I used the instructions here to get a simulated response from an image of the frequency response and impedance curves published by Mark Audio
https://www.diyaudio.com/community/threads/vituixcad.307910/post-7027808
The frequency curve from Mark Audio also shows a big bump around 10kHz. This data is on-axis only and the off-axis data is simulated using VituixCad.
I understand I am using published data and not measured data but given the fact that I build a speaker only about once a decade, don't own these drivers and don't have the equipment or infrastructure to conduct frequency measurement tests (in open air or an anechoically dead room) the best I could do was used published data.
The off axis response should exhibit a lower peak than on axis. The on axis peak is there because the nature of a full ranger, is it beams at higher frequencies. If the on axis treble response was flat, the off axis treble would be very low.
Something is off with the simulation, in other words.
Something is off with the simulation, in other words.
I thought the 3k dip looked a bit too perfect.
With regards to this higher frequency issue at least, you could do your own polar measurements.
Vituixcad might not correctly simulate the part you're interested in. Simulations become productive once you understand their limitations and strengths. You should have been informed of these.
With regards to this higher frequency issue at least, you could do your own polar measurements.
Fair enough.
What would you reckon I did wrong? I did some more simulations and found that there are several woofers that might work well (or at least they will all work equally well) with the MAOP 7.
Do these look any better?
My object with VituixCAD was only to determine which woofers if any will work well (or if there are several which would be the best choice) with the MAOP 7.
I currently have 4 candidates. All of them cost around $100-120 each.
SEAS L16RNX (1488)
SEAS U18RNX (1571)
SEAS U16RCY/P (1520)
SEAS L16RN-SL (1480)
I found that rolling the woofers off less steeply would give a better response on paper because the woofer's midrange response would fill the dip in the MAOP 7 on-axis response. However, given that the woofers are on the side walls of the cabinet I don't really like crossing them over too high. No simulation is going to simulate "side-mounted" woofers.
In my room, I have my speakers toed in towards the listening position as this is the most WAF option.
Which woofers to use? I'm not sure I see how vituixcad could help you find an answer to that? More or less all woofers will behave similarly when crossed low. (not talking about the obvious things like sensitivity) Also, different woofers can be forced to have the same response.
Thanks, Allen.
Sensitivity (between F-10 and say 500Hz) was the primary concern since the design calls for 4 woofers to match with a single MAOP 7.
The other parameter was the response in an 11-12 litre bass reflex box (MLTL is an extrapolation/variation of a bass reflex box)for example from the drivers listed above the SEAS L16RN-SL H1480 (used by Linkwitz) prefers a box (QB3 alignment) that is about 25-28 litres.
The other question was how fast should these side-firing woofers roll-off? How high can we cross them and at what slope? Given that there are 4 of them flanking the full range (above and below and on both sides) would the sound emanating from them envelop the full range and how does this affect the response of the system. If we can cross them higher and gentler maybe the U18RNX/P H1520 and U16RCY/P H1571 might work better since they do not have any serious peaks in the upper-frequency response.
I tried researching this but found very little info.
Thanks, Leif, I haven't tried simulating this woofer. Based on the published T/S it might need a box larger than 11-12 litres.
Simulating side woofers may be an interesting challenge. So I'd ask the question, 'can it be done'... because if it can then you can build it, then measure to find out where to cross.
Kef does it, and some say it will be less than perfect. I think that with your own polar measurements, vituixcad could help you find a way to cross them. This doesn't include your house curve equalisation or room set up.
Kef does it, and some say it will be less than perfect. I think that with your own polar measurements, vituixcad could help you find a way to cross them. This doesn't include your house curve equalisation or room set up.
I would assume Dave (planet 10) would know because he has actually designed the Tysen V2 which uses a pair of woofers (in MLTL) flanking a full range (MidTL).
The closest I can come is something like this:
Not a huge difference between these 2 (and several others) which is what confuses me.
If I was confident I would be ordering drivers and building. The challenge I have is to order drivers from 8000 miles through custom duties and taxes without knowing if they will work. It's a bit of a chicken and egg syndrome.
Thanks, Dave, for the confidence. I do eventually intend to go active (or PLL) using an integrated amplifier for the full range and a power amplifier for the bass. The integrated amplifier has both a "pre-out" which can be sent to a crossover and a "power in".
The driver I preferred (the SEAS L16RNX H1488) would have to be specially ordered for me by Madisound (3-4 month lead time). For some reason, no one seems to utilise this driver so Madisound rarely stocks more than 2. They do have adequate and regular stock of the L16RN-SL H1480. I suspect this is a special Sigfried Linkwitz version of the L16RNX H1488 for their LX series of speakers.
I ran simulations using both above in post #2091. I also ran simulations using 4 other 6-7" SEAS drivers (under $120 each) but prefer to use a metal cone since the MAOP 7 is also a metal cone and I believe the timber of an aluminium cone woofer would match the MAOP 7 better. The specifications of both the L16RNX and L16RN-SL are below.
https://www.madisoundspeakerstore.c...l16rnx-6-aluminum-cone-woofer-h1488-08-8-ohm/
https://www.madisoundspeakerstore.c...estige-l16rn-sl-h1480-5-aluminum-cone-woofer/
I am a little concerned about the L16RN-SL H1480 version since the Madisound recommendation is only for a sealed box (with its highish Qts of 0.46) and not for a vented box. Would this concern you?
Actually, I haven't. Don't remember why.
There are 3 that might work.
SB17NRX2C35-8
SB17CAC35-8
SB17CRC35-8
of these, the NRX and CAC look more promising.
Thanks.
