[-Richard-]

Hi painkiller ~

I am also very interested in your experiences with your new, quite beautiful in their own right, TT drivers.

There is something very deeply satisfying in working with drivers that are actually "designed" to be beautiful.
I can think of Corvette red and 50's style modernity... which thrilled us as young adults... in many cases still does.

Please keep us posted as you become familiar with what you are hearing.

Dmason has been suggesting for quite some time that Hemp married to an Alnico magnet can bring us the closest yet to OB's potential for that magic we all crave. Congratulations on your new arrivals.

Warmest Regards ~ Richard

[painkiller]

New pics here: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1481

I made the simplest cheapes baffle I could find, from 22mm MDF. The center of the drivers are placed 12 inches above the floor in a 750x900mm wide board. The drivers are mounted 8mm into the back of the board, with a short "waveguide" on the front side. Nice WAF project. 

Took a rough initial measurement as you can see in the gallery. This is in room response, pretty close to a side wall, so take it with a big pinch of salt. The response drops off quickly at 100Hz and 5Khz. I can't see any advantage in comparison to the regular version, so I guess my advice would be to buy the standard treated cone instead of the double treated one. Or maybe the 10" instead, as it seems unlikely to use this driver without bass augmentation anyway.

I can't use these baffles in the long run. They take up too much space, and I need room for a bass driver. So next step is to make a 1000x50mm baffle and get a 15" woofer.

Fortunately my current speakers use a horn loaded tweeter with phase plug, so I just hooked it up with a 4,7uF series capacitor (crossed around 5500Hz?) and it actually blends in pretty nicely. My speakers are biwireable, so I also use the 6,5" woofers for bass below 100Hz just to get an idea of how it could sound in real life.

To say the least, this setup is all wrong. Crossover points are hopeless. Frequency response must be pretty bad, and theres a noticable emphasis male voices and shh sounds, and little bass. They are extremely loud, and I have no idea how I'm supposed to break in the drivers. Guess I'll have to massage them manually.  aa

Despite all this, there are some moments when everything sounds really good. Solo instruments like piano, guitar and female voices sound more lifelike than I'm used to. But on more complex cd's it gets tiresome, and the sound is way too bright and distorted. Some times the drivers are really detailed and other times it's just a mess. So, mixed results in the beginning, which is not exactly a surprise.

But I do feel that these drivers have a lot of potential. I need to break them in for a few hundred hours, and get a woofer, and then we can see.

[painkiller]

By the way, I'll be happy to take any advice regarding, baffle shape, driver mounting, matching drivers, crossovers etc.

Are there any theories on how the different drivers should be mounted for optimal time alignment? 

[nodiak]

I haven't reread the thread so may have missed info about your room. It looks ~200 ft2 or less? Untreated, reflective  = slap echoes etc., speakers ~ close to walls = bass lift. The graph does have peaks and dips but overall those could be room, and no wild peaks near upper end rolloff.
Regarding sound quality of hemps, seems they'd mellow out a little from that sharp sound, but I'd seriously consider room treatment to handle reflections and a narrow baffle like Jon Ver Halens. Your room might bring the bass lower than the 60 hz he gets. Otherwise a seperate ob sub for the bottom octave or two, and smaller ob mains that only need to reach 70-100hz to mate with sub. OB sub along side wall, small ob mains in 15" or narrower baffles. Your 12" or a 10" with fr or tweeter above is possible. This is the track I am on with narrow room (12') and it is workable. GR Research OB sub/s, or plate amp and 15" along side wall (flat baffle against wall). Once the sub is dialed in to room, the main ob's are smaller and simpler.
Don 

[Graham Maynard]

Hi Painkiller,

The larger the cone the more the beam inducing interference between concentric radiation at some radius with respect to that from the centre.

Try two soft foam fingers vertically close to the cone to disperse some of the centre radiation, and damp radial wave interference.

http://server6.theimagehosting.com/image.php?img=Fingers.a9d.jpg

Cheers ....... Graham.

[dewar]

1000x50mm baffle covered in 3/8" wool felt. And a 15" Augie, thats all I can swear by. Looking forward to your impressions.

cheers

B.

[painkiller]

Well, I've been doing some listening during the past days, and I'm beginning to suspect that the H1EDD version with "more highs" doesn't have extended frequency response as I hoped, but rather a more uneven response with emphasis on the 2kHz-5kHz range which is quite annoying.

But after playing around with EQ I got a really nice tonality. It required pretty hard EQ below 100 Hz to get any bass response. And the 2kHz-5kHz region is lowered a few dB to get rid of that annoying shouting sound. I have to say I'm really impressed. Especially the the speed and low level detail is extremely good. Imaging is very good, even in this wide baffle. I do feel that these drivers have great potential, and really want to build a 3 way around the TT alnico. But since these 12" H1EDD drivers were not exactly what I hoped for, I'd rather get the standard 10" drivers. The lower SPL will make tweeter and woofer choice and integration easier, and hopefully I can cross them over higher than 5kHz.

It was a leap of faith buying these drivers, and I see now that I need to explore further. I wouldn't want to compromise, so I want to try the 10" TT drivers for comparison and find the best solution.

[ttan98]

Painkiller,

Do you think the 10" TT can be used a s mid and lower mid range, hence the high is covered by a compression driver/ribbon and bass covered by AE bass driver.

What freq range can a 10" TT cover?
Is this driver capable of handling all kind of music in this freq range, eg vocal, jazz and rock?
(Full Ranger  like fostex can only handle jazz and vocal well, not good in rock and heavy metal)
Your opinion please.

[painkiller]

I'd also like to know what frequency range the 10" can cover, and that's why I'm planning on buying it.  aa

I'd say that both the 12" and 10" are only midrange drivers. You'll need a tweeter and a bass driver with both of them. The bass driver will need to cover the lower 10-200Hz as a minimum. Tweeter must be crossed around 5500 for the 12" and hopefully a bit higher with the 10".

This driver can be used with any type of music, but you'll either need well integrated bass drivers, or heavy EQ. The emphasis on the vocal frequency range makes almost any type of music unbearable. But when the frequency response is flattened out all sorts of music is just wonderful to listen to. It works great with most genres of music, and simply amazing with the rest.

[nullspace]

But after playing around with EQ I got a really nice tonality. It required pretty hard EQ below 100 Hz to get any bass response.

Hi Painkiller --

The lack of usuable bass is the logical outcome of using a driver with a resonant frequency around 80hz -- it's not designed to produce <100hz. I would be cautious about EQ'ing up the low end as the driver will only have a mm or two of linear xmax.

Regards,
John

[scorpion]

painkiller,

Looks as if you are in need for just that ! Joke aside, I suppose the units still might change a bit in response during burn in. Then it is time to make a decision. But I agree with nullspace you can't expect these to deliver thundering low-bass. John Ver Halen of Lowther America added a sub for the lowest frequencies. Lynn Olson's freq response is so flat as to be unbelievable in the lower midrange, but mind you also his graph shows a rising response between 1.5 and 5 kHz which he thought should be EQed away and perhaps this feature is amplified in your version of the speaker. Is off-axis response also offensive in this range ?

/Erling

[dewar]

I had feeling the brighter alnico might have been more tipped up rather than more extended. pitty. Appreciate you guys going where no man has gone with these. If I had any more disposable income and shipping to Oz wasnt so damn expensive I would be happy to test pilot them myself.

One concern I have is comb filtering when adding a tweeter at say 8k. I'm not too clued up on this stuff but I do remember back on the dark star thread last year raising this point after having seen some FR graphs by Danie Richie and it looked pretty scary. I ended up going with a rear mounted tweeter on my B200's for this reason. I've also just read somewhere on this forum someone citing the importance of having the tweeters exactly time aligned with the woofer cone to avoid this comb filtering, and how even small differences in recess will make big differences at the listening seat. If this is true, which seems to imply that time alignment is more important with a 8k crossover than with a typical 2.5k crossover(?), would this not mean that ones head would need to be at a height exactly between the two drivers, and that any movement up or down in the listening position would have the same detrimental effect as having the divers not time aligned in the baffle. Or is my thinking a bit off the mark here?

Thanks for the input guys

Bevan

[Graham Maynard]

Hi Bevan,

I have had much improved HF from an unmodded B200 by using a 'time aligned' hornless APT50 with circa 470nF series feed and 22 ohms damping across the APT voice coil. 
Time alignment being the physical alignment of the front circular casting aperture of the APT level with the front-most cast leading edge of the B200;  this places their centre-caps at the same distance from a listeners ear.  The APT and B200 edges can be touching to minimise distance, with the APT magnet partly tucked in behind the B200 cone.

Your comment about combing must be valid and measurable, yet this is not something which is troublesome;  probably due to the limited frequency range at which the drivers had identical overlapping output, unlike the broad overlap which arises with line sources etc.

I read many times that an additional tweeter degrades the B200 performance.  Few tweeters match the B200 for natural sensitivity, and a dome type plonked on the same baffle simply cannot be made to sound natural unless its HF waveform is delayed in order to achieve time alignment.  As for crossovers at 2.5kHz providing less 'combing', this also must be so, but I would not want a crossover there anyway.

The APT50 might well be an inexpensive match for the TT running wideband too.  Say with a 1uF series 'C' plus a 12 to 15 ohm parallel damping resistor, and with the front of the magnet approximately level with the rear-most part of dust-cap to cone join.  Foam fingers to disperse the TT HF peak just before its natual crossoverless roll-off might finish this off nicely.

Cheers ......... Graham.

[painkiller]

Some interresting thoughts and ideas around here. All inputs are highly appreciated.

I can't seem to get my measurements together. The results don't seem to make any sense. Don't know if it's the measuring mic, or if it's just me who haven't figured out the software.  Appologies to those who expected relevant measurements. I guess my subjective impressions might not be of any use to others than me.

It's obvious though that the midrange peak is way more than 5dB in this case. More like 10dB. This makes med wonder how the untreated cone with "less highs" behaves. Perhaps the untreated cone gives a flatter frequency response? I saw Lynn Olson's idea of having a bass driver run all up to 800Hz, to avoid the heavy EQing, but when the drivers are so efficient I don't know of a bass driver that could even out such wild rise in the midrange..

It seems like it's pretty easy to sell these drivers over here, as they are not readily available. It's no problem to buy and sell TT drivers with almost no financial loss.  Makes it even more tempting to try out all different TT drivers.  aa


Graham: Thanks for the tweeter tip. I'll make sure to put it on my wishlist.

[painkiller]

Try two soft foam fingers vertically close to the cone to disperse some of the centre radiation, and damp radial wave interference.

Thanks for this great tip. It doesn't look good, but it certainly works! I tried a simpler version with a rolled up towel, and it seemed to remove most of the annoying "shouting" sound. It doesn't seem to have any negative effects either. I actually prefer it over the digital EQ.

But now it's time to move on with my experiments and on to a new TT driver. Exciting times ahead.  aa

[Graham Maynard]

Hi painkiller.

So glad you found this method helpful;  it could be more widely applied in front of wide-range drivers. 
Once 'shoutiness' is overcome the real advantages of crossoverless non-EQ drive through the full voice range of frequencies can be appreciated.

It is possible to make a cloth absorber/diffuser look more acceptable by loosely wrapping it around a small screwdriver handle with nice chrome shaft, and then mounting to the front baffle via the shaft.
Or making a feature of chrome rod or tubing (clothes rail) on the cabinet front with cloth over the end in front of the driver.

Cheers ........... Graham.

[scorpion]

I put a simulation of The Tone Tubby 10" on OB in the 'B200 and Eminence Alpha 15A report'

/Erling

[painkiller]

I've now had a chance to audition the 15" Super Boy bass driver in a 50cm wide 100cm high baffle, mounted 1" off the floor. To say the least this is not an OB bass driver, but it's a hell of a midrange. 

Subjectively it seems to be really flat from 100-150Hz and up to 5kHz, befor it starts dropping quickly. With EQ you can actually make it sound quite good up to 7kHz. It sounds much better that the double dipped 12" Alnicos I've now managed to sell. The sound is quite similar, but without the annoying midrange peak. And, my god, this driver is powerful! SPL close to 100dB. I guess one could couple it with a tweeter around 5kHz and a woofer under 100Hz and get a very good result. Problem is how to get a subwoofer to match a 100dB midrange.

The build quality of the Super Boy is much better than the red Alnico's by the way. The frame is sturdier, and the surround of the cone seems less rigid. I guess the cone is untreated also. But there's no way to make this driver produce bass... unless you're willing to make a 500 litre vented enclosure. 

Anyway. My best tip is to try and get an untreated version of the 10" 16 ohm driver, Eminence 15A for bass (which seems like the only sensible bass driver for OB), and a tweeter crossed high. This version of the TT is less efficient, so it would be interresting to combine with a good textile dome. The peerless top line looks really good with an SPL of more than 94dB above 7kHz. http://www.mamut.net/dynabel/subdet653.htm

[painkiller]

I put a simulation of The Tone Tubby 10" on OB in the 'B200 and Eminence Alpha 15A report'

Looks really impressive! I think it could be an ultimate OB midrange.

[scorpion]

So I think too. Without the baffle influence it would go ruler straight if it corresponds to the published specifications. Also we can rely on Dan Mason's appreciation of it.

Painkiller, if you really will go for the 10" TT I think I will renew Florian's threat that he and I would come to visit and listen, properly equipped !

In the meantime why not put up a new measurement of your 12" now that you have played with them for a good while, that would be interesting. 

/Erling