I'm looking for options among 8" woofers, for a 3 small 3 way assisted by sub. The cabinet is around 13 litres net, which gives me sealed f3 between 60 and 80 Hz from the drivers listed in poll. Upper range will be around 200-250, where Satori MW13 takes over. This setup will be powere by a Hypex plate amp (50 clean watts into 8 ohm/100 in 4 ohm), so Linkwitz Transform is an option. I aim at peaks reaching 90dB at the listening position, which is about 2,8m away from the speaker.
This project was originally meant as a 2 way, with 5" midwoofer going all the way to 80 hz ina vented cab. When I realised how much time and effort it costs me to finish this, I switched my priorities and decided that 5" based two way will be too much of a compromise and I want to relieve the mid from the hardest work below 200-250 Hz, which is as high as driver spacing allows to stay within 1/4 of XO wavelenght. So I'm adding a woofer to an ongoing build, which means I have to fit the drivers to the enclosure and not the other way around. This means that I have pretty limited space (ita around 16,5 litre but the Hypex plate needs its own subenclosure which will take some space), and limited baffle width - which is 226 mm. This throws SB23 Norex or Alu woofers out of the window with their largest-in-class flanges.
Initially I planned to use RS225P-4A as a widely recommended go-to 8" woofer with low distortion. Unfortunately, then I started reading about Qms and Rms, on which aspects Dayton looks surprisingly poor compared to rivals from Seas, Scan Speak or SBA.
As this will be an active design I can add some EQ to overcome highish F3 but theres also the problem of Q. Of those listed, only Seas will manage a Butterworth 0.707 alignment without EQ, not to mention that it would be nice to also try more damped alignments. RS225 should also manage if I stuff the box a lot, same with SB20. Most other 8" woofers will need some EQ to get to 0.7 Qb and even more for 0.6 or 0.5.
Even though all of listed drivers are pretty popular, theres little info comparing them.
As mentioned, Dayton fares the worst on Qms and Rms terms but poeple seem to be quite happy with it. It also seems like it has the lowest THD between 50 and 200Hz.
Seas fits the bill on paper but its an old design amd I cannot find any THD measuremenets, even though it was used in one of Troels Gravensen designs probably makes it a safe bet. Its also the most expensive of the lot 🙂
Scan Speak looks like the the best pick (higher Qms and lower Rms than Dayton and Seas), has overall low distortion and wide band if I wanted to utilise it in a future 2 way but its not really happy in small boxes. 8" Scan Revelator would fit the bill but its way out of the price range.
SB20PFC has some surpisingly good THD figures, highest Qms and lowest Rms, of the bunch, all despite a plastic basket and at less than 50% of the price of Daytons. Looks good on paper but its cheap so its not really popular on builds that are not super budget oriented.
I also looked at Peerless as I have an 10" XLS sub but HDS 8" woofer has highish 4th harmonic and seems like its happier with lower midrange than bass below 100 Hz. There's also an 8" SLS but at Qts of above 0.6 I could only use it in an open baffle, although I didn't check if I have enough power to do that.
Maybe there's some gem that doesnt cost more than Scan Discovery or Seas Prestige that would make my system happy? What would be Your pick?
This project was originally meant as a 2 way, with 5" midwoofer going all the way to 80 hz ina vented cab. When I realised how much time and effort it costs me to finish this, I switched my priorities and decided that 5" based two way will be too much of a compromise and I want to relieve the mid from the hardest work below 200-250 Hz, which is as high as driver spacing allows to stay within 1/4 of XO wavelenght. So I'm adding a woofer to an ongoing build, which means I have to fit the drivers to the enclosure and not the other way around. This means that I have pretty limited space (ita around 16,5 litre but the Hypex plate needs its own subenclosure which will take some space), and limited baffle width - which is 226 mm. This throws SB23 Norex or Alu woofers out of the window with their largest-in-class flanges.
Initially I planned to use RS225P-4A as a widely recommended go-to 8" woofer with low distortion. Unfortunately, then I started reading about Qms and Rms, on which aspects Dayton looks surprisingly poor compared to rivals from Seas, Scan Speak or SBA.
As this will be an active design I can add some EQ to overcome highish F3 but theres also the problem of Q. Of those listed, only Seas will manage a Butterworth 0.707 alignment without EQ, not to mention that it would be nice to also try more damped alignments. RS225 should also manage if I stuff the box a lot, same with SB20. Most other 8" woofers will need some EQ to get to 0.7 Qb and even more for 0.6 or 0.5.
Even though all of listed drivers are pretty popular, theres little info comparing them.
As mentioned, Dayton fares the worst on Qms and Rms terms but poeple seem to be quite happy with it. It also seems like it has the lowest THD between 50 and 200Hz.
Seas fits the bill on paper but its an old design amd I cannot find any THD measuremenets, even though it was used in one of Troels Gravensen designs probably makes it a safe bet. Its also the most expensive of the lot 🙂
Scan Speak looks like the the best pick (higher Qms and lower Rms than Dayton and Seas), has overall low distortion and wide band if I wanted to utilise it in a future 2 way but its not really happy in small boxes. 8" Scan Revelator would fit the bill but its way out of the price range.
SB20PFC has some surpisingly good THD figures, highest Qms and lowest Rms, of the bunch, all despite a plastic basket and at less than 50% of the price of Daytons. Looks good on paper but its cheap so its not really popular on builds that are not super budget oriented.
I also looked at Peerless as I have an 10" XLS sub but HDS 8" woofer has highish 4th harmonic and seems like its happier with lower midrange than bass below 100 Hz. There's also an 8" SLS but at Qts of above 0.6 I could only use it in an open baffle, although I didn't check if I have enough power to do that.
Maybe there's some gem that doesnt cost more than Scan Discovery or Seas Prestige that would make my system happy? What would be Your pick?
Unfortunately very hard to find. SDX7 in 14 liters gets you lower than needed with no DSP. If you are tyoing to fill an existing hole it might be too small.
dave
dave
Thanks Dave, this looks interesting, although I was hoping that since I dont need very deep bass I could get away with somewhat higher sensitivity. I'll see how availability looks here in Europe.
Am I correct in thinking that Qb and related impulse response only matters around f3, so if I use a woofer that goes down in my box to say 60 Hz, and filter it at 80Hz, then rollof and transient behaviour is defined by filter Q and not by Qb?
This would mean that I should either go for low Qes, high Mms woofer for low f3 in a small box or use a higher efficiency driver, force the f3 to 50-60 hz with a transform or plain shelving, filter it at 70-80 Hz with Q I like best and forget about Qb.
Am I correct in thinking that Qb and related impulse response only matters around f3, so if I use a woofer that goes down in my box to say 60 Hz, and filter it at 80Hz, then rollof and transient behaviour is defined by filter Q and not by Qb?
This would mean that I should either go for low Qes, high Mms woofer for low f3 in a small box or use a higher efficiency driver, force the f3 to 50-60 hz with a transform or plain shelving, filter it at 70-80 Hz with Q I like best and forget about Qb.
I vote 22w4534 Wonderfull cone and very easy to work with.
If money permits Linkwite 22mg, an other level of transparency.
If money permits Linkwite 22mg, an other level of transparency.
Thanks @jerome69, I'm leaning towards the Scan myself. Did some simulations today and its much happier to do what I'm asking than the Dayton, especially if I use a transform to extend the f3 to mid 50's to get a more textbook rolloff around 80 Hz.
On a more qualitive side I also enquired about at my local shop and was told that Seas is a tad slow (heavy cone, moderate sensitivity), and the Daytons somwhwat less refined in bass compared to Scan (matter if Qms/Rms I presume).
Can't find any info about this Linkwite woofer, all I was getting in Google were some car audio subs.
On a more qualitive side I also enquired about at my local shop and was told that Seas is a tad slow (heavy cone, moderate sensitivity), and the Daytons somwhwat less refined in bass compared to Scan (matter if Qms/Rms I presume).
Can't find any info about this Linkwite woofer, all I was getting in Google were some car audio subs.
Thanks for the correction, It was a typo.
Not so easy to find a good 8" to handle the range 50...2000 Hz. I am a fan of design 8"+1". The list of 8" candidate for this design is very small. You should no be dissapointed with the scanspeak and the seas. I use the ss 22w8534 and w22nx001 and very happy with them.
Test of the ss :
https://www.hifisound.de/out/media/...jJr285v3cUSaumS/v9cF8VxhYNyhU91yLp5FWCg==.pdfNote you can go up to 500Hz, a 8" is not directive below. In my list some Audax and Monacor can do the job but haven't test then. I use the MW13 too in a 4 way design 😉
Not so easy to find a good 8" to handle the range 50...2000 Hz. I am a fan of design 8"+1". The list of 8" candidate for this design is very small. You should no be dissapointed with the scanspeak and the seas. I use the ss 22w8534 and w22nx001 and very happy with them.
Test of the ss :
https://www.hifisound.de/out/media/...jJr285v3cUSaumS/v9cF8VxhYNyhU91yLp5FWCg==.pdfNote you can go up to 500Hz, a 8" is not directive below. In my list some Audax and Monacor can do the job but haven't test then. I use the MW13 too in a 4 way design 😉
While there is nothing wrong with your plans, you could also aim for a 6,5 to 7" driver (if your SPL requirements are right). Furthermore, about any 8" will do, as none of them will show serious breakup in the working region, distortion in this frequency range often isn't that malign and your requirements in general aren't that extreme.
I wouldn't choose on behalf of the Qms-discussions here. Some contributors obviously don't have a clue about the design compromises in a speaker unit and Qms/Rms are just aggregates of quite a few design choices. Rather pick higher order uneven distortions at higher SPL/drive voltage or excursion as a criterium. Measurements of these are available for various candidates at the usual (thank you contributors) websites.
I wouldn't choose on behalf of the Qms-discussions here. Some contributors obviously don't have a clue about the design compromises in a speaker unit and Qms/Rms are just aggregates of quite a few design choices. Rather pick higher order uneven distortions at higher SPL/drive voltage or excursion as a criterium. Measurements of these are available for various candidates at the usual (thank you contributors) websites.
An LT is a huge distortion generator as it will easily exceed the X-max of your driver. Do the modeling!
Getting to 60 in an 8 is simple. Many great drivers. Actually a lot of 6's can do it. Might I suggest looking at the CSS and Purifi drivers along with the SB/Satori?
I know of no 8 that can remain well behaved high enough to reach a 1 inch dome. Any dome I know of. A 6 is rare, more 5's can do it. If using a sub, and with a decent crossover around 70 or so, a 5 or 6 will produce all the SPL your ears can handle. A 8 inch 2-way was the budget seller back when we had 2 inch cone tweeters.
Getting to 60 in an 8 is simple. Many great drivers. Actually a lot of 6's can do it. Might I suggest looking at the CSS and Purifi drivers along with the SB/Satori?
I know of no 8 that can remain well behaved high enough to reach a 1 inch dome. Any dome I know of. A 6 is rare, more 5's can do it. If using a sub, and with a decent crossover around 70 or so, a 5 or 6 will produce all the SPL your ears can handle. A 8 inch 2-way was the budget seller back when we had 2 inch cone tweeters.
Agree with tvrgeek ... if that 1" dome tweeter isn't in a waveguide you have zero chance of having a smooth directivity hand off from an 8" mid.
I agree about LT being a distortion generator if I aimed for 20Hz ina sealed box but I did the modelling and for Scan and Seas xmax is not a problem. I would use a transform only to extend the resonance to mid 50's but still highpass at around 80 to my sub. Seems pointless but as I understand it this will make the Q of the smallish box irrelevant and filter Q will dominate driver's behaviour near crossover. Please correct me if I'm wrong.
Also, while the 5 inch Satori that I have can reach 80 Hz at -6 db in a vented box I designed for it, I should get much better distortion profile and way less IMD if I relieve it with a 200 hz LR2. My motivation is that I have already spent a year building my sub and center channel and am halfway through doing the mains under discussion here, and I view adding a 8" woofer as the easiest way of lowering the overall distortion and up the performance. I have the space (limited but still), I have amp channels, I can fork out for a Scan Discovery, so why not make it a 3 way 🙂
Also, 6" and 7" woofers dont look as clean at and below 100 hz as 8" woofers. Even Purifi 6.5 inch wont change the fact that bass calls for displacement and its much easier and cheaper to do it with the largest woofer size you can fit.
Agree a 8" has twice surface of a 6", better for a lower mid and cheaper.
8" + 1" can work well, just a matter know-how 😉
Milus let us know about your progress 😉
8" + 1" can work well, just a matter know-how 😉
Milus let us know about your progress 😉
@puppet there are 8" subwoofers and 8" "smoothers" such as Scan Discovery under discussion or Peerless HDS 8". SB23NRX also has pretty nice, wide directivity maintained up to 2kHz if I recall correctly. Use it with a "tank" tweeter such as SB29RDNC which can handle crossover anywhere between 1k and 2k (as per Zaph's xo contest) and there You go 🙂 SB26ADC which I use is also pretty fine crossing at 1,5-2kHz. There options for each design choices.
@markbakk I have too little experience to tell if high Qms/low Rms is neccessary. I can only guess it is not since Daytons RS225 and RS270 are so popular with Qms clearly contributing to driver damping just from looking at the difference between Qes and Qts. I guess that Qms/Rms is only important when we have a driver that is well behaved in its intended application, which the Dayton clearly is when we look at its pretty THD graphs. Its pronably a safe choice but on the other hand Scan with its slightly higher Sd and Qms is not prohibitively more expensive.
@vacuphile if only it wouldn't be wider than my baffle I would have probably gone for it, those 8" SB woofers have stellar specs at this price point.
@jerome69 This Linkwitz/Seas woofer surely look nice but what made my jaw drop were these distortion audibility thresholds, 2% for 3rd harmonic at 200 Hz and about 5% for 100 hz? Why would people even bother with subwoofers if 5-10% distortion od inaudible????
@markbakk I have too little experience to tell if high Qms/low Rms is neccessary. I can only guess it is not since Daytons RS225 and RS270 are so popular with Qms clearly contributing to driver damping just from looking at the difference between Qes and Qts. I guess that Qms/Rms is only important when we have a driver that is well behaved in its intended application, which the Dayton clearly is when we look at its pretty THD graphs. Its pronably a safe choice but on the other hand Scan with its slightly higher Sd and Qms is not prohibitively more expensive.
@vacuphile if only it wouldn't be wider than my baffle I would have probably gone for it, those 8" SB woofers have stellar specs at this price point.
@jerome69 This Linkwitz/Seas woofer surely look nice but what made my jaw drop were these distortion audibility thresholds, 2% for 3rd harmonic at 200 Hz and about 5% for 100 hz? Why would people even bother with subwoofers if 5-10% distortion od inaudible????
Looking at both frequency responses, I don't see it. Both tweeters you've suggested are pretty much omni around 2.3khz and till 3khz respectively. The 8"ers directivity start diverging around 1khz. Off axis responses will not match up without a waveguide on the tweeter.
Directivity plot will resemble a pine tree.
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I think the satori is more than adequate to do the job. It should be noted that excursion is minimum at port tuning frequency. So set the port to about 80-90Hz. What causes severe excursion is actually those frequency below port tuning. For a given power, excursion will peak at around probably 150Hz, so actually excursion won't be much. So to reduce excursion, what is important is a high pass with steep slope.
A 200Hz low pass is also not that great of an idea, you would need iron core inductors rather than aircore and that potentially will introduce more distortion....
A 200Hz low pass is also not that great of an idea, you would need iron core inductors rather than aircore and that potentially will introduce more distortion....
SB20 is tough to beat. IMO sounds great with good kick. I have mine in 12-15 liter cabinet with LT to 40 hz.