It's really great that we have at least one who is able to read measurements objectively - also beyond own experience, and see what speaker is globally the best, and best for each listener, conditions and setup.
Vertical lobing can be handled and made working to an advantage. Carefully controlling the phase and spacing between drivers. Only issue would be the smaller dip of 3dB in the power response with higher frequency in phase crossovers. The audibility of it when done right is hard to prove given normally furnished listening rooms with carpets.
I would think the audibility of crossovers has to do with mismatched phase responses and/or mismatched dispersion patterns or thermal/linearity issues. Crossovers changing q with signal. It's not easy.
There's also the ability to tweak the vertical response a bit to aid the illusion of the height of the soundstage not locked at the height of the speakers but beyond i.e. when listening standing up. Not possible with coaxial drivers thou. In this case crossing over at around 3k around where the ears height hearing is affected can be pretty suitable.
You're being defensive😉
We would all be very happy to agree on everything, but it's not gonna
happen, not in this universe. Later for sure.
It is fun to read all these posts and see how people function and what
their priorities are.
What Earl is saying about speakers, makes sense and his products are
well thought out for the desired group of people, IMO.
If I had more funds, time, space and blessing of my family, I would have
built new projects with horns and guides, just for fun and some more
enlightenment.
Last edited:
I'll assume that you have fairly good loudspeakers. Put a blanket over it. That is the lack of deffinition and that is how 15" woofer sounds from 400-1000Hz in regard to 6" dedicated midrange at the same area.
Any clearer ? 🙂
Well yes, i defend my oppinion formed on experience that i have with large format two way - particularly two types of Econowave loudspeakers that i made (with 12" woofers and JBL PT waveguides) which was just to see what's all the fuss about and few days later i was hooked 🙂 .... and 15" woofer with 18" waveguide that i made later on. 12" bassmid can play pretty high and nice if Mms isn't high and Le is low. I must say that biggest Mms in 12" bassmid that i heard is Beyma 12LW30 with Mms of 77gr but i auditioned it too short to bring any valid conclusions about the sound. The owner on the other hand always said that lower midrange that Beyma is playing lacks deffinition - as was my impression with 15" woofer (Mms of 107). 12" bassmids i used are Deltalite II 2512 and Sonido SCW300 (Mms under 40gr and Le under 0.8mH).
Can't argue with that. I've read his posts and been reading his papers lots of times. It makes sence most of the time.
The thing i don't agree is that Earl thinks that his set of compromises are the least amount of compromises (if we agree that every loudspeaker is compromised in some way). The thing i can never agree on is that 15" woofer will sound the same (or better) than 6" dedicated midrange from >400Hz and that is precisely what he tries to persuade us.
Other than that there is not much not to agree on with Earl.
Last edited:
I talked with him but he was not able to give me a competitive deal. I also did not find their performance up to B&C.
Not just one, JBL's entire engineering staff (past and present) would make the same claim. It's the golden ears who object. Funny how that works out.
C'mon then. I want to see measurements of spaciousness and coloration... and not to forget imaging 😉
Then i'll list what are the differences between 15" woofer and 6" midrange that makes one better than another for playing frequencies 400Hz and up.
Last edited:
The reason I try to avoid xover points in the upper midrange is because that's the main area of frequency where we can decipher the stereo effect. From about 1.5kHZ - 6kHZ we sense image location by amplitude comparisons left to right and vice versa. A crossover in this range can cause amplitude variations between the two speakers in several ways. Below about 1.5kHZ, we would decipher image location primarily by timing comparisons if inter-aural crosstalk didn't screw that up.
I've been using the Peerless TG and/or Vifa TC 3 inch full range drivers (very similar) to handle from 500HZ - 7kHZ. In my latest system(s). I have a kevlar 8 inch woofer in a sealed box actively EQ'd for 30HZ - 500HZ, and I would use a 1.5 inch Fountek ribbon, or a model ND20FB-4 Dayton 3/4 inch dome for 7kHZ - 20kHZ+. the Dayton may actually sound better than the ribbon because it's flange is almost non-existent, so it could butt up right next to the 3 inch midrange driver (ideally right above it), and Zaph says those are VERY flat from about 5kHZ thru 20kHZ (and he actually uses them in one of his fancier systems).
For woofers, I'd recommend looking at the Peerless 6.5 inch and 8 inch Nomex cone drivers. I use the 6.5's in one system and am VERY impressed.
Although I prefer 4th order active crossovers and active woofer EQ, passive crossovers would work OK too. The only shortcoming of significance in my mind is the fact the the Peerless TG driver is only 85dB sensitivity, which means using a passive crossover would require a roughly 3dB attenuation of the 8 inch woofer by the time it gets up to 500HZ. An attenuator means less damping by the poweramp, which could be an issue. The coils are a little expensive if you want to do a slight bit of passive EQ there, at which point I decided to go active. Active crossovers are so much easier than passives to get right.
The Vifa TC 3 inch driver is arguably virtually just as good as the Peerless TG driver (both brands are now owned by the same company, Tympani, which also owns Scanspeak if I remember correctly), but has a black cone instead of light grey in the TG driver. But these 3 inchers are actually very nice, with the vented pole piece, well vented spider, shorted turn on pole piece, rubber suspension, Good Xmax but not so good that the surround suspension causes significant "cavity effect", and one of the flatter frequency responses. Roger Russel, formerly of McIntosh, chose the Peerless TG driver for his $19K line array system, citing that it had the most fixable frequency response of the bunch.
I've been using the Peerless TG and/or Vifa TC 3 inch full range drivers (very similar) to handle from 500HZ - 7kHZ. In my latest system(s). I have a kevlar 8 inch woofer in a sealed box actively EQ'd for 30HZ - 500HZ, and I would use a 1.5 inch Fountek ribbon, or a model ND20FB-4 Dayton 3/4 inch dome for 7kHZ - 20kHZ+. the Dayton may actually sound better than the ribbon because it's flange is almost non-existent, so it could butt up right next to the 3 inch midrange driver (ideally right above it), and Zaph says those are VERY flat from about 5kHZ thru 20kHZ (and he actually uses them in one of his fancier systems).
For woofers, I'd recommend looking at the Peerless 6.5 inch and 8 inch Nomex cone drivers. I use the 6.5's in one system and am VERY impressed.
Although I prefer 4th order active crossovers and active woofer EQ, passive crossovers would work OK too. The only shortcoming of significance in my mind is the fact the the Peerless TG driver is only 85dB sensitivity, which means using a passive crossover would require a roughly 3dB attenuation of the 8 inch woofer by the time it gets up to 500HZ. An attenuator means less damping by the poweramp, which could be an issue. The coils are a little expensive if you want to do a slight bit of passive EQ there, at which point I decided to go active. Active crossovers are so much easier than passives to get right.
The Vifa TC 3 inch driver is arguably virtually just as good as the Peerless TG driver (both brands are now owned by the same company, Tympani, which also owns Scanspeak if I remember correctly), but has a black cone instead of light grey in the TG driver. But these 3 inchers are actually very nice, with the vented pole piece, well vented spider, shorted turn on pole piece, rubber suspension, Good Xmax but not so good that the surround suspension causes significant "cavity effect", and one of the flatter frequency responses. Roger Russel, formerly of McIntosh, chose the Peerless TG driver for his $19K line array system, citing that it had the most fixable frequency response of the bunch.
Last edited:
Just go with the biggest wave guide you can imo. Even if it's just 6" that's still miles better than a naked dome.
Maybe you can't tell but i'm sure that others can. There is an emoticon at the end of my post so that would suffice. It wasn't adressed to you anyway.
But don't you worry about who'll think i'm serious and who will not...
You should worry about those coloration, imaging and spaciousness measurements you can make. Show them to us please.
Thanks in advance.
Last edited:
That's interesting. Almost every measurement I've seen of the TD range beats every measurement I've ever seen for any B&C drivers, both in terms of FR linearity and the motors non linear distortion.
Maybe the measurements I've seen are of the wrong B&C drivers. But most of the ones I've seen have been with drivers that contain shorting rings.
The TD12M is the 12" AE driver that anyone would recommend for a mid/bass and those measure like this.
Extremely linear motor and a very well designed cone. All the B&C drivers that the same chap measured are quite a bit worse in every measurement that he does.
Hi Bob,
No problem of directivity in the high with the 3"... or do you take advantage of this attenuation in the critic M-F range around 3 Khz ?
which slope do you use for the LPF of the 8" woofer at 500 hz ? Because of the break mode on the cone :no regrets e.g. to use a specific mid-bass like a 6" in sealed cabinet to match with your design, let say between 80-100 to 500 ? If you use minimum 4 order and EQ ?
@ Fifth element : what drivers and XO do you use for your speakers please: that's to help me to understand the dialogs better ?
I'm actually using the B&W FST drive unit that Zaph measured as the mid range in my loudspeakers. I originally had it combined with a 6.5" wave-guide and crossed at 2.2kHz and this sounded excellent, miles better than anything without a wave guide. Now I'm trying the FST without the phase plug and using a small tweeter mounted coaxially. I'm having rather good success with that. The FST surround on the mid range works very well as the edge termination of the wave guide and measures well.
I have a rather small room (~3.5x4 meters) and cannot have large loudspeakers in them. I also do a lot of near field listening. Having the tweeter mounted coaxially makes quite an improvement to the sound near field, vs using the separate wave guide and even when I sitting far field I am still only just over 2 meters away from the loudspeakers. I am sure this makes a considerable difference to the perceived sound quality as I am never truly what some people would consider properly far field.
The crossover is my own design, it's a DSP from Analog Devices + ES9018 in multichannel mode. The coax uses a 2.2kHz xover too. I originally took a load of off axis measurements and made sonograms of the FST and wave guide and to get a good directivity match they could be crossed roughly between 2 and 2.5kHz.
I have a rather small room (~3.5x4 meters) and cannot have large loudspeakers in them. I also do a lot of near field listening. Having the tweeter mounted coaxially makes quite an improvement to the sound near field, vs using the separate wave guide and even when I sitting far field I am still only just over 2 meters away from the loudspeakers. I am sure this makes a considerable difference to the perceived sound quality as I am never truly what some people would consider properly far field.
The crossover is my own design, it's a DSP from Analog Devices + ES9018 in multichannel mode. The coax uses a 2.2kHz xover too. I originally took a load of off axis measurements and made sonograms of the FST and wave guide and to get a good directivity match they could be crossed roughly between 2 and 2.5kHz.
For one thing the 12" B&C driver Earl measured has a 4"x1" VC.
I am sure AE motor structure can maintain a low enough thermal compression with its tiny VC by efficiently exhausting heat, but that does nothing for "instantaneous" thermal compression (distortion).
I don't think thermal compression is going to be any issue whatsoever in a domestic environment with a 97dB speaker.
- Status
- Not open for further replies.