I ordered a 15" driver locally. There was mention of 35Hz to 15kHz on the website.
Looked interesting enough, and not too expensive.
Got them home and couldn't resist... I put some baffles together with some scrap wood I had, bottom baffle withe the 15" drivers, added wings to the sides.
Top "sticks" were for mounting a 3" fullrange driver, like the TC9FD in OB as well... but I might just get a tweeter instead and just add a cap around 8kHz.
Those 15" do indeed go at least past 10kHz, by ear. Had no time to measure... hopefully tomorrow.
But, the sweet spot is quite narrow, due to beaming, which was expected from the 15". even with the whizzer.
Still... they sounds quite balanced and will probably need very little work to sound great.
Never had a 15" fullrange before... kinda cool!
Looked interesting enough, and not too expensive.
Got them home and couldn't resist... I put some baffles together with some scrap wood I had, bottom baffle withe the 15" drivers, added wings to the sides.
Top "sticks" were for mounting a 3" fullrange driver, like the TC9FD in OB as well... but I might just get a tweeter instead and just add a cap around 8kHz.
Those 15" do indeed go at least past 10kHz, by ear. Had no time to measure... hopefully tomorrow.
But, the sweet spot is quite narrow, due to beaming, which was expected from the 15". even with the whizzer.
Still... they sounds quite balanced and will probably need very little work to sound great.
Never had a 15" fullrange before... kinda cool!
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Can you share with us which 15" full range speaker you bought?
And how do you go about measuring the frequency range?
Thanks.
And how do you go about measuring the frequency range?
Thanks.
I bought it in Taiwan, made there as well. I'm sure the company wouldn't mind shipping abroad, they were very helpful and fast.
With REW and a microphone.
https://www.roomeqwizard.com/
Do you have a manufacturer name and model number? Or... a link to the website you mentioned in your original post.
Got a pic of it?
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Here's a translation of the page you can find some info on the driver. So far, the T/S specs match what I have closely enough... a welcomed sight in a land of specifications "groomed" by the marketing department.
https://translate.google.com/transl...en.com.tw/item/show?21608878594198&edit-text=
NT$2600 is about $84 in the US.
https://translate.google.com/transl...en.com.tw/item/show?21608878594198&edit-text=
NT$2600 is about $84 in the US.
15inchers have been moved to the living room for an hour, and so far, no mention about them from the wife.... 
I grabbed the mic for a quick FR test.
Pleasantly surprised.
Red is the FR as is, mounted on the OB.
Gold is with 2 bands of EQ, one at 80Hz +6dB, the other at 6.5kHz +4dB.
I'm going to leave the top alone, and add the TC9 on top, crossing at about 2kHz. That big 15 inch driver struggles a little over there, especially beaming, but with something like the TC9 helping on top, should be fine. I'll probably just put a single cap to see how it goes.
Pleasantly surprised.
Red is the FR as is, mounted on the OB.
Gold is with 2 bands of EQ, one at 80Hz +6dB, the other at 6.5kHz +4dB.
I'm going to leave the top alone, and add the TC9 on top, crossing at about 2kHz. That big 15 inch driver struggles a little over there, especially beaming, but with something like the TC9 helping on top, should be fine. I'll probably just put a single cap to see how it goes.
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Not even "the eye?" 😀
Not even "the eye" !!
After 5 hours, I couldn't stand the unresolved issue, soooooo when the wife walked by me, I mentioned if she had seen the change of speakers in the living room.
She said, "yeah".
So, I say, "and?"
She said she's not so surprised anymore. She's getting used to all my crazy projects, and, even though these things are quite bigger that the last set, she's ok with them. She was a little concerned about the looks... I told her these are just mock ups, and when I like where it's going, I'll make nicer baffles.
So, all in all... pretty good!
No killing look, no complaints.
I got the best wife! 🙂
Now, to add some higher frequencies to the mix!
After 5 hours, I couldn't stand the unresolved issue, soooooo when the wife walked by me, I mentioned if she had seen the change of speakers in the living room.
She said, "yeah".
So, I say, "and?"
She said she's not so surprised anymore. She's getting used to all my crazy projects, and, even though these things are quite bigger that the last set, she's ok with them. She was a little concerned about the looks... I told her these are just mock ups, and when I like where it's going, I'll make nicer baffles.
So, all in all... pretty good!
No killing look, no complaints.
I got the best wife! 🙂
Now, to add some higher frequencies to the mix!
Looks really good considering how it shouldn't. I use a 12 Lta which is not a lot different and a 15 inch helper. I now have a DT74/8 tweeter crossing at 6 kHz first order in phase ( that is + to + via the cap, tried both ). Since I fitted a phase plug it all seems to come together, I use a small paint roller for that. The 12 Lta has no passive filtering. The 15 inch comes in below 250 Hz via a big pair of chokes I happen to have. The big deal is the tweeter and 15 inch bass seem to do nothing until removed. The bigger deal is the tweeter for reasons I only just understand cures the narrow window. I think I got very lucky with my ideas as the neutrality is not bad. The bigger lucky part is some very simple bass and treble boost completes the design. I would imagine even a NAD 3020 would be OK with this idea as 100 Hz and 10 kHz EQ seems OK. The DT74 was the only tweeter that easilly could work, the very low price is a bonus. You might try one as it will point the way. I only thought to use it for a day or two, that is over a year now. What I don't really understand is how it can do so much when the baffle should kill any chance. I got very lucky. Could be crossing so high helps the tweeter do what it shouldn't.The energy it sees is lower than typical when 3 kHz crossed.
I have some piezo horns that although interesting didn't do what I wanted. I did fit them with a crossover if wondering ( shunt resistor and series capacitor ). Firing against the back wall wasn't bad with them. If I do use them it might be at 15 kHz. I have heard crossed over piezo's sound very open and nice. Not this time. DQ10 used them.
https://www.monacor.com/en-gb/monac...peaker-technology/miniature-speakers/dt-74-8/
My best version on a 4 x 2 foot x 2 inch baffle was on polystyrene. I never worked out a good way to make it practical. I now use 50/50 ply and MDF. The polystyrene was less coloured yet had great bass. I get when EQ'ed 40 Hz flat and 30 Hz - 12 dB.
I have some piezo horns that although interesting didn't do what I wanted. I did fit them with a crossover if wondering ( shunt resistor and series capacitor ). Firing against the back wall wasn't bad with them. If I do use them it might be at 15 kHz. I have heard crossed over piezo's sound very open and nice. Not this time. DQ10 used them.
https://www.monacor.com/en-gb/monac...peaker-technology/miniature-speakers/dt-74-8/
My best version on a 4 x 2 foot x 2 inch baffle was on polystyrene. I never worked out a good way to make it practical. I now use 50/50 ply and MDF. The polystyrene was less coloured yet had great bass. I get when EQ'ed 40 Hz flat and 30 Hz - 12 dB.
BTW I crossed at 8kHz. It was hopeless. It seems the overlaps work for me.
The bass unit has a Qts of 1.2 measured. It is a spare part for something nasty. It is very well made.
QTX 902.539 42Hz to 5kHz Chassis Replacement Drivers For QT Series Speakers | eBay
The bass unit has a Qts of 1.2 measured. It is a spare part for something nasty. It is very well made.
QTX 902.539 42Hz to 5kHz Chassis Replacement Drivers For QT Series Speakers | eBay
Don't fail to use The Wife's ear as part of your evaluation process.
Isn't a resistor in series necessary with a piezo xo?
Isn't a resistor in series necessary with a piezo xo?
The wife is my friend Colleen. She has interesting hearing. The phase plug made from a paint roller works well. Many attempts to do better failed. The one that didn't fail was some very cheap hair fixers I think called scrunchies used to do pigtails ( borrowed from my daughter ). What these show is echo in the recordings which has been added and similar nice quirkes. You have to try them at various positions to get the best ( paralell with the Wizzer is not a bad place to start ). My sound engineer friend really liked them, Colleen not. I sort of understand why she likes what she does. It is hearing the mix in a typical way, only better. I have to say her hearing is a bit like her taste in wine. She likes all the typical white wines and mostly has a similar taste to me. She doesn't much like Riesling as too fruity! That's bonkers. I know what it is, sweet Riesling can not be forgiven. The Beatles didn't like to hear the mixes. The Beatles Love album on LP is all about showing the mixes. Highly recomended for speaker listening tests. Cheapest turntable a Lenco GL 75 I would say. If you do get the LP you can do pick up arm mass experiments if voice quality is your thing, it is when me.
My phase plug is suspended from the outer frame and almost touches the cone. This allows me to go back the standard version. The magnet is vented so should aid air flow. The dust cap has three coats of 90% PVA 10 % water as does the Wizzer edge. The Wizzer has three 1/3 inch cubes of acoustic foam at 120 degrees between Wizzer and main cone. The rest is paper as designed. What all of these mods do is reduce the cup colouration to a level where it seems as neutral as many modern speakers. Only a very old and good pair of Spendor BC1's I repaired recently showed where they fail. Be careful of BC1's, most don't sound this way. Alas the bass is not like a baffle although upper bass is.
I tried a very simple experiment I thought interesting. Take a light blanket to hang from the speaker back. My experiance of this was totally negative. Box colouration and no extra bass ( less in a transient way ). I could hear what was so remarkable completely lost. This does not fit well with theory. As I have the speakers near a wall it should be that this is an equal problem. It isn't. The room is very irregular, maybe this is no bad thing. What I should try is some soft tubes in an irregular layout at the back. It might work.
No Nonsense Gloss Mini Roller Sleeves Foam Pile 4" x 5" 5 Pack | 4" Rollers & Sets | Screwfix.com
Superdrug Mint/Silv/Blue/Pink 8Elastic Hb16090 | Superdrug
This was last nights star of 1926. If you can't hear the near stereo effects work at it. Hope the links work. The system works well with youTube. We are both music lovers, we met at quizes where between us often get 100 % if music for our team. All I ask is an even handed machine to suit all the sources we use.
https://www.youtube.com/results?search_query=The+Laughing+Policeman+-+Charles+Jolly+/+Penrose+
This also.
https://www.youtube.com/watch?v=tAGnKpE4NCI
https://www.youtube.com/watch?v=p77JoONFX8U
https://www.youtube.com/watch?v=yi96gfl_Dog
BTW. My speakers are exceptionally fast. I think when resonance is made reasonable and box colouration removed even a 12 or 15 inch cone will sound fast. If you get a cone repair kit it has almost no mass compared with what a box will do ( be it acoustic supension or whatever ). I never have problems with rumble or LP warps and use very little bass filtering to the RIAA. PA type speakers can cope. I even use my cheap Nokia phone as a sound source, it has MP3 storage and FM. It is almost as good as my expensive CD player and various FM tuners. The Toshiba laptop is awful, however it is easy on the ear. Like 1970's mid fi . That is something I can't explain. The Panasonic PVR is fantastic except it and the TV require a floating supply so as not to have hum.
My phase plug is suspended from the outer frame and almost touches the cone. This allows me to go back the standard version. The magnet is vented so should aid air flow. The dust cap has three coats of 90% PVA 10 % water as does the Wizzer edge. The Wizzer has three 1/3 inch cubes of acoustic foam at 120 degrees between Wizzer and main cone. The rest is paper as designed. What all of these mods do is reduce the cup colouration to a level where it seems as neutral as many modern speakers. Only a very old and good pair of Spendor BC1's I repaired recently showed where they fail. Be careful of BC1's, most don't sound this way. Alas the bass is not like a baffle although upper bass is.
I tried a very simple experiment I thought interesting. Take a light blanket to hang from the speaker back. My experiance of this was totally negative. Box colouration and no extra bass ( less in a transient way ). I could hear what was so remarkable completely lost. This does not fit well with theory. As I have the speakers near a wall it should be that this is an equal problem. It isn't. The room is very irregular, maybe this is no bad thing. What I should try is some soft tubes in an irregular layout at the back. It might work.
No Nonsense Gloss Mini Roller Sleeves Foam Pile 4" x 5" 5 Pack | 4" Rollers & Sets | Screwfix.com
Superdrug Mint/Silv/Blue/Pink 8Elastic Hb16090 | Superdrug
This was last nights star of 1926. If you can't hear the near stereo effects work at it. Hope the links work. The system works well with youTube. We are both music lovers, we met at quizes where between us often get 100 % if music for our team. All I ask is an even handed machine to suit all the sources we use.
https://www.youtube.com/results?search_query=The+Laughing+Policeman+-+Charles+Jolly+/+Penrose+
This also.
https://www.youtube.com/watch?v=tAGnKpE4NCI
https://www.youtube.com/watch?v=p77JoONFX8U
https://www.youtube.com/watch?v=yi96gfl_Dog
BTW. My speakers are exceptionally fast. I think when resonance is made reasonable and box colouration removed even a 12 or 15 inch cone will sound fast. If you get a cone repair kit it has almost no mass compared with what a box will do ( be it acoustic supension or whatever ). I never have problems with rumble or LP warps and use very little bass filtering to the RIAA. PA type speakers can cope. I even use my cheap Nokia phone as a sound source, it has MP3 storage and FM. It is almost as good as my expensive CD player and various FM tuners. The Toshiba laptop is awful, however it is easy on the ear. Like 1970's mid fi . That is something I can't explain. The Panasonic PVR is fantastic except it and the TV require a floating supply so as not to have hum.
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Well explained. What I really like about adding lets say 22 R is what simple theory says is almost exacly what you get from this CR filter. Looking at the 12 Lta impedance graph we see almost a pure inductor above 1 kHz. All in all 22R and some series resistance won't make the amplifer work too hard when in paralell. I have never tried my speakers with a car stereo and 12 V battery ( + 1 uF ). I suspect it would be excelllent. The one factory fitted to my VW has a very nice punch to it.
http://www.eminence.com/pdf/Beta_12LTA.pdf
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