Mixed thoughts on BP1503 (1 Viewer)

[Shawn Solar]

Hmmm, It seems I've come to a final opinion on my new BP1503 sonosub. It is a 160l, tuned to 20hz by a 6" dual end flared port, 28" long. I used the threaded-rod-Through-the-tube aproach using 3/8 threaded rod and T-nuts on the other side. It is tightened together at the bottom base plate. With plastic feet 4" high covering the threaded rod and spacing the woofer from the bottom plate.

I Eq'd it using my BFD and sinewaves(the 70hz inductance hump was met with a nice suckout that complimented the hump). I applied the house curve to it. I basically just set the eq using the raw spl data from my metre. I tried it behind the couch, in front corner and in the left corner. I only used the one side of my amp(figure 400watts @4ohms) Due to a malfunction in the other channel. My room is about 3000cuft. The front wall is 10ft across jogs in 2ft then across another 9ft.

My old sub was an Energy microstar 12.1 servo sub. Think Velodyne hgs 12 without the 25hz and under bass. It was a quality sub just did not go low or loud enough. But was perfect for music. I was a little worried about going from a sealed to a ported sub but I wanted lots'O'bass down low so I went for it.

My expectations for the sub were high and I was not disapointed. On most rap it was unbelievable. just a clean as the energy, louder and quite a bit lower than I'm used to(with only 400watts). It seem to have bass that was a lot more tactile in it's approach moving the couch and vibrating the pictures a lot more then the sealed energy. I then tried it with Lord of the Rings. It was down right scary. DVDs fell off the shelf doors and the wall unit were just shaking. But It was too good to be true.

The next day I decided to try some different music. I listen to a wide variety of music, rap, country, alternative and heavy metal are all on the shelf. So I put in some system of a down. I was mainly listening for attack and decay. It can be said that there is quite a differnce in sound between sealed and ported cause the ported 1503 just did not have it. When the kickdrum hit it blended in with the rest of the music. It just was not as hard hitting. Oh it was tactile enough just something was missing. Kind of like hiiting your knuckle against hardwood floors versus linoleum. hardwood floors jsut sound harder. The more I listen to music the more I found this true. Metallica, ACDC all had the same lack of "slam".

This was not a huge diffrence but noticable. The main problem right now is I can not seem to get it to blend with my mains as I soon found myself adujsting and re-adjusting the phase and level. It didn't sound like the bass was too low or too loud but almost like there was a hole in the upper bass frequencies between 65-85hz. But my readings with my spl metre contadict this. Actually response after eq was actually quite good.+-5db from 20hz and up.

So I'm undecided on what to do. Could it be a phase issue? from that inductance hump. How would a sealed BP1503 sound? if I can not fix the problem I may just sell this driver and get a Tumult.

 

[Anthony_Gomez]

there are a few things at play here. first, the transient responce of a sealed will be better than a ported. 2nd, the rolloff of the 1503 in 160 has a saddle that sealed drivers will not have. 3rd, i would bet $$ that the velodyne and the microstar have a decent sise boost in the 25-40hz range. the reason you may not be feeling the punch is that the other subs are artificially boosted to force a punch.

Shawn, if you can wait a little bit, I will have a nifty program out. It is for the BFD. what I would want you to do with it is to EQ the 1503 for a flat responce (flatten the inductance hump and bring up the saddle). then listen to this withought any room EQ. if you are still missing punch, then there is an additional filter that I would add that would give you what the other subs boost with. I should have the program up and running in a couple of days with Paul V's help. after he gets the import feature running, you would be good to go.


NOTE: many people have found that after they EQ a sub flat that the sub is no longer "exciting". ..but in reallity, it is much more accurate. Those individuals, in time, end up liking the "real" responce over artificially inflated responces.

post away if you have any more questions.

 

[Shawn Solar]

Anthony,
I thought that might be the case. Though none of my measurements show this. I did apply a house curve to both subs by not correcting the spl metre and eqing for a flat response. The metre is weighted to reflect the deficiances of our hearing at low hz. So technically if I eq'd for a flat response at 20hz I was actually giving a 6db boost.
It wasn't so much the kick or slam so much as I could not get it to blend fully with my main speakers no matter the phase. The bass at the higher frequencies just seem to be out of phase with the mains but the lower bass was just right. I was getting this really off sound at certain frequencies. Almost distorted. I almost thought the sub was defective. Or the amp was not working properly. I switched the amp out and it did the same thing. I took out the woofer to check if something was vibrating inside.Could the sonotube be doing something. I have no leaks.
Unfortunately the sonotube had a little accident while doing so. It rolled off the deck and down the stairs:frowning: It is okay for the most part but has a sizable dent in the mdf and not repairable. So I am debating on to do a sealed box now.The sub was already out of the tube, Thank God Can't wait for your program
What I did for the setting the octave is
take the centre frequency and multiplied by the spacing I needed. so if i want to flaten from 60-70hz with centre frequency 63hz I would: take the 70 minus 63 for my range. so I need a range of 7hz. I then went 63*(1/8) to get 7.85. I then compare that to my range to see how close I got. So 1/8 octave spacing. grab that in decimal .125 and compare it until you find a match on the bfd. which would be 8/60 octave or .133. It was crude but a good starting point.
Oh what did you mean by the 1503 will have a saddle the sealed will not. Thanks.

 

[Anthony_Gomez]

The radioshack SPL meter is not that accurate down low. for example, I believe it is down about 6db at 20hz and 20db by 10hz (on average)
Idealy, you would want to EQ flat in room with the corrections.
On the weighting, use C not A. the blending was because on the otherside of the inductance hump, the 1503 dorta divebombs (look at the UNIBOX simulations with inductances around 12-14mh). you need to reduce the hump and add some gain on the otherside. the rapid change in responce effects the phase. let me play with my program and i will just tell you some rough numbers to use right now (does NOT account for the room and non-linearities! ...but will use the unibox responce). I will make a post soon after I download unibox 4.1 onto this computer. (assuming the comp does not crash ...mmx200)
how tall is the sonotube. if it is too tall, you could have some pipe resonances. is the tube lined or heavily stuffed?
For the MDF damage, just use a bit of bondo and sand it back out.
as for the saddle. model the ported responce. it doesn't have a smooth roll off like a tempest. it angles down, levels off, then back up and then back down (I'll double check that though. .....at the very least, it angles down ..then levels off then down again.
I'll be back

 

[Anthony_Gomez]

!!ANYONE
Please help me =)
UNIBOX 4.01 crashes on this computer.
..so I need someone to get me the frd file
Input the data for the 1503, use an inductance of 14 mh (I think that is about right for the inductance peak. use Shawns data of 160L with walls lines and no leakage with a tuning of 20hz.
update and export the FRD. do not include port resonances. you CANNOT use the pre 4.0 versions of unibox to get this data
then email me the file to the following address
[email protected]
NOT my hotmail account.
Thanks for anyone that can do this for me.

 

[Shawn Solar]

Anthony
I thank you for your time and effort. I have unibox but not the right version. I used 'c' wieghting but when I eq with correction values I find the response to be, well, flat. That is why I eq'd for the house curve. It is a mild boost applied to the lower frequencies to account for our hearing losses. When your up 6db at 20hz it does not sound boosted but flat as compared to the rest of the frequencies. the spl metre is wieghted to reflect ouer hearing And that is why we add corection values when we want a flat eq.

 

[Pete Mazz]

How did you calibrate the sub to the rest of the system? If you used the test tones from your processor, you may be calibrated too low in the xover region because of increasing energy down low with a house curve. If so, try a slow sweep around your xover region to blend the sub in.

Pete

 

[Anthony_Gomez]

Shawn, try these numbers. These assume the driver responce respond linearly. THis is ONLY driver correction. give it a shopt as is
freq:63
fine:4
gain:-6
BW:50
freq:100
fine:10
gain:3
BW:27
freq:25
fine:8
gain:3
BW:52
Let me know how this works out for you!

 

[ThomasW]

Oh what did you mean by the 1503 will have a saddle the sealed will not. Thanks.

Here's a LspCAD model so you can see a 'saddle'. It's formed by using low port tuning. A dip between the driver rolling off and the port output starting. Sealed boxes don't have this since there's no port or PR box tuning to augment the bottom end roll off of the driver

 

[Shawn Solar]

Thanks Anthony, Thomas

I will plunk the data in as soon as I put the tube together again. I have the endcap off so I can sand, fill and repaint. I have that textured granite paint. I see that saddle now. It is not as obvious in unibox but when you know what to look at I can make it out. Here is some raw data from different locations in the room. Its not the level but the difference between the frequencies I was interested.
Behind couch left corner: Front left corner:
20hz-64db/ 56hz-77db / 20hz-65db / 56hz-76db
25hz-67db/ 63hz-80db / 25hz-65db/ 63hz-86db
28hz-73db / 70hz-75db / 28hz-72db/ 70hz-81db
31.5hz-77db/ 80hz-68db / 31.5hz-82db/ 80hz-64db
36hz-76db / 89hz-70db / 36hz-83db/ 89hz-64db
40hz-82db / 100hz-62db/ 40hz-86db/ 100hz-73db
45hz-84db/ 45hz-82db/
50hz-82db/ 50hz-75db/

Right side,inside front corner 3ft behind mains:
20hz-77db 56hz-77db
25hz-81db 63hz-80db
28hz-84db 70hz-70db
31.5hz-87db 80hz-85db
36hz-82db 89hz-76db
40hz-82db 100hz-87db
45hz-60db
50hz-70db
It looks like I like the right front corner the best. But it is the furthest away and needs the most gain. behind the couch needed the least. and I don't like the big dip from the front left corner. what do you think. These are not corrected or level matched against eachother.

 

[Shawn Solar]

Well I got the sub back together. I replaced the tube with a slightly thicker 18"tube(and added a inch) and added carpet foam(not the rubber pad) to the inside and outside of the tube. I repainted the caps and changed the port tube to the plastic PVC.(Ihave 5ft left over to anyone that wants it) I changed all washers to the ones with the metal tops and rubber bottoms. I call it the Solarsub
I plugged in Anthony's numbers for the Bfd and re-used my old settings(for now). I am not sure what exactly made the difference in the constuction process my guess its the plastic port and the foam. It sounds way better. I can now say I'm happy with this sub. It is as clean as my old sealed Energy and goes lower and louder. Thanks for your help. Enclosure costs as follows.
18"sono-4ft long $25
10ft 6" pvc pipe $20
sock material $13
8'x6' foam pad $7
3, 3/8threaded rod 6ft $10-$15
screw, t-nuts and bolts and washers and spray adhesive $25-$30
mdf free
6" flared ports $50
total cost $110 plus finish
($6bucks a can for stone in a can and I used 2 cans plus one clear coat)

 

[Anthony_Gomez]

Glad to hear it all worked out for you! The enclosure damage was the subwoofer god's way of saying you need to fix something

 

[Shawn Solar]

Yeah them subwoofer gods are brutal. They also took out one side of my amp Oh well, I guess I have to use only 400watts for now. Might pick up a used audiopro 3000 for $700. I think it is 1250watts a side dynamic and 750rms. bridged is 2500watts and 4500 dynamic. I live with this for a while. Actually I might sell this driver to a friend and buy that tumult. I hope it is a drop in fit!