OA-14: what should it sound like?

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Infinitely Baffled
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Re: OA-14: what should it sound like?

Post by Infinitely Baffled » Wed 10 Apr 2019, 14:07

Really helpful post, Rob. Many thanks for taking the time to talk me through that.
Many thanks also to Momus.
Regards
Infinitely Baffled

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STDI!
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Re: OA-14: what should it sound like?

Post by STDI! » Wed 10 Apr 2019, 20:06

therob wrote:
Wed 10 Apr 2019, 12:40
....
What is a standard carlsson driver? The SC165? (if so, you're in luck, grafpro has ready filters for that)! The B65OA-IV? If so, I'd mail grafpro asking him what he thinks (he's the man when it comes to this!).

However, you should know that the B65OA-IV is really poor choice of woofer to use in oa14 (a 35L cabinet tuned to 30hz) when that woofer really works best in a *really* small cabinet, ~5L tuned to ~60hz (at least according to the T/S parameters).

I'm sry I cant just tell you "press that button and everything will sound perfect!".

//Rob

P.S. If you tried adjusting the jumper and you still get *really* bad sounding treble, then I'd check the tweeters one - by - one to see if one of them makes really ugly sounds (probably broken) and then try and first see if I could get my hands on used mt20 tweeters somewhere.
I don't agree B65oaIV beeing a "really poor chioce". It's the one carlssonplanet recommend. I have compared (more than once) original SC165 side by side with B65oaII and B65oaIV in OA14 and others. I can't hear a big, if any, difference. If you don't have SC165 (and properly refoamed) B65oaIV must be the best replacement in that pricerange. Satori is a bit more expensive.

When using B65oaII och B65oaIV you should replace one capacitor (or add) to a total of 15 uF, original is 10uF. In all other ways the filters are the same.

You can listen to the tweeters one by one through a cardbox tube (such as in a toilet paper role, but longer). Then you might be able to here if one is "broken".
OD-11(T22+B65OAII), 2xOA12, 3xOA12(T22+B65OAII), 7xOA14, 2xOA50, 2xOA52.2, OA52.LE, OA52.N, 2xL8, SC6, SC6.2

therob
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Re: OA-14: what should it sound like?

Post by therob » Wed 10 Apr 2019, 22:20

STDI! wrote:
Wed 10 Apr 2019, 20:06
I don't agree B65oaIV beeing a "really poor chioce". It's the one carlssonplanet recommend.
Whops! My bad! I sincerely apologize! It wasn't my intention at all to "talk shit" about it. I just ran a few quick simulations in Basta! and other T/S simulators and the results there didn't look good. I tried w/ both manufacturer reported T/S parameters and the T/S parameters that grafpro has measured and posted on carlssonkult.se.

The satori driver isn't actually that much more expensive: https://www.blackdotaudio.eu/sb-acousti ... p-109.html (you need to click the english flag in order to get it in... english/€)
Thats ~115 €, so, ~1150 kronor vs ~900 kronor for the b65oa-iv.

Again I apologize for causing confusion!

Has anybody btw measured the bass response of a oa14 w/ b65oa-iv outside against a wall? I'd be really interested to see how it performs!

//Rob

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Re: OA-14: what should it sound like?

Post by momus » Thu 11 Apr 2019, 15:47

I've been using SC 165 in OD 11, and OA 14 for most of my life. The very BIG difference with Satori is the "lack" of distorsion (third). The OD 11 was replaced by OA !4 because distorsion in the OA 14 was lower. Then I changed to OA 50.3. Then I changed to Satori (phoned Grafpro first). I did not change any filters when I put in my Satoris. I can't hear any difference. (well I cannot hear difference between CD´s snd Bluetooth)

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Re: OA-14: what should it sound like?

Post by therob » Thu 11 Apr 2019, 16:16

momus wrote:
Thu 11 Apr 2019, 15:47
I've been using SC 165 in OD 11, and OA 14 for most of my life. The very BIG difference with Satori is the "lack" of distorsion (third). The OD 11 was replaced by OA !4 because distorsion in the OA 14 was lower. Then I changed to OA 50.3. Then I changed to Satori (phoned Grafpro first). I did not change any filters when I put in my Satoris. I can't hear any difference. (well I cannot hear difference between CD´s snd Bluetooth)
Yes, the distortion is the main problem w/ the old drivers, and that is basically the reason people are looking to switch them out for something a little more 'modern' since that is one thing that really has gotten better over the years.

I'm not really sure I followed you all the way there, but are you saying that the drivers in od11 make more distortion then those of oa14? The drivers should be the exact same make and thus sound exactly the same (although, I guess some of them could've aged differently).

And are you saying that you can't hear any difference between the original oa50(.3) drivers and satoris? Well, I guess that would mainly be cause the lower distortion of those drivers.

I doubt if anyone can hear any difference between bluetooth/cd/spotify, but I'm not here to debate that.

I guess if there is no audible distortion and the frequency response is flat enough, there's really no reason to change things up.

The main debate here as I understood it is if the tweeters would give a considerable cleaner sound, and I think that it has basically been proven by grafpro and his measurements that it would.

//Rob

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Re: OA-14: what should it sound like?

Post by Infinitely Baffled » Mon 15 Apr 2019, 11:09

The last couple of posts suggest that the mid/bass drivers are also a source of third order harmonic distortion. I thought the distortion problem was associated solely with the tweeters?
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IB

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Re: OA-14: what should it sound like?

Post by therob » Mon 15 Apr 2019, 17:09

Infinitely Baffled wrote:
Mon 15 Apr 2019, 11:09
The last couple of posts suggest that the mid/bass drivers are also a source of third order harmonic distortion. I thought the distortion problem was associated solely with the tweeters?
Regards
IB
Every driver has their share of distortion, for a mid/bass driver it is usually higher the higher you go up in frequency and for a tweeter it is usually higher the lower you go in frequency, hence the crossover frequency is crucial for the sound. The main problem (as I understand it) Carlsson faced when choosing drivers / designing crossovers, was that the distortion of the mid/bass (sc165) gets kind of high towards 2khz (from below), and the distortion of the tweeters (mt20) also gets high towards 2khz (from above).

Now, the sc165 would've enjoyed a lower crossover frequency, and the mt20, a higher one (although the distortion in the mt20 @ 2khz is a much much bigger problem then the one in sc165).

The 'harsh' treble you hear however is obviously cause of the tweeters (and mostly because the crossover frequency is a bit too low for them), however, the sc165 cannot be split any higher then 2khz, so, hence it's split at 2khz. If the crossover frequency was closer to 3khz, then the tweeters wouldn't cause this much 'harsh' sounding treble.

I really really hope that grafpro is okey w/ this, but this is his measurement of distortion of a mt20 in good condition:
Image
Second harmonic is red, and third is blue, and as you can see, towards 2khz, the blue starts getting out of hand.

Stolen from: http://www.carlssonkult.se/kondiskanter.aspx

If you really wish to get to the bottom of this whole frequency response / distortion business in the Carlsson speakers, I really recommend you use google translate and read the corresponding articles there!!!!!

//Rob

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Re: OA-14: what should it sound like?

Post by Infinitely Baffled » Tue 16 Apr 2019, 00:30

Again, very helpful post. Thanks.
IB

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Re: OA-14: what should it sound like?

Post by momus » Tue 16 Apr 2019, 10:58

Well, I´ve heard more distorsion in my OD 11:s, compared to my OA 14. Although the elements was identical. I reckon this depends on the much bigger box on the OA 14:s. The bass also was fuller, but more noticeable in the kitchen (a room adjacent to the listening room). The comment on the bluetoothproblem was more a comment on my lack of golden ears. I didn't hear much difference between the T 22 tweeters and the old Peerless tweeter. But the T 22 is much more sturdier. I had to change the Peerlesstweeter three times in my OD 11:s.

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Re: OA-14: what should it sound like?

Post by therob » Tue 16 Apr 2019, 18:17

momus wrote:
Tue 16 Apr 2019, 10:58
Well, I´ve heard more distorsion in my OD 11:s, compared to my OA 14.
Hmm, might be because there's only one mt20 in od11 and so has been under a more heavy strain the 4 of them in oa14. But, that's just guesswork.

Also, I think (at least) one of the problems he is facing w/ the treble is the (assuming he has indeed switched out sc165 for b65oa-iv) ~2 db lower sensitivity of the b65oa-iv, which means that there is at least some imbalance between the frequency registers.

For fun, I took the T/S parameters from carlssoncult (those are measured on the drivers by grafpro), and as carefully as I could, inserted them in "Basta!".
For a 35 L cabinet tuned to 30hz (like its in oa14).

A normal room gain is applied and the red is satori, and the black is b65oa-iv, now neither of these is perfect, but there seems to be quite a resonance peak @ 30 hz w/ the b65oa-iv (now these are obviously not 100% accurate, but gives some general idea). The black plot at the bottom is the room effect/gain.
Attachments
b65oa_satori.png

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