As my first real attempt at entering the fray regarding speaker building Im looking to build a speaker based on the monacor Aspera mk2 with the following spec for those who are unfamiliar:
http://www.eluxson.se/hogtalarbyggsatser/aspera-mk2.pdf
As per the plans the speaker requires 2 sph130's (https://www.monacor.com/en-gb/monac...nology/hi-fi-midrange-speakers/sph-130/?r=pdf) in an MTM arrangement with the dt250 tweeter, but what I would really like to know is would this system be capable of performing similarly if I were to use the same crossover arrangement as shown in the PDF above, but swap out either one or both the sph130 for it's bigger brother the sph175( https://www.monacor.com/en-gb/monac...nology/hi-fi-midrange-speakers/sph-175/?r=pdf ). Ideally I would really like to use the sph175's as I already have a pair of these available to use and hopefully keep costs a bit lower.
I understand that modifications will have to be made to box dimensions to facilitate this but I'm more concerned initially with the crossover and the effect of using 1 larger driver in MTM arrangement? Would i be able to turn it into a 2.5 way by introducing a lpf to the sph175 possibly?
Any advice would be greatly appreciated
http://www.eluxson.se/hogtalarbyggsatser/aspera-mk2.pdf
As per the plans the speaker requires 2 sph130's (https://www.monacor.com/en-gb/monac...nology/hi-fi-midrange-speakers/sph-130/?r=pdf) in an MTM arrangement with the dt250 tweeter, but what I would really like to know is would this system be capable of performing similarly if I were to use the same crossover arrangement as shown in the PDF above, but swap out either one or both the sph130 for it's bigger brother the sph175( https://www.monacor.com/en-gb/monac...nology/hi-fi-midrange-speakers/sph-175/?r=pdf ). Ideally I would really like to use the sph175's as I already have a pair of these available to use and hopefully keep costs a bit lower.
I understand that modifications will have to be made to box dimensions to facilitate this but I'm more concerned initially with the crossover and the effect of using 1 larger driver in MTM arrangement? Would i be able to turn it into a 2.5 way by introducing a lpf to the sph175 possibly?
Any advice would be greatly appreciated
Best to read the forum threads covering loudspeaker design simulations and the accompanying techniques of equalizing responses. Once you have the FR and IMP graphs of the drivers in a cabinet, you will be a lot smarter and then you could test it with aspera XO filter. This is what speaker design is about. TS parameters of the units will show whether cabinet should be closed or vented, along with internal volume.
1. setup a measurement system that works flawlessly
2. measure TS parameters of the woofer units to be able to define a cabinet
3. measure far field woofer and tweeter response in the intended box with a time window large enough to get meaningful data at lower frequencies.
4. measure impedance of the woofers in a cabinet, and tweeter also (enclosed tweeters could be measured outside)
5. import response data to a simulator for experimenting with filters
1. setup a measurement system that works flawlessly
2. measure TS parameters of the woofer units to be able to define a cabinet
3. measure far field woofer and tweeter response in the intended box with a time window large enough to get meaningful data at lower frequencies.
4. measure impedance of the woofers in a cabinet, and tweeter also (enclosed tweeters could be measured outside)
5. import response data to a simulator for experimenting with filters
Thanks for the advice I'll admit I'm certainly not an expert on the subject which is why I wanted to stick fairly closely to an existing design, but I have a very basic knowledge of the principles involved.
I tried to use a simulation in boxism based on the manufacturers supplied IMP and FR graphs and t/s parameters (not ideal, but as the majority of the speaker is based on a tried and tested design I was hoping I could still make it work? And to be fair I don't personally have the inclination or resources to setup a measuring system for a one off project)
I used software to trace the graphs but I'm sure that the data didn't import correctly as they definitely looked a bit all over the place in comparison to the originals I think due to too many points. I was hoping that as far as crossover the original design would suffice due to the similarity of the drivers (albeit slightly larger).
I tried to use a simulation in boxism based on the manufacturers supplied IMP and FR graphs and t/s parameters (not ideal, but as the majority of the speaker is based on a tried and tested design I was hoping I could still make it work? And to be fair I don't personally have the inclination or resources to setup a measuring system for a one off project)
I used software to trace the graphs but I'm sure that the data didn't import correctly as they definitely looked a bit all over the place in comparison to the originals I think due to too many points. I was hoping that as far as crossover the original design would suffice due to the similarity of the drivers (albeit slightly larger).
Load your files to Excel spreadsheet Response Modeler and adjust baffle step and other changes to impedance and then get XSim to simulate XO filters. That will be just the right thing for you and fast. If in a need of help, ask.
Ok I'll give that a go when I have a chance and see how I get on. I'm thinking now to maybe replace both drivers with sph175's as the graph for the finished aspera mk2 shows a dip in the fr (between 1-2k) that based on the graphs supplied by manufacturers the sph175 (which appears to have a peak along the same range and obviously should go a bit lower) will hopefully fill, please correct me if I'm looking at this from too simple of a view point?
Thanks for the advice, it definitely looks like I'm going to have to bite the bullet and delve a bit deeper if I want to try and get the best out of this 1st attempt at a diy speaker!
Thanks for the advice, it definitely looks like I'm going to have to bite the bullet and delve a bit deeper if I want to try and get the best out of this 1st attempt at a diy speaker!
If I were you I'd exchange for the sph175's right away and optimize the filter at a later time and in the mean time evaluate as it is. No big deal.
Yes, you are looking at an incomplete picture and perspective. To just change one driver isn't a good idea. It would still be limited by the smaller driver or you'd have to go for a 3-way. But then you'd be better off with a smaller mid driver (i.e. the excellent MSH-115). But swapping for two bigger bass drivers isn't that simple either.
Firstly, you've probably selected the Aspera because of the desctription of the sound. Well, the excellent wide radiation pattern will change a lot with a bigger bass. Not only narrows it down horizontally below the crossover frequency, the vertical pattern changes aswell because of the increased distance between the drivers. That said, the 'reproduced stage' of the speaker will differ a lot. While I'm all for dynamics, smaller drivers DO have certain advantages.
Secondly, a dip is much better than a peak, especally if it's very narrow, you usually can't hear it while a peak (even only small ones) can be very nasty. I don't know how the dip looks but you don't look to develop a speaker just on-axis. If it disappears off-axis, it's most likely better to keep it that way or you'll get a very audible peak there which throws off the tonal balance, also on-axis because you are hearing the reflections aswell.
A bigger bass changes the width of the baffle, so besides a different response and impedance of the bass driver, the baffle-step occurs at a lower frequency. That means, like Lojzek already said, you have definitely to modify the crossover, most likely you have to develop it completely new from scratch. That means, the speaker doesn't have anything to do with the original.
- Status
- Not open for further replies.