Hello everyone,
I purchased the SB Acoustics ARA from madisound about half a year ago and have been wondering if it's possible to upgrade these further without buying new speakers.
https://www.madisoundspeakerstore.c...ra-2-way-speaker-kit-pair-with-cabinets-2694/
Currently they use the MW16P-4 woofers (https://www.madisoundspeakerstore.c...w16p-4-black-egyptian-reed-cone-woofer-4-ohm/) and was wondering if I could possibly swap those with the new MW16TX-4 woofers (https://www.madisoundspeakerstore.c...satori-6-mw16tx-4-textreme-cone-woofer-4-ohm/) without messing with the crossover. I have the BE tweeters so the crossover was designed with a 2300 hz crossover I believe. I'm not too familiar with the crossover so I didn't want to mess with that too much.
I've seen an audio store online sell a configuration with the TX woofers but they also say they changed the crossover without much detail as to what changed.
I'm probably simplifying it too much to hope that I can just swap the woofer but just wanted to get a second opinion.
Appreciate any responses. Thanks!
I purchased the SB Acoustics ARA from madisound about half a year ago and have been wondering if it's possible to upgrade these further without buying new speakers.
https://www.madisoundspeakerstore.c...ra-2-way-speaker-kit-pair-with-cabinets-2694/
Currently they use the MW16P-4 woofers (https://www.madisoundspeakerstore.c...w16p-4-black-egyptian-reed-cone-woofer-4-ohm/) and was wondering if I could possibly swap those with the new MW16TX-4 woofers (https://www.madisoundspeakerstore.c...satori-6-mw16tx-4-textreme-cone-woofer-4-ohm/) without messing with the crossover. I have the BE tweeters so the crossover was designed with a 2300 hz crossover I believe. I'm not too familiar with the crossover so I didn't want to mess with that too much.
I've seen an audio store online sell a configuration with the TX woofers but they also say they changed the crossover without much detail as to what changed.
I'm probably simplifying it too much to hope that I can just swap the woofer but just wanted to get a second opinion.
Appreciate any responses. Thanks!
What would be your goal? Put otherwise, what is it you are missing now? Exchanging drivers in kits at this level requires adjustment of the crossover, or at least a thorough check on the acoustic transfer function.
In a perfect world it deserves some modelling and measurements to answer the question.
But, they are not to dissimilar in terms of impedance or level, but with differing Break up modes.
Whether the existing crossover adequately controls the roll off frequency and break up to give you the performance of the original design, and its integration with the tweeter only modelling and measurements can show.
If you can use Xsim or Vituixcad you can take the data from the links you provided, plus your tweeter data and compare both reed cone or texteme responses.
I think they will be very close and may only need a small adjustment. I would expect a subtle improvement over the already good reed cone, and probably a much safer bet than buying expensive capacitors etc. What is the main reason making you think about an upgrade?
Maybe a chat with Madisound will be useful, you never know Sb acoustics may update the design themselves just to demonstrate the texteme qualities.
But, they are not to dissimilar in terms of impedance or level, but with differing Break up modes.
Whether the existing crossover adequately controls the roll off frequency and break up to give you the performance of the original design, and its integration with the tweeter only modelling and measurements can show.
If you can use Xsim or Vituixcad you can take the data from the links you provided, plus your tweeter data and compare both reed cone or texteme responses.
I think they will be very close and may only need a small adjustment. I would expect a subtle improvement over the already good reed cone, and probably a much safer bet than buying expensive capacitors etc. What is the main reason making you think about an upgrade?
Maybe a chat with Madisound will be useful, you never know Sb acoustics may update the design themselves just to demonstrate the texteme qualities.
I'm mostly curious if I can bring the speakers up another level. I compared against another speaker with a lower tier driver and was impressed on how well the ARAs compared when it came to details and refinement.
Unfortunately I don't really have any software to use to compare. That's a good idea though. I'll see if Madisound has any color as to whether or not I can replace them.
Thanks for your responses. I'm guessing it's probably not possible but thought it wouldn't hurt to get some more opinions.
Though about the Rinjani maybe this would be of interest, USXX is the designer of the drivers and he is on diyaudio too I believe
http://forum.speakerbuilder.dk/forum_posts.asp?TID=2027&title=sb-acoustics-rinjani-be
Translate with Chrome or something.
I have the be & tx in a cabinet equivalent to the Ara, but I'm using an active crossover and eq and have never heard the mw16p
http://forum.speakerbuilder.dk/forum_posts.asp?TID=2027&title=sb-acoustics-rinjani-be
Translate with Chrome or something.
I have the be & tx in a cabinet equivalent to the Ara, but I'm using an active crossover and eq and have never heard the mw16p
Sorry, I didn't see this post until now. I designed a dedicated crossover for the ARA-TX. This is a different crossover configuration compared to the other ARA models. It brings out the best in these drivers (dynamics and transparency). I built external crossovers for these speakers (it was a little difficult to fit everything inside the cabinet, though it is doable if you split it on two boards). You can also find the schematic on SB Acoustics website under Open Source Kits. I'm not going to elaborate on the design here.
Attachments
Yes! This is not unusual with 1st order networks. One equalizes the single break-up (peak) above the crossover point, one shapes the upper roll-off (and corrects the phase) in the crossover region, and one deals with the baffle-step. This ensures a neutral balance, excellent integration with the tweeter and no residual energy that would otherwise cause a little bit of coloration.
I am thinking of building this speaker and found no frequency and phase response graphs. Would it be possible to share them?
Interesting. In the papyrus ARA crossover, the baffle step is a parallel filter, here for the TX version it is series/shunt?
I am still new to crossover design and learning quite a bit, but are there any design considerations to choosing parallel vs series filters for this?
In my terminology, series or parallel refers to how the network is connected to the driver. Hence, the shelf filter used for the ARA (and ARA-Be) is a series network (comprised of components connected in parallel), and the notch filter used for the ARA-TX is a parallel network (comprised of components connected in series). A passive filter is a voltage divider. The output voltage of the amplifier is shared by the load impedance (the driver and anything connected across it in parallel) and the series impedance sitting in front of it (i.e., between the amplifier and the load, thus acting as generator output impedance). This means that if you want to attenuate the output of the driver in some frequency range, you can either lower the load impedance (ARA-TX) in this area or increase the series impedance (ARA/ARA-Be) - or do a combination. I don't think you can generally say that one method is better than the other when it comes to equalizing the baffle-step (edge diffraction), it all depends... However, in certain situations you are left with just one option, though that is not the case here. Let's say you wanted to equalize the response of a full-range driver, which is (initially) connected directly to the output of the amplifier without any crossover network. In this case, you are going to need a series network to create a voltage divider. You can't just connect an LCR-network in parallel with the driver, as this will only change the load impedance, while the driver remains connected directly to the amplifier, which in most cases is a voltage generator with a low (often negligible) output impedance. You cannot rely on voltage division between the very low (and perhaps unknown) output impedance of the amplifier and the load, and besides, you would more or less short circuit the amplifier at the center frequency of the notch filter - not good. You don't want to be fighting your amplifier.
If you need to cancel out a significant/audible resonance (break-up peak) somewhere above the crossover point, I would always use a parallel network, as with the ARA-TX. You can easily use this in combination with the shelf filter, if you like. We do this with the Bromo kit. If you use a shelf filter, you will often need parallel branch between the series filter inductor and the shelf filter - either a single capacitor (making it a 2nd order filter) or an RC-network to compensate for the gradually increasing load impedance seen by the series inductor (this is to ensure sufficient roll-off and phase shift for optimum integration with the tweeter - depending on time delay, of course).
With the ARA-TX, I was determined to use a simple 1st order network, a single inductor in series with the woofer. This is doable thanks to the very low inductance of the voice coil (due to the extended copper sleeve on the center pole piece) and near perfect time alignment (a result of the inclining baffle). This way, you have to use a parallel LCR-network for baffle-step compensation, which is only an advantage here, I think. Not only was it easier to attain smooth equalization of the diffraction bump associated with the baffle-step (depending on the size and shape of the baffle as well as driver placement, you usually get a 2-3 dB bump nearly an octave above the center frequency on the baffle-step), but I also ended up with a smaller value series inductor (0.82 mH vs. typically 1-1.2 mH). Even though the baffle-step is below the (electrical) crossover point, the impedance of the series inductor is still sufficiently high for proper voltage division.
If you need to cancel out a significant/audible resonance (break-up peak) somewhere above the crossover point, I would always use a parallel network, as with the ARA-TX. You can easily use this in combination with the shelf filter, if you like. We do this with the Bromo kit. If you use a shelf filter, you will often need parallel branch between the series filter inductor and the shelf filter - either a single capacitor (making it a 2nd order filter) or an RC-network to compensate for the gradually increasing load impedance seen by the series inductor (this is to ensure sufficient roll-off and phase shift for optimum integration with the tweeter - depending on time delay, of course).
With the ARA-TX, I was determined to use a simple 1st order network, a single inductor in series with the woofer. This is doable thanks to the very low inductance of the voice coil (due to the extended copper sleeve on the center pole piece) and near perfect time alignment (a result of the inclining baffle). This way, you have to use a parallel LCR-network for baffle-step compensation, which is only an advantage here, I think. Not only was it easier to attain smooth equalization of the diffraction bump associated with the baffle-step (depending on the size and shape of the baffle as well as driver placement, you usually get a 2-3 dB bump nearly an octave above the center frequency on the baffle-step), but I also ended up with a smaller value series inductor (0.82 mH vs. typically 1-1.2 mH). Even though the baffle-step is below the (electrical) crossover point, the impedance of the series inductor is still sufficiently high for proper voltage division.
Thank you. That makes more sense terminology wise.
That is interesting as well
I have the TW29DN-8 and two MW-16P-8 in a 2.5 way, with my own crossover design (in an external box, using wago connectors so I can easily tinker with it). It already sounds amazing, but this post gave me a lot to think about in trying new options. I am currently using the series baffle step correction (1.2H + 8.2R), then into the two woofer circuit (each with their own filters). I will try exploring/modeling options with the parallel shunt filter.
I love these Satori midbass drivers with the low inductance motors. Such easy drivers to play with. (My other main speakers are a pair of the original Vienna Acoustics Bachs with the well liked Seas/Vifa 17cm woofer. The MW-16P-8 has a similar midrange ease to that driver, but with way more low end slam!)
@USXX Many thanks for explaining the ARA TX crossover, much appreciated.
This may be a daft questions but thought I'd ask anyway........
For the ARA TX did you consider a first order electrical for the tweeter as well. I did a quick model of the crossover with published data and if you remove the parallel 270uH/15ohm second order element on the tweeter and reduced the series capacitor from 3.9uF to 2.7uf you get almost the same on axis results for the tweeter and combines frequency and as good (if not better) null when reversing the tweeter polarity. The down side is a higher tweeter impedance peak. Also, if this is OK is there also any detriment to removing the 1ohm series resistor and increasing the first series resistor to 3.9ohm.
Sorry newbie questions but the idea of a first order electrical crossover (plus the notches) intrigued me. Also, I am happy to be told I am barking mad, I am still learning and not easily offended.
I.e. something like this -
Original
1st order tweeter ?
This may be a daft questions but thought I'd ask anyway........
For the ARA TX did you consider a first order electrical for the tweeter as well. I did a quick model of the crossover with published data and if you remove the parallel 270uH/15ohm second order element on the tweeter and reduced the series capacitor from 3.9uF to 2.7uf you get almost the same on axis results for the tweeter and combines frequency and as good (if not better) null when reversing the tweeter polarity. The down side is a higher tweeter impedance peak. Also, if this is OK is there also any detriment to removing the 1ohm series resistor and increasing the first series resistor to 3.9ohm.
Sorry newbie questions but the idea of a first order electrical crossover (plus the notches) intrigued me. Also, I am happy to be told I am barking mad, I am still learning and not easily offended.
I.e. something like this -
Original
1st order tweeter ?
@Ugg10 Not a daft question, at all.
You can certainly do this. I did try a pure 1st order network when I designed the ARA, and as you point out, the transfer functions are almost identical (see attached graph). However, in listening (with my setup), I found that it sounded slightly better with the LR-branch, especially at higher levels. As you can tell, my high-pass filter is practically a 1st order filter due to the large resistor in series with the inductor (it does not behave like a 2nd order filter). If you remove the LR-branch, the order of the series components (in front of the LCR-network) no longer matters, so it would only make sense to remove one of the resistors an increase the value of the other. Intuitively, it might be tempting to optimize for cancellation at the crossover frequency when reversing the tweeter polarity, and it is absolutely a good indication that the drivers are integrating well. However, if you move the microphone just a little bit off-axis, the picture changes completely (you will still see cancellation in a wide frequency range, though nothing close to null). What really matters when it comes to perceived sound quality is power response, so if you can achieve a flat on-axis response and a smooth (slightly tilted) power response at the same time, you're on the right track.
You can certainly do this. I did try a pure 1st order network when I designed the ARA, and as you point out, the transfer functions are almost identical (see attached graph). However, in listening (with my setup), I found that it sounded slightly better with the LR-branch, especially at higher levels. As you can tell, my high-pass filter is practically a 1st order filter due to the large resistor in series with the inductor (it does not behave like a 2nd order filter). If you remove the LR-branch, the order of the series components (in front of the LCR-network) no longer matters, so it would only make sense to remove one of the resistors an increase the value of the other. Intuitively, it might be tempting to optimize for cancellation at the crossover frequency when reversing the tweeter polarity, and it is absolutely a good indication that the drivers are integrating well. However, if you move the microphone just a little bit off-axis, the picture changes completely (you will still see cancellation in a wide frequency range, though nothing close to null). What really matters when it comes to perceived sound quality is power response, so if you can achieve a flat on-axis response and a smooth (slightly tilted) power response at the same time, you're on the right track.
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