Eight inch woofer testing, report

[DaveFred]

SB Acoustics SB23NACS45-8, approximately $127.00 each,

[DaveFred]

Free Air impedance,



In Box impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,



Quick and dirty 1800 Hz LR4 on the woofer, something realistic to go with my tweeter requirement.

[DaveFred]

Scanspeak 22W/8534G00 Discovery 8" Woofer, approximatly $100.00 each,

[DaveFred]

Free Air impedance,



In Box impedance,



Distortion 2.83 volts, 315mm,






Raw response 2.83v, 1m,



Normalized,



Quick and dirty 1800 Hz LR4 on the woofer, something realistic to go with my tweeter requirement.

[DaveFred]

And that ladies and gentleman concludes the Woofer portion of this Pageant (for now?)...

Next up...

Possible Tweeter candidates...

[Evil Twin]

Congratulations on completing the first phase of your rigorous testing process...

[DaveFred]

The woofers that have been selected to go on to the next round of competition based on a totally random weighting of bass extension, frequency response, smoothness of roll off, breakup modes, distortion and my own personal whimsey are as follows,

Dayton RS225-8
SB Acoustics SB23NRXS45-8
Seas U22REX/P-SL
Scan Speak 22W/8534G00
Dayton RSS210HF-4
Wavecor SW22BD02
Monacor SPH-200KE -Probably should not be on this list, but I want to test further
Peerless HDS-P830869 -First sample might have been damaged, want to test further

Second round, where I will be level matching the woofers and testing for distortion @ 315mm @ 105dB (=95dB 1m or 85dB 3m) as well as possibly matching to PR's to see what bass extension each driver can do,

Eliminated,

SB Acoustics SB20PFCR30-8 - A great value, just not in the same league as some of the other more (sometime much more) expensive choices in this testing
Ciare HWB200 - Very large rising 3rd order distortion up to about 1.5KHz, large dip in response at 1.3KHz
Eton 8-412/C8/32 HEX Symphony II - This one is a big disappointment for me, I had high hopes for this driver, bad rising 3rd order distortion around 1KHz.
HiVi - Suited to a looking after the bottom of a three way, not a two way stretch like I am looking for.
Human 8 - Not good.

Your thoughts so far?

[PANDINUS]

My personal choice of those tested is the Dayton RS225-8

[Reet]

Dayton RS225 - surprisingly decent given the testing provided, will be interesting to see if its performance completely falls apart at higher SPL
Seas U22REX - smoothest response of the bunch, but it's a poly cone so what do you expect?
Scan Disco 22W - Very good overall, looks good, performs well, and is well priced. A valiant successor to the old Vifa P/M/MG line.
Dayton RSS210HF - This one could be a challenge for a 2-way crossover, but breakup is a laser beam short band, if it can be notched out properly it could be excellent. I would be concerned a bit with inductance modulation over excursion moving the notch frequency around.
Wavecor SW22 - Honestly I'd skip this one given the Dayton RSS210 has higher breakup frequency and shorter band of resonance. Wish you would have included WF223 from Wavecor instead.
Monacor - Ugly speaker, okay performer.

[tktran]

Each time I see a testing that includes a RS225; I’m wondering why I didn’t buy a pallet load of them; when they were first introduced and tested by MarkK almost 20 years ago…

https://web.archive.org/web/20080828140215/http://www.audioheuristics.org/measurements/Testing/Woofer2/8%20inch%20woofer%20test.htm

IIRC introductory price was under $40…

[DaveFred]

I am getting a little out of order in how I wanted to post things, but I didn't have the opportunity to do the woofer testing I wanted today, so I thought I would post some tweeter data while I had the time. Note that most of the bundling in the 3000Hz range is due to the less than optimum baffle I am using for testing.

SB Acoustics SB29RDAC-C000-4, approximately $65.00 each

Data Sheet,



Tweeter Pics,







Impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,

[DaveFred]

SB Acoustics SB26STWGC-4, approximately $95.00 each


Data Sheet,



Tweeter Pics,








Impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,

[DaveFred]

Wavecor TW030WA13, approximately $95.00 each

Data Sheet,




Tweeter Pics,







Impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,

[DaveFred]

Seas 27TBCD-GBDXT, approximately $80.00 each,

Data Sheet,



Tweeter Pics,







Impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,

[DaveFred]

Bozhen Audio Lab CQ66, approximately $100.00 each

Data Sheet,




Tweeter Pics,







Impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,

[PANDINUS]

SB Acoustics SB29RDAC-C000-4 and Seas 27TBCD/GB-DXT are also measured on hificompass.com The distortion results are quite similar. Good work. But you only measure up to 20kHz and that's why the increased distortion from the resonances of the AL membrane in Seas, is to 28kHz, does not appear in your graphs.

[DaveFred]

Each time I see a testing that includes a RS225; I’m wondering why I didn’t buy a pallet load of them; when they were first introduced and tested by MarkK almost 20 years ago…

https://web.archive.org/web/20080828140215/http://www.audioheuristics.org/measurements/Testing/Woofer2/8%20inch%20woofer%20test.htm

IIRC introductory price was under $40…

I don't want to go too sideways here, but where did Mark K go?

[Evil Twin]

MarkK moved his hobby focus to other areas of activity in life- and dropped his web site. The domain is available.

[tktran]

Probably stopped obsessing and learnt how to just enjoy the music.

He still lurks over and DIYAudio and ASR but rarely posts.

the rest of us are searching for audio nirvana; even though deep down we know there’s no such thing.

[technodanvan]

I just like the gear...and the methods for creating it. Really enjoying your work Dave!

[tktran]

I enjoy your work too Dave. Thank you.

you’ve spent a considerable sum of funds and time for testing as well as sharing your data. Did you acquire the drivers just for testing? Or are they part of an existing collection, acquired over time?

[DaveFred]

I enjoy your work too Dave.

Thank you,

Did you acquire the drivers just for testing? Or are they part of an existing collection, acquired over time?

A little bit of A and a little bit of B.

Some guys like chasing little white balls around on the lawn, or pulling fish out of water, I like doing this for fun.

[Evil Twin]

Thank you,



A little bit of A and a little bit of B.

Some guys like chasing little white balls around on the lawn, or pulling fish out of water, I like doing this for fun.

I fully appreciate and commend your viewpoint... as well as the difference.

[tktran]

MarkK will be back; in a couple of years when he’s retired.

if I was retired I would live in my workshop…

[Evil Twin]

Probably stopped obsessing and learnt how to just enjoy the music.

He still lurks over and DIYAudio and ASR but rarely posts.

the rest of us are searching for audio nirvana; even though deep down we know there’s no such thing.

Ah, but when you have touched and experienced the edges of it at times, one cannot drop the search and effort so easily...

And it is reasonable to consider the journey analogous to various arts... just because you have written one song, or painted one picture, does not mean you are ready to end those endeavors.

[DaveFred]

One last woofer to add to the list, Wavecor WF223BD01, approximately $200.00 each,

[DaveFred]

Free Air impedance,



In Box impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,



Quick and dirty 1800 Hz LR4 on the woofer, something realistic to go with my tweeter requirement.

[DaveFred]

And one last tweeter, Scan Speak D2608/913000, approximately $95.00 each,

Data Sheet,



Tweeter Pics,







Impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,



(Arta was doing weird stuff, ignore below 300Hz)

[tktran]

Some quick comments

For people who are experienced with waveguided dome tweeters- can you comment on the SEAS 27TBCD-GBDXT and SB SB26STWGC-4 "waveguided" domes?

[Reet]

I'm not sure what sort of information you're looking for beyond the data already provided. Both tweeters are great options, even with a small waveguide there are still great benefits. Compared to domes with flat face plates, primarily the effects of baffle diffraction are reduced, as well as the directivity problem that is often observed ~3kHz range in most 2-way speakers with 6"+ woofers. It allows for better overall power response & DI.

For the two tweeters mentioned, the SB option provides perhaps a bit better HD performance from 1-2kHz, however with a crossover implemented it is probably a wash. DXT offers a frequency response that is fairly easy to work with, however with the drooping top end response of the DXT, the SB option allows for higher overall system sensitivity. If you're interested in this type of driver, I would also consider Wavecor TW030WA11/12 which is a bit larger dome and waveguide, unfortunately Dave didn't include it here because the face plate is just slightly too large for what he's doing.

[wushuliu]

Great stuff. Would love to see how the (Audio Select now Multicomp) 55-5670 stacks up against these other woofers. It has quite a few fans who prefer it to the RS225 - and at the old RS225 price.

[tktran]

I’ve not seen a single measurement on that. And Dave Fred has stated that he’s not going to acquire any more for testing.

Do you have any measurements of 8” woofers to share?

[DaveFred]

I am running out of time to build the speaker I need to build, so I am going to have to cut my testing short here at this point and declare not neessarily a winner, but a top candidate for what I am trying to do. If I had time for further testing, I might find that I didn't make the best choice, that other drivers would have been better, but due to time and what I have learned so far, this is what I am going with,

Wavecor WF223BD01 woofer, Seas Prestige 27TBCD/GBDXT tweeter and Dayton DSA270-PR passive radiator.



Look for a new thread about the build.

Thanks for following along,

David.

[wushuliu]

I’ve not seen a single measurement on that. And Dave Fred has stated that he’s not going to acquire any more for testing.

Do you have any measurements of 8” woofers to share?

Not sure why I got a snippy response and this isn't the only forum where woofers are measured. I have no expectations that DaveFred would measure a driver just because I mentioned it.

[tktran]

Sorry if that sounded snippy. That was not the intent. I too have read about that MCM woofer, as well as the 6.5” one, but never seen measurements. Apparently they have a copper in the motor and low Le; I would like to see that woofer measured and compared to the Reference, which is (was) the cheap but good RS225 that IMHO started it all.

I think the WF223BD01 is a good choice, but can sourcing can sometimes be difficult. It’s good that PE carry Wavecor; I’d like to see the Wavecor go head to head with the Purifi.

[joecarrow]

Thanks for sharing all this data!

I have the RS225 that I was considering for my project, but in my test box I found the off-axis above 1khz started to get funny. Perhaps it was my test box. It does seem to hold up to fairly high drive levels though.

I also have a pair of the Peerless HDS-830869, and I like them well enough to do more with them. Unfortunately it seems like they're discontinued. Are you still able to buy them?

My project is focused on home theater, so I'm also starting to look at smaller pro woofers, specifically the SB Audience Rosso 6M-150D.

That tweeter you've selected has been in some very good speakers, so I think you're going to make something good here.

[Efalegalo]

Free Air impedance,



In Box impedance,



Distortion 2.83 volts, 315mm,





Raw response 2.83v, 1m,



Normalized,



Quick and dirty 1800 Hz LR4 on the woofer, something realistic to go with my tweeter requirement.

Dave - any chance you can post the impulse response for the RSS210 - just in case you have it saved? - I'm getting an odd ringing or sort with both of my test samples. Now - it very well could be the box I'm using (because it's just something crude for a quick measurement setup). Maybe there is something wrong with my setup - but I'm not getting the same issue with my RS225s

[technodanvan]

JonMarsh might also have this data.

[Reet]

Just a metal cone speaker doing what metal cones do...

[JonMarsh]

Yup. And I'd expect something similar from the RS225- higher up in frequency.

This is not a direct impulse measurement, but a convolution done in Fuzzmeasure from the sine chirp used in the measurement:





You can see this "ring" is at the breakup frequency of the cone, as well be seen in the next graph. It's high Q, but narrow in spectrum. Some breakup modes, like with RS225, have a wide spectrum and a substantial dip before the breakup.


This is the SPL measurement from which this was derived- it's QNF (quasi near field, about 10", to preclude baffle step and roughly simulate IB result, but note that the actual enclosure is PR loaded on the back side, and there is little PR contribution with this method to the output:







One can see that the peak level of the break up mode is about 15 dB higher than the normal response level. Its high Q and narrow bandwidth make it easy to suppress, including suppression of resonance amplification of distortion products.

[svp2000]

DaveFred, great work measuring that many drivers!

I am into 2 way system with very very similar requirements as OP, but:
-Primarily music listening. Various, mostly EDM, pop, lo-fi remixes and so on
-Thinking about bass reflex, lets say of 70L (2.5 cu ft) volume is the limit OR some kind of transmission line also ok
-Small monkey coffins or towers. Does not matter.
-Preferably no metal cones... I made speakers with Dayton RS100 for friend, he likes the sound, I don't.
-Preferably more 2nd order distortion than 3rd. Just pleasant warm sound
-Overall good price/performance ratio. EU location, good driver availability and pricing
-Still haven't decided with tweeter, but want to cross a bit higher, maybe 2000-2100Hz range, but that is not decided . Also - want to invest relatively more into woofer and less into tweeter.
-Simple crossover is advantage, don't want to spend ridiculous amounts of money to tame some "fashionable" driver.

What do I see from the graphs:


Seas U22REX-P-SL

Pros:

• That thing is a pornstar of speaker drivers! Like Dayton RS series on steroids! Visually I like it very much
• Very aerodynamic alloy basket
• Relatively low and consistent distortion up to roll of. Everything there looks like textbook woofer
• 2nd order distortion is more than 3rd
• Very reputable brand
• Widely available in EU
• Lots of power
• Probably still good price-performance ratio

Cons:

• Not cheap, 180-210EUR in EU
• In condition tested looks like not much bass extension, is it suitable for BR and sub 100Hz duties?
• Just 4mm Xmax +/- ????

SB Acoustics SB23NRSX45-8

Pros:

• Affordable priding, from 95 to 110 EUR
• One of most available brands in EU
• Stiff composite cone
• Visually nice, solid, simple.
• Not much distortion
• Reasonable breakup/rolloff at high frequencies
• Very good price/performance ratio

Cons:

• Brand is known for not being very consistent with T/S parameters. Do not know much about the others but probably not amongst the leaders
• More distortion in sub 100Hz
• Not much of the bass extension in tested conditions

Ciare HWB200-4

Pros:

• Very affordable pricing, from 80 EUR in EU
• Solid aerodynamic basket
• Visually nice, solid, simple.
• Reasonable distortion
• Lots of power
• Reasonable rollof

Cons:

• 3rd harmonics are just dominating
• Not widely available in North/Central EU

SB Acoustics SB20PFCR30-8

Pros:

• Cheap, from 60(!) EUR
• One of most available brands in EU
• Stiff composite cone
• Visually nice, solid, simple.
• Probably best price/performance ratio

Cons:

• 3rd harmonics are just dominating
• Not much bass in tested conditions

I just rejected all the aluminum cones... Other drivers are rejected because not very good, or too expensive, or are not cheaply available in EU, or cannot be crossed directly to tweeter, or are just ugly looking.
My heart is with Seas drivers, but it is exactly twice as expensive as SB Norex series. At half the price I will get 90% performance or even more. The other two in the list: paper SB and Ciare could be OK for me and good value for money, but I am afraid that dominating3rd and 5th order harmonics can be tiresome during extended listening. Scan Speak has distortion spikes in crossover region.

So, the question is - will SB NRX series be ok or I should go with SEAS? Are they ok with bass-reflex or ML (MLTL)?

[DaveFred]

Sometimes a more expensive choice is just a more expensive choice.

Look my build with the Dayton 8",

https://www.htguide.com/forum/forum/mission-possible-diy/945065-davids-new-8-1-build-dayton-rs225-8-scanspeak-d2604-833000-in-wg300-~42-litre

David.

[digitalthor]

Excited to hear about your finding with the Wavecor WF223BD. Any news on the project?

[Ally Fantastic]

DaveFred, great work measuring that many drivers!
SB Acoustics SB20PFCR30-8
Pros:

• Cheap, from 60(!) EUR
• One of most available brands in EU
• Stiff composite cone
• Visually nice, solid, simple.
• Probably best price/performance ratio

Cons:

• 3rd harmonics are just dominating
• Not much bass in tested conditions

I am new to the forum so... Hi All!
I came here while looking for some tests of SB20PFCR30.
svp2000 says above " 3rd harmonics are just dominating" and "Not much bass in tested conditions". What are these statements based on? Show me the measurements?
DaveFred I read you eliminated SB20PFCR30-8 from your tests as "out of the league". Could you explain what you do not like about this driver? Do you agree with the statements above?
I am planning my next design to be a TL box. The box itself is planned to be based on Ekta-TL design by Troels. I am just planning to replace the drivers with some more economic ones. Naturally I will make the necessary changes in the box and XO design to accommodate for the new drivers. I just like the concept of the original box, the way the mid driver compartment is blended into TL and box design.
And frankly SB20PFCR30-8 was the first choice. This driver is very attractively priced in Europe and gets very good reviews. Most people say it has very good linearity, so where does the statement about high 3rd order harmonics come from? It is recommended as a driver with very good, low bass, and here I read "not much bass" .... hmmm.
This driver is very very very popular but it is very difficult to find any reliable information about it, especially well made measurements. DaveFred I wish you would put it into tests, show the distortions, verify T-S parameters. Maybe it is out of your league but I think it deserves a few minutes of your time because of its popularity.
Show me any other 8" driver in the $50 range that can compete with this one. I did not find any other driver suitable for a descend quality diy design (I consider only drivers with at least 90dB sensitivity). Sorry, but $200 drivers are out of my league.

[technodanvan]

Excited to hear about your finding with the Wavecor WF223BD. Any news on the project?

I'm pretty sure Dave completed that build in another thread with the Seas DXT tweeter and a Dayton PR.

https://www.htguide.com/forum/forum/mission-possible-diy/929624-dave-s-8-woofer-104mm-tweeter-speaker-build