Hallo,
I need your comments on following changes on kit project from Troels Gravesen SBA-10.
http://www.troelsgravesen.dk/SBAcoustics-10.htm
This is original design (red is my change):
This is how I want it to be:
PLEASE COMMENT if you see any issue (fase alignment, time alignment, Diffraction…)
I have contacted Mr. Gravesen regarding this change but he cannot recommend it, because, it could affect sound in bad way.
Thank you
Milorad
I need your comments on following changes on kit project from Troels Gravesen SBA-10.
http://www.troelsgravesen.dk/SBAcoustics-10.htm
This is original design (red is my change):
This is how I want it to be:
- Originaly pyramid enclosure have 14° front panel tilt (just like in Jeff Bagby KAIROS project). I want to tilt complete front panel and back to approx. 10° (for me, 14° is optically too much) Gravesen mentioned in his project: ‘’ front panel tilt. 14 degrees seems an awful lot and more than needed for making an acoustically alignment of the midrange and tweeter. ‘’
- I will keep front panel dimensions and speaker placement
- I will keep enclosure volumes as in project
- I will change everything behind front panel due to Gravensen comment: ‘’ What’s behind the drivers is up to you, as long as you stick to volumes and port tuning‘’
PLEASE COMMENT if you see any issue (fase alignment, time alignment, Diffraction…)
I have contacted Mr. Gravesen regarding this change but he cannot recommend it, because, it could affect sound in bad way.
Thank you
Milorad
Crossover is roughly 460Hz, distance looks a little under 10cm, that's around 45 degrees. It will probably be OK and if you want to make adjustments they will not be large.
You may want to heed Troel's advice (LINK):
"If you change front panel dimensions, actual drivers, placement of drivers and cabinet tilt in the constructions shown on these pages, you need a new crossover, and I can't help. The crossover will no longer work as intended, so please do not ask because I would need your speakers in my workshop to adjust the crossover."
"If you change front panel dimensions, actual drivers, placement of drivers and cabinet tilt in the constructions shown on these pages, you need a new crossover, and I can't help. The crossover will no longer work as intended, so please do not ask because I would need your speakers in my workshop to adjust the crossover."
Yes I know this,
but I am DIY Enthusiast and I am on DIY Forum.
Speaker Designers usually doesn't care if you want to change something, even slightly.
Note that changing to a single tilted angle other than 14 degrees changes the vertical alignment of all the drivers not just between the woofer and the mid. The way you have drawn your proposal in red above appears to be misleading because you've put the single tilt at 14 degrees instead of your desired 10 degrees. So in the drawing, the relationship between the tweeter and the mid appears to stay the same but that won't be the case if you go with a single 10 degree tilt.
Now if you can manage to change to a single tilt angle while keeping the vertical alignments between all 3 drivers as close to the original as possible (maybe ~12 degrees?? maybe ~13??), then that would probably be ok, but I doubt that it's actually possible. I have heard the same as you though, that the phase relationship between the tweeter and mid can be more important than between the mid and the woofer but I'll let others more knowledgeable than myself weigh in on that score. Do note however, that it is not just the physical alignment between the drivers that matters, it is the combination of the physical alignment and the change in phase due to the xo that determines the final phase relationship and therefore also how the 2 drivers sum together at each xo point, both on-axis and off.
On the other hand, if you care more about the aesthetics than the absolute sound quality --> have at her.
Now if you can manage to change to a single tilt angle while keeping the vertical alignments between all 3 drivers as close to the original as possible (maybe ~12 degrees?? maybe ~13??), then that would probably be ok, but I doubt that it's actually possible. I have heard the same as you though, that the phase relationship between the tweeter and mid can be more important than between the mid and the woofer but I'll let others more knowledgeable than myself weigh in on that score. Do note however, that it is not just the physical alignment between the drivers that matters, it is the combination of the physical alignment and the change in phase due to the xo that determines the final phase relationship and therefore also how the 2 drivers sum together at each xo point, both on-axis and off.
On the other hand, if you care more about the aesthetics than the absolute sound quality --> have at her.
Not very helpfull I know but the change you are proposing is so subtle, looks wise, I'd be tempted to stick to the original design. There are still things you can do appearance wise to put your own mark on them. I appreciate its personal choice.. These were my first build and with zero woodwork experience and it was a challenge to say the least.
Are you planning to build the cabinets yourself?
Are you planning to build the cabinets yourself?
I think that you already have the answer from TG himself.
"I have contacted Mr. Gravesen regarding this change but he cannot recommend it, because, it could affect sound in bad way."
You just don't like the answer, so go ahead and do what you want.
"I have contacted Mr. Gravesen regarding this change but he cannot recommend it, because, it could affect sound in bad way."
You just don't like the answer, so go ahead and do what you want.
I care first about sound, then aesthetics.
I want to build Troels Design because I believe they are superb in sound, but aesthetic: I just don't like it, as much as I push myself.
Just look at those Kharma Designs:
Attachments
You might want to also look at these two designs from SB Acoustics that have the tilt back aesthetics you like and use, of course, SBA drivers.
https://sbacoustics.com/product/sasandu/
https://sbacoustics.com/product/rinjani/
https://sbacoustics.com/product/sasandu/
https://sbacoustics.com/product/rinjani/
Thank you. I have.
But bass drivers: 6" in Rinjani and 7.5" in Sasandu are just not on the level as one 10".
The two SB 7.5" woofers in the Sasandu have a combined cone area of 316 sq. in., which is actually a little more than the single 10" woofer in the TG SBA-10. They should produce plenty of bass for you.
Yes, I thought that too, but than I saw Troels statment:
"A 12" driver usually has a cone area of a little more than 500 cm^2. This is more than 3 times a ScanSpeak 18W/8531G00 driver! Imagine 3 x 6½ drivers in the same cab. A 12" based system can do things none of today's 6" skinny runts can do. It seems like most diy'ers start with a 6" 2-way making deep bass from 24-33 litre and an efficiency rarely exceeding 85 dB. We're all impressed from the bass it can make - but after some time we find out it really can't play very loud and we try another 6" driver or we make a 2½-way from 2 x 6" drivers. And we're never really getting anywhere. So, if you can handle a 60-70 litre cab, find a 12" driver, mount it on the side if the speaker must be skinny and use a 6" for midrange with a point of crossover around 250-350 Hz - and now hear what happens."
I don't see where Troel's statement has anything to do with the fact that two SBA 7.5" woofers can perform just as well as a single 10". Maybe even better.
Imagine 3 x 6½ drivers in the same cab. A 12" based system can do things none of today's 6" skinny runts can do.
Fs for the MW19P-8 is 29.5 Hz.
Fs for the 29RNX75-6 is 21 Hz.
I doubt that you would hear much difference with real music.
Fs for the 29RNX75-6 is 21 Hz.
I doubt that you would hear much difference with real music.