kopidilo Posted April 23, 2021 Share Posted April 23, 2021 (edited) Hi, I'm using dual identical subs and recently just did a time alignment of my subs again based on a new nearfield sub placement. But I'm a bit torn what delay to use for my nearfield sub as I managed to get 2 very good results with 2 different delays. BUT the impulse alignment was not so st forward to observe due to the unusual sine curve shape for the farfield sub. Purpose: to eliminate the wide band/ problematic dips before I run room EQ. OPTION 1: Nearfield sub with delay 9.1ms (The nearfield sub's 1st sine wave is parked in the "middle" of the farfield sub's 1st sine wave See the unusual shape of the farfield subs' FR which the 1st sine wave takes longer to complete a full cycle? You can see the farfield subs' response is excellent in the room, but it has a wide band dip at 80-120hz. Which the nearfield sub's new placement covers nicely. But there is some cancellation between 55-75hz, which is an important region that I am trying to avoid a further dip. OPTION 2: Nearfield sub with delay 5ms (first peak of both farfield and nearfield subs' sine waves aligned) The integration between 55-75hz is better for this option. COMPARISON OF THE 2 OPTIONS TOGETHER: Option A gives a better combination 28-55hz, which i don't really need that region to add up so much because I'll be deploying a rising house curve between 100hz-20hz Option B gives a better combination 55-90hz, which improves the wide band dip in my room that I am trying to minimize Which option do you feel is better in terms of subs time alignment? Edited April 23, 2021 by kopidilo Link to comment Share on other sites More sharing options...
wechnivag Posted April 23, 2021 Share Posted April 23, 2021 I would go with option 2 personally, it has the most even sum across the entire range. Option 1 has higher sum in the 30-40hz range but there is a significant dip in the 65hz range. But end of the day, go with your ears. Maybe option 1 sounds better for low bass authority, and you don't quite notice the midbass difference from the 65hz dip. Cheers! 1 Link to comment Share on other sites More sharing options...
rayleh Posted April 23, 2021 Share Posted April 23, 2021 I agree that you should just trust your ears. If you are not able to differentiate then just leave it with either option. 1 Link to comment Share on other sites More sharing options...
Boxerfan88 Posted April 23, 2021 Share Posted April 23, 2021 (edited) 2(B). Edited April 23, 2021 by Boxerfan88 1 Link to comment Share on other sites More sharing options...
kopidilo Posted April 23, 2021 Author Share Posted April 23, 2021 (edited) 1 hour ago, rayleh said: I agree that you should just trust your ears. If you are not able to differentiate then just leave it with either option. Thanks rayleh. I'll definitely compare and recompare if i have the luxury of time. The problem is nowadays, with young kids at home, cant afford so much time to do the HT detailed comparisons (different from last time where no children yet) , recalibrate and then compare again, and repeat and repeat calibration till i get the best. Have to make wise efficient use of time based on data/ info i have keke Edited April 23, 2021 by kopidilo Link to comment Share on other sites More sharing options...
kopidilo Posted April 23, 2021 Author Share Posted April 23, 2021 (edited) 8 hours ago, wechnivag said: I would go with option 2 personally, it has the most even sum across the entire range. Option 1 has higher sum in the 30-40hz range but there is a significant dip in the 65hz range. But end of the day, go with your ears. Maybe option 1 sounds better for low bass authority, and you don't quite notice the midbass difference from the 65hz dip. Cheers! 30 minutes ago, Boxerfan88 said: 2(B). Thanks bro wechnivag and boxerfan. Looks like option B has 2 votes so far. How about the rest? All opinions are welcome Edited April 23, 2021 by kopidilo Link to comment Share on other sites More sharing options...
Boxerfan88 Posted April 23, 2021 Share Posted April 23, 2021 (edited) If you’ve time, search youtube for amir (asr) latest tutorial on frequency response. quite insightful tutorial. very narrowband dips (nulls) may not be that audible to our ears due to the way our ears work (bucketing of frequency ranges & averaging by the ear) bottom line, trust your own ears, as pointed out by other bros, and also mentioned by amir in his tutorial. it is my personal opinion that there is no need to go chasing for ruler flat frequency response. Edited April 23, 2021 by Boxerfan88 1 Link to comment Share on other sites More sharing options...
rayleh Posted April 23, 2021 Share Posted April 23, 2021 If I have to choose, I will go for 2 as the FR is smoother. I used to spend a lot of time measuring and recalibrating but guess the toil get the better of me and also due to my busy work schedule. What you like is the most important as like Boxer said, flat FR doesn't mean it is what you like and narrow dip is not critical. I would prefer to measure, calibrate, tune and spend the rest of the time to enjoy your gear. What is the point of spending $ and time if you don't get to truly enjoy them? 1 Link to comment Share on other sites More sharing options...
kopidilo Posted April 24, 2021 Author Share Posted April 24, 2021 (edited) Thanks rayleh and boxer. Yup no worries, i fully understand what u mean. My same sentiments too on hearing and flat FR. I would like to recap (as indicated in my post) and maybe my post was not clear, 1) my aim was not for a flat FR. It was to minimise a potential serious dip (i would see it as a potential wide band dip between 58-75hz) before i do room eq and then the house curve lifting. This will also minimise boosting for those freq. 2) time alignment of the 2 subs is super critical. A FR option that looks better than another doesnt mean subs are much more time aligned compared to another option. So i hoped that i could get views on which time alignment from an impulse perspective is more aligned to the ff sub's sine response. Because the time apart bet the 2 options is not small. Well, of cos 1 way is to keep comparing, test and hear it for myself, but time is also not a luxury now. So i hoped i could hear it from an impulse perspective 1st for my learning. Thanks for the inputs and help. Cheers Edited April 24, 2021 by kopidilo Link to comment Share on other sites More sharing options...
rayleh Posted April 24, 2021 Share Posted April 24, 2021 https://bobmccarthy.com/phase-alignment-of-subs-why-i-dont-use-the-impulse-response/ 1 1 Link to comment Share on other sites More sharing options...
rayleh Posted April 24, 2021 Share Posted April 24, 2021 https://www.audiosciencereview.com/forum/index.php?threads/manually-time-aligning-subwoofer-s-to-mains-how-to.15269/ 1 Link to comment Share on other sites More sharing options...
kopidilo Posted April 25, 2021 Author Share Posted April 25, 2021 (edited) thanks bro Rayleh for the links. Edited April 25, 2021 by kopidilo Link to comment Share on other sites More sharing options...
kopidilo Posted April 25, 2021 Author Share Posted April 25, 2021 (edited) On 4/23/2021 at 11:34 PM, Boxerfan88 said: If you’ve time, search youtube for amir (asr) latest tutorial on frequency response. quite insightful tutorial. Thanks Boxerfan bro. U mentioned ASR has a tutorial on freq response earlier. Can trouble u to post the link here pls? Hope to read it to get further insight. Is it this one - https://www.audiosciencereview.com/forum/index.php?threads/understanding-audio-frequency-response-psychoacoustics-video.22705/ Cheers and thanks in adv Edited April 25, 2021 by kopidilo Link to comment Share on other sites More sharing options...
Boxerfan88 Posted April 25, 2021 Share Posted April 25, 2021 8 hours ago, kopidilo said: Thanks Boxerfan bro. U mentioned ASR has a tutorial on freq response earlier. Can trouble u to post the link here pls? Hope to read it to get further insight. Is it this one - https://www.audiosciencereview.com/forum/index.php?threads/understanding-audio-frequency-response-psychoacoustics-video.22705/ Cheers and thanks in adv Yes, that's the one. He has recently produced quite a few nice video tutorials that I found quite insightful. 1 Link to comment Share on other sites More sharing options...
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