Pretty diverse taste in music there!
In this corner of the world, I had a neighbour who likes music and systems very much drop by. He really liked the fact that even at low volume, the 15s can output bass that is balanced.
I tried adding some extra drivers I have to extend FR and give some air to those big 15s.
At the moment, I only have 3.3uf and 22uf caps... so, I tried the 3.3uf first.
I used the TC9s, but they were overwhelmed by the 95dB woofers...
Then, I added my W8-1772 on top, with the same cap. That was more balanced. But I think it would be best going a bit lower, with a 10uf cap... that's been ordered.
I wouldn't say the big 15s I have now are fast. They're fine doing simple bass lines, but if I try a full orchestra, it becomes a bit blurry.
I'll give a try with the 10uf caps on the 1772 to see if it helps, but I suspect the best match would be to cut the 15s at about 500Hz, and let the 1772 handle the rest.
Still, I was quite pleased that achieving this FR only needed 2 wide EQ bands. Probably an amp with bass/treble tones could achieve the same.
Starting to sound better.
In this corner of the world, I had a neighbour who likes music and systems very much drop by. He really liked the fact that even at low volume, the 15s can output bass that is balanced.
I tried adding some extra drivers I have to extend FR and give some air to those big 15s.
At the moment, I only have 3.3uf and 22uf caps... so, I tried the 3.3uf first.
I used the TC9s, but they were overwhelmed by the 95dB woofers...
Then, I added my W8-1772 on top, with the same cap. That was more balanced. But I think it would be best going a bit lower, with a 10uf cap... that's been ordered.
I wouldn't say the big 15s I have now are fast. They're fine doing simple bass lines, but if I try a full orchestra, it becomes a bit blurry.
I'll give a try with the 10uf caps on the 1772 to see if it helps, but I suspect the best match would be to cut the 15s at about 500Hz, and let the 1772 handle the rest.
Still, I was quite pleased that achieving this FR only needed 2 wide EQ bands. Probably an amp with bass/treble tones could achieve the same.
Starting to sound better.
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I measured my 15+ 12 inch set up yesterday. I also get a 80 Hz dip! The chokes I have might do better to be smaller. That isn't a cheap option so I might adapt a NAD 3020 I have as an active drive amp. The sound I get suggests this needs fixing. I suspect the 12 inch unit is a bit better to do the main work. I was inspired by some old Dynaco A25 I bought. I had a pair 42 years ago. The pair bought 2 years ago gave me ideas. In a large room ( village hall ) they really work. In a smaller room they sound less balanced.
Big drivers do move a lot of air.
The 80Hz dip, is it measured at the speaker or at the listening spot?
I've been looking at options to help my big 15s on top.
Found that the Beston ribbon RT002A-dipolar is available locally. It has good sensitivity, an opened back, and with a steep XO, I can reach to about 2500Hz. I'm tempted.
The 80Hz dip, is it measured at the speaker or at the listening spot?
I've been looking at options to help my big 15s on top.
Found that the Beston ribbon RT002A-dipolar is available locally. It has good sensitivity, an opened back, and with a steep XO, I can reach to about 2500Hz. I'm tempted.
The eyebrows are even worse.
Seriously though - you got to do what you got to do.
Nice result there Perceval. I'm sure it sound nice based on graphs. Maybe take that 150Hz to 1.5kHz shelf a bit?
I might have a bit of time tomorrow to work on it.
I'll might try the 22uf caps instead, and I'll work on that shelf.
The thing I get from my ultra cheap tweeter is a reasonable sound stage. This I don't really understand. My guess is the way I overlaped the 12Lta made a peak at 8 kHz and phase shift was a happy accident. Moving the approximate 6 kHz cross point to 8 kHz ruined this illusion, both first order. With a ribbon I doubt I would get this. The time I really heard this was on the sofa watching TV one night. Suddenly the left speaker that almost seemed silent 6 feet off axis had stereo imformation. I can only guess the overlap works down to 1 kHz somehow.
The bare 12Lta is not noticably bad at pretending to be full range. Where it misses out is the very narrow window above 2kHz. The very big surprise is how much better 78's sound with the added 15 inch bass and tweeter. It simply must be image width and that they need 50Hz bass. Even 1926 78's have this. If you as lucky as me the ladies here move inside the mono image.
https://www.youtube.com/watch?v=FA8zXI5KCDc
Even 1905 is worth a try.
https://www.youtube.com/watch?v=fb2s9OLEjfg
The bare 12Lta is not noticably bad at pretending to be full range. Where it misses out is the very narrow window above 2kHz. The very big surprise is how much better 78's sound with the added 15 inch bass and tweeter. It simply must be image width and that they need 50Hz bass. Even 1926 78's have this. If you as lucky as me the ladies here move inside the mono image.
https://www.youtube.com/watch?v=FA8zXI5KCDc
Even 1905 is worth a try.
https://www.youtube.com/watch?v=fb2s9OLEjfg
The ones I bought for another project was great. It is more reputation than fact that ribbons beam. Some are very good. These have very little low resonance at the lowest usable frequency so can be exploited to the maximum in a domestic speaker.
SWANS-Speaker: SWANS Ribbon Tweeter
SWANS-Speaker: SWANS Ribbon Tweeter
For my speakers these might work. I could use 1st order if 6 kHz as at 3 kHz output would be usefully reduced to prevent damage. Looking at the polar graph the results look good. It might need an amplifer for ideal matching. I always fancied I could build a very nice SE EL84 triode amp where the transformer could be smaller than usual. 1 watt should be plenty. If the grid resistance was 470K the preamp wouldn't even know it was there. I am not automatically a valve lover. For this use it would be ideal. I used the Swan RT 1.3 in my previous project. The DT74/8 was just to get a feel of the possible. I was concerned that the baffle was too wide to work. Surprisingly it works very well. I have considered having the tweeter coaxial with the 12 LTa. It would be easy to try and might work.
http://www.parts-express.com/pedocs/specs/297-400-hi-vi-rt1c-a-specifications-44319.pdf
http://www.parts-express.com/pedocs/specs/297-400-hi-vi-rt1c-a-specifications-44319.pdf
Forgot to say... that graph is with a 22uf cap... so moved the XO much lower... and I like it.
I gave a link of a guy saying domes are better than ribbons on youTube or so it seemed. Reading Swans PDF they feel vertical restriction is a good idea. Yes and no. What a friend does is uses a cheap piezo behind the speaker throwing off the back wall. It certainly works. Interestingly it is best when no crossover in this use. It seems to help integration of the Fostex 4 inch and 12 inch Leak speaker. It also gives image lift.
My 15 inch bass chokes are 7 mH. The unit approximates to 5R7. The output dips at 80 Hz measured at the speaker. Has anyone tried shunting an inductor with a resistor to reduce it's effect? These chokes were from another project. They have very high saturation levels so nice to have. They are in M6 metal.
Domes tend to have more power handling towards the bottom of their range, some of them reaching down to 1kHz with decent power handling. Ribbons tend to have very little excursion available, which limits their mechanical power handling in the kHz range. If you use a really long ribbon, you get more radiating area which makes up for the lack of excursion. You do then have to consider VHF line array effects, though, which is a whole 'nuther can of worms.
A ribbon will often force the use of a small-format midrange driver (3-4") to get the crossover up at 5kHz or so, and then you'll need a bass driver. A decent dome will do 2kHz-20kHz+ just fine, even at loud levels, so you can cross to a midbass driver in the 6-8" range and get enough low end for most people.
Chris
A ribbon will often force the use of a small-format midrange driver (3-4") to get the crossover up at 5kHz or so, and then you'll need a bass driver. A decent dome will do 2kHz-20kHz+ just fine, even at loud levels, so you can cross to a midbass driver in the 6-8" range and get enough low end for most people.
Chris
Swan say 2nd order to use 3 kHz. Saying 6 kHz if 1 st order backs up what you say Chris. The Swan might be a bit better than a true ribbon as they should be a bit tougher and also show no resonance at 3 kHz. They do dip below that. I was told if a crossover could be set above 7 kHz we might do better than usual in terms of listening fatigue. This is fine if the listening window is reasonable.With my expeimental use of the DT74/8 I got exactly what I hoped for. I am still surprised I did. It must be pure luck. What might be happening is I have created a hump in the output that is high enough up to sound OK. Either side of the hump are nice benefits.
Ok,
I've kinda given up on ribbon tweeters now. I don't think they will do what I want to do here.
Tried a few different things tonight and... I got somewhere nice!
the 22uf cap is still on the W8-1772, but I can't find inductors over here! They sell capacitors, but not inductors.... go figure! I'll have to get a shipment from parts-express. So, first order, it is!
Then, I used JRiver to add a first order (-6dB) on the 15" woofer (and I also had to reverse polarity on the woofer to match).
That gave me a XO at about 570Hz, woofer is the blue line, 1772 red. A few EQ filters later, I get something I start to like, as the purple line.
Finally, I fire up DRCDesigner, using their soft preset, and a -3dB from 1kHz to 20kHz slope. That gives me the green line and a very nice listening session.
Impulse response was also improved by DRC (from purple to green), later, I will start to play with gmad's custom scripts for DRC.
That's also the best spectrogram I've had in a long time!
I've kinda given up on ribbon tweeters now. I don't think they will do what I want to do here.
Tried a few different things tonight and... I got somewhere nice!
the 22uf cap is still on the W8-1772, but I can't find inductors over here! They sell capacitors, but not inductors.... go figure! I'll have to get a shipment from parts-express. So, first order, it is!
Then, I used JRiver to add a first order (-6dB) on the 15" woofer (and I also had to reverse polarity on the woofer to match).
That gave me a XO at about 570Hz, woofer is the blue line, 1772 red. A few EQ filters later, I get something I start to like, as the purple line.
Finally, I fire up DRCDesigner, using their soft preset, and a -3dB from 1kHz to 20kHz slope. That gives me the green line and a very nice listening session.
Impulse response was also improved by DRC (from purple to green), later, I will start to play with gmad's custom scripts for DRC.
That's also the best spectrogram I've had in a long time!
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