Setting up Subwoofer

Join HiFiMART Telegram Channel for offers & deals

Phil K

New Member
Joined
Aug 12, 2020
Messages
3
Points
1
Location
India
Hi readers ,

I have a pair of open baffle main speakers - using 8 Ohms , Tang Band and a single 12" Eminence Subwoofer . The latter is on H-frame .
The sub is driven by a DSP/plate amp = Dayton SPA 250 DSP .

The sub's audio output is NOT INTEGRATING with the main satellites .

Could somebody guide me through to get it right ?
Else where can I seek an audio specialist to get the DSP Controls set up ?


Cheers and regards .
 

yogibear

Well-Known Member
Joined
Jul 31, 2014
Messages
1,782
Points
113
Location
Jaipur
Hi readers ,

I have a pair of open baffle main speakers - using 8 Ohms , Tang Band and a single 12" Eminence Subwoofer . The latter is on H-frame .
The sub is driven by a DSP/plate amp = Dayton SPA 250 DSP .

The sub's audio output is NOT INTEGRATING with the main satellites .

Could somebody guide me through to get it right ?
Else where can I seek an audio specialist to get the DSP Controls set up ?


Cheers and regards .

How is TB driven and baffle size ? What is your current crossover point for woofers ? It’s very hard to make an OB sound worse than boxed speakers and I did not say that !

8E7BA018-5BA4-4656-B88D-6F34E3D9EA27.jpeg
 

yogibear

Well-Known Member
Joined
Jul 31, 2014
Messages
1,782
Points
113
Location
Jaipur
I guess your OB are front of HT. Where do the satellites roll off and where does the TB roll off ? Both must match. Eminence in H frame must not be crossed above 150hz. Ideally 120hz.
 

Phil K

New Member
Joined
Aug 12, 2020
Messages
3
Points
1
Location
India
Hi Yogibear ,

Thanks for the efforted reply .

I am with you that its difficult to go wrong on OBs .

For other forum readers - I may suggest that a venture in an OB design is rather rewarding - both in costing and technical jargon while still delivering pleasing sonic qualities .
However , the bass does get compromised . I guess this is due to cancellation by virtue of diffraction .

Specific to yr questions : The TB on OBs are very impressive and has Neo magnets . The visual build quality is very good .
Since it has a whizzer cone , it is more than good for most people , to be content with transient response to give articulate accuracy . But this is true for most of the mid/high freq bandwidth .
As mentioned above the bass does suffer .

Hence I did incorporate a single sub using a plate DSP/amp ( taking advantage of the non-directional characteristics of low frequencies .
The religious X-O freq for a sub is normally around 80 Hz . Personally for certain notions , I prefer to XO at higher than 80 Hz . My main reason is to reduce Doppler effect distortion which many like to ignore and shy away by hiding behind the curtain .

My Dayton DSP has XO upper limit of 120 Hz .
I have experimented it at 90 , 100 , 110 , 120 Hz etc . But no luck ! The bass output is still distinctly noticeable as to where it originates . Ideally the bass source shud not be noticed at all and shud integrate with the satellites .

There is a small mistake on my part . I made the vertical HEIGHT of the H-frame at quarter wave for 180 Hz . I should have applied 120 Hz for this computation . Concurrently , I believe that , this upset in quarter wave length has very negligible or zero impact . Many just design a frame enough to fit the driver size .

The conventional Driver of choice for sub , is the 15" Eminence which has a better Qts to suit an OB .
I hv employed a 12" Eminence , which as per manufacturer , is also suitable for this application .
I opted for 12" driver , to reduce frame dimensions .


The baffle size of my satellites are W/18" n H/36" .
The upper periphery edges are asymmetrically beveled and the Full Range TB drivers are offset horizontally in the Fibonacci Ratio . This offset is for my finickiness , rather than any proven truth . The beveling is for taming some diffraction troughs - wishfully . !

I have also tried out some permutations of the phase setting . But nil joy .
FYI : since the XO slope is a digital manipulation , it shud not have any vectorial deflection ( unlike in a tank circuit ) . I have focused on using this phase setting to time align the sub against the satellites .


Besides these settings , the plate amp has many other controls and five nos of EQ which can be kept in memory and select as desired . It here that I get also foxed !


How can you help me dear ??

Regards .
 

Attachments

  • WhatsApp Image 2020-08-13 at 10.36.21 AM.jpeg
    WhatsApp Image 2020-08-13 at 10.36.21 AM.jpeg
    63.9 KB · Views: 13
Top