OP in the thread is new to designing speakers and just like you did not understand why 2 ways do not use 8" metal woofers. There is a broken link to a design that uses 8th order slopes and crosses at 1.4k using cherry picked tweeters in an effort to get the combination to work. This is too low for a 1" tweeter on a flat baffle without a waveguide and I am pretty confident it will sound poor at highish SPLs. I suspect the design was taken on by Mark K more in the spirit of seeing if it could be done rather than in an effort to create a good design. We would probably know more if his web site wasn't down.
If you are making an 8" 2 way rather than your original 8" 3 way then you do not want a driver like the RS225 which has been designed to be used as a woofer in 3 way with about 800 Hz being the maximum reasonable crossover point using normal passive crossover slopes. You want a driver that can be crossed at 2 kHz without problems and that requires a softer paper or poly cone. Volt is British and makes one but it is expensive. SEAS is Norwegian and makes both a paper and a poly 8" driver around the price of the Dayton that would work as midwoofers. Peerless (was Danish now manufactured in China) also makes an 8" that would probably work as midwoofer around the price of the Dayton. There are probably one or two more but not many.
8" 2 ways are relatively uncommon which is why there are few suitable DIY drivers around but drop to a 6.5" diameter and there is a large choice.
Hi Lake,
choose one of the: acoustic waveguides
together with your tweeter and you might
get away with a 2 way of your choice.
choose one of the: acoustic waveguides
together with your tweeter and you might
get away with a 2 way of your choice.
What do I set the "position of point of sound origin (SEO) to which phase response corresponds" to in Boxsim?
I'm simulating the original 3 way btw.
I'm simulating the original 3 way btw.
Commanderlake, you do seem to be floundering with this. I am amazed you are even thinking you can pull it off. 🙂
Let's look at a Visaton 3-way kit, the Casablanca IV.
and Visaton's description of the project.
An 8" metal bass is about what you are interested in. That Visaton project looks OK. I would set it up in Boxsim with appropriate cabinet, bass loading and add the recessed tweeter and mid time alignment to the point of sound origin. Looks a bit bassy IMO, but whatever. Crossing the bass at 750Hz should make metal 5kHz breakup easy enough to handle.
I always think you need an established point of departure with a design. Something that basically works. Then fiddle with it where you think you can improve it.
Let's look at a Visaton 3-way kit, the Casablanca IV.
and Visaton's description of the project.
An 8" metal bass is about what you are interested in. That Visaton project looks OK. I would set it up in Boxsim with appropriate cabinet, bass loading and add the recessed tweeter and mid time alignment to the point of sound origin. Looks a bit bassy IMO, but whatever. Crossing the bass at 750Hz should make metal 5kHz breakup easy enough to handle.
I always think you need an established point of departure with a design. Something that basically works. Then fiddle with it where you think you can improve it.
Do want me to go back to the 3 way layout or not? I just need to know what the SEO needs to be so I can simulate it.
That is up to you. An 8" 2 way would be more unusual and interesting particularly if you used a waveguide.
Assuming this is the acoustic offset then it is usually found by measuring it with a microphone. If you are using common pairings of drivers (woofer/midrange and midrange/tweeter) on a flat baffle then the offsets are likely to be mentioned in forum discussions or write-ups. However, I would still recommend checking with measurements on the baffle.
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