Oh, wow!
I am not even there yet. Wonder what I'll cook up as a mid life crisis build?
Do you think double 21" per channel will be enough? :-D
I completely agree on starting with a good 15" per side Chris. It saves a bit of time and effort skipping a couple of steps.
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I like the enthusiasm! Crossing a 15" to a compression horn scares me but the simulation doesn't look too bad. The 15" starts to beam at 600Hz.
There will be more projects. I think this one should be a 3-way and I am considering dual 12" since the cabinet may need to be at least that wide to help with crossing the mid down low.
Driver total as mentioned is around $1k. This is a good target.
Why did you choose SB26STCN-4 over SB29RDC-C000-4? I can always cut a hole for the larger tweeter and 3D print new face plates for smaller versions. For that matter, I may be designing a new faceplate already to get the mid/tweeter closer together.
I agree the Zmin won't be an issue for my amps or really any that I'd seriously consider for bass. These will be bi-amp'able if needed.
I'm curious what you used to model the speaker?
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Xmax for the WO24P-8 is only 8.5mm. SB is giving its driver excursion stats as peak to peak so you have to divide by 2 to arrive at xmax.
There is no replacement for simulations when comparing woofers. Attached is a comparison of 5 single woofers in their standard tunings all at their xmax limits above a minimum of about 25Hz (it'll vary with each driver's F3).
Perhaps obviously, the clear winners for max SPL are the SB29NRX and the SB34NRX, by 6dB over the RS225. The Satori WO24 has pretty much the same max SPL as the RS225-8, though it digs a little deeper, and the SB23NAC (which I would probably prefer over the 23NRXS for its stiffer cone) actually cannot play as loud as the RS225, by 2dB.
Note that the larger 10" and 12" woofers can play louder if you elect to tune them higher, the higher tuning obviously requiring less excursion, but the SB34 in particular wants a very large vented box to start off with. Going sealed on that one might be the better choice but it's still asking for 100L per driver. And you don't get the extra SPL headroom sealed as you do with a port assisted higher tuned vented alignment.
Calculations were all done in Unibox.
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Satori WO24P-8 is woefully under sized. I mistakenly read the excursion as 17mmp not p-p.
SB29NRX75-6 is the current leader at 11mm peak and 3" VC with 200W power handling. The lower impedance is a good match for my amps.
Here are the SBB4 and Sealed options. Actually, with room gain the sealed response could be adequate but SBB4 is well within my design constraints.
SB29NRX75-6 is the current leader at 11mm peak and 3" VC with 200W power handling. The lower impedance is a good match for my amps.
Here are the SBB4 and Sealed options. Actually, with room gain the sealed response could be adequate but SBB4 is well within my design constraints.
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What does the flat part of the curve represent? The RS228 has a maximum SPL at max rated power of about 105dB, the SB34NRXL (designed for a normal sized ported cabinet unlike the SB34NRX) about 114 dB and the SB29RNX about 110dB.
Penny drops (well perhaps) the port resonance is tuned so low that it is not adding sufficiently to the cone motion over a range of frequencies above the port resonance where it is hitting xmax before max power. The signal is then reduced for all frequencies so as not to exceed this xmax limit? But hitting xmax before max power below the port resonance is ignored?
Seems an odd way of looking at things and may explain the OPs comment about tuning earlier. Can you please add the curve for SB34RNXL which doesn't have this hole and should hopefully show 114 dB or so? (well if I have understood the plot).
Ported boxes have limited output (some would say none) below port tuning.
Luckily I have the option to high pass in DSP and probably will because I have seen LFE special effects content below 10Hz sneak by other systems. I plan to use these speakers for music (80% of time) and movies (20% of time). Of course if i hear "bad sounds" I'll back off, but that isn't the best plan.
andy,
In my experience, most drivers' xmax is exceeded before max power, but it totally depends on the LF you are asking them to reproduce. For music where most content is above 30Hz, I'm not concerned if xmax is exceeded at 25Hz but for movies it would be a different story. Throw a HP filter on them and excursion requirements are much diminished and it's a different story again and now I'll want to know how much power I can actually throw at it.
Unibox has an excellent graph on its 2nd tab which displays max SPL at every frequency before xmax is exceeded. So below are:
1 & 2. SB34 in 245L tuned to 19Hz - Unibox says max SPL is 111dB (which is lower than I would expect but I'm not going to quibble about that for my purposes here) and the red line shows that xmax will be exceeded anywhere below about 47Hz in this alignment with this amount of power. The 2nd graph shows the same thing but just in terms of xmax.
3 & 4. SB34 now in 40L tuned to 20Hz again with 200W - so an alignment that allows max power without exceeding xmax above about 15Hz (not that I'd actually want to tune it like this though).
5. SB34 comparison:
- blue is in 245L tuned to 19Hz with 65W and xmax is not exceeded (this is what I posted previously)
- pink is with max power of 200W in the same 245L box and tuning
- black is in 40L box tuned to 20Hz with F3 up to 39Hz but without xmax exceeded above 15Hz at 200W
Does that answer your question?
In my experience, most drivers' xmax is exceeded before max power, but it totally depends on the LF you are asking them to reproduce. For music where most content is above 30Hz, I'm not concerned if xmax is exceeded at 25Hz but for movies it would be a different story. Throw a HP filter on them and excursion requirements are much diminished and it's a different story again and now I'll want to know how much power I can actually throw at it.
Unibox has an excellent graph on its 2nd tab which displays max SPL at every frequency before xmax is exceeded. So below are:
1 & 2. SB34 in 245L tuned to 19Hz - Unibox says max SPL is 111dB (which is lower than I would expect but I'm not going to quibble about that for my purposes here) and the red line shows that xmax will be exceeded anywhere below about 47Hz in this alignment with this amount of power. The 2nd graph shows the same thing but just in terms of xmax.
3 & 4. SB34 now in 40L tuned to 20Hz again with 200W - so an alignment that allows max power without exceeding xmax above about 15Hz (not that I'd actually want to tune it like this though).
5. SB34 comparison:
- blue is in 245L tuned to 19Hz with 65W and xmax is not exceeded (this is what I posted previously)
- pink is with max power of 200W in the same 245L box and tuning
- black is in 40L box tuned to 20Hz with F3 up to 39Hz but without xmax exceeded above 15Hz at 200W
Does that answer your question?
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Thanks for the effort but not really. I would have liked to see the plots for the SB34RNXL not the SB34RNX. The former has suitable parameters for the OPs objectives whereas the latter does not. I have looked up the unibox software and it requires MS Excel and so I am unable to run it myself.
Regarding the hole in the max SPL due to too low a port tuning. I would agree it is common for home audio speakers but it is not for higher quality speakers like studio monitors. Lower SPL and higher distortion at musically important frequencies in exchange for an increased anechoic low frequency extension which is largely irrelevant in room is not a good deal if sound quality is important. Doubly so in the case of the OP who knows he wants to push the SPL.
Sorry andy, my mistake. I missed that you were looking at a different driver.
This is indeed better looking. Standard design calls for 58L tuned to 32Hz for an F3 of 36Hz. Doesn't go as low as the other SB34NRX, but it will handle all 200W max without exceeding xmax for content above about 25Hz. And max SPL is 114dB. Excellent choice even as a single driver for music but it doesn't really cut it for movies without a dedicated sub.
This is indeed better looking. Standard design calls for 58L tuned to 32Hz for an F3 of 36Hz. Doesn't go as low as the other SB34NRX, but it will handle all 200W max without exceeding xmax for content above about 25Hz. And max SPL is 114dB. Excellent choice even as a single driver for music but it doesn't really cut it for movies without a dedicated sub.
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Model of Avalon truncated pyramid used for simulation baffle data. The MR16P-4 has a modest Sd=118 cm^2 curvelinear cone with Mms=11.2g which supports a 2kHz BW3 crossover without beaming. A 26mm dome is a good match for a 2kHz BW3 crossover. The small NdFeB motor case size of the SB26STCN-4 allows a close C-to-C. Attached simulations of an Avalon cabinet (1" + 5.5" + 12") with the 12" SB34NRXL75 ported woofer with modest in-room placement -F3~34Hz.
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Except the midrange is wholly unsuitable for the OPs use as I and someone earlier tried to point out. We know the current 110 dB from the pair of RS225s is inadequate and the woofers need to produce 115 dB or 120 dB. Whatever it is, a midrange with 40W power handling will fail long before the SPLs the OP is looking for are reached. The midrange requires a bigger motor.
One thought based on the previous discussion. If the OP has tuned his current RS225s for a low F3 then they may actually be crapping out at 100 dB at frequencies where there is significant energy in the music and not 110 dB. This would rather change things.
Thanks for that which has helped me understand some odd plots I have seen in the past that I failed to clarify.
Right, sorry about that ( I got carried away at admiring < once again > another nice photo montage from LineSource in a DFM thread ).
I tend to agree, the OP should provide some box tuning info for his current under-performing RS225's .
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I'm not there, either (mid-20s at the mo). That said, my quarter-life-crisis (aka PA system that I run a business on) looks like this:
Anyway, sorry all for the OT.
I really do think a 15" 2-way (or 3-way, if you use one of those BMS coaxials) would be the way to do it. A high-power 15" per side would cheerfully annihilate the home HiFi drivers discussed so far.
Cheers,
Chris
FYI - My current speakers with dual RS225 speakers are in a 100L vented box tuned to 35Hz (measured). This ended up a bit higher than I wanted.
Also, I would consider a single 15" but I don't know if I could make them look as nice as dual 10" or 12". I know it's not that much larger but I've owned 15" woofers before and you can't hide the fact that they are huge. The PA cones are kind of ugly for home use as well. Sorry!
Also, I would consider a single 15" but I don't know if I could make them look as nice as dual 10" or 12". I know it's not that much larger but I've owned 15" woofers before and you can't hide the fact that they are huge. The PA cones are kind of ugly for home use as well. Sorry!
MR16P-4 can handle 40W IEC 268-5. I prefer to use EIA RS-426-B which would greatly decrease the midrange load compared to the woofer. I think it may be OK since I don't plan to run full out at >110dB SPL. This is HiFi however and if you have a better solution please let me know.
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