How to tune the SR's

MacLeod

I suggest making them on axis if possible. The SR's do have great off axis response BUT they dont equalize that well. Ive always had a lot of problems getting voices, especially female voices to focus up properly. The problem lies in the 1200-3200 Hz range and its VERY hard to tune out. If you can get them both on axis to you then that should help out a lot.

keith89

MacLeod wrote: »

I suggest making them on axis if possible. The SR's do have great off axis response BUT they dont equalize that well. Ive always had a lot of problems getting voices, especially female voices to focus up properly. The problem lies in the 1200-3200 Hz range and its VERY hard to tune out. If you can get them both on axis to you then that should help out a lot.

I agree that certain frequency ranges are hard to focus when they are off axis as I currently have them set up. This will be my winter project as I am working on an amp rack for my zapco dc reference amps as well as well as some other performance related upgrades.

black magic

Sounds like you have a fun project lying ahead! What car is this going into?

Kinetic

MacLeod wrote: »

I suggest making them on axis if possible. The SR's do have great off axis response BUT they dont equalize that well. Ive always had a lot of problems getting voices, especially female voices to focus up properly. The problem lies in the 1200-3200 Hz range and its VERY hard to tune out. If you can get them both on axis to you then that should help out a lot.

but if the tuning is not an issue, do the sound better off axis?

i put them off axis, but i have the Alpine Imprint processor, so it does all the job, actually i love the sound of them, but if i put them on axis, could they be better?

also i have them bi-amped, and now i can send more power to the woofer, in compare to the tweeter, and it sound a lot better, than all at the same power, that was a nice trick i learn from you.

keith89

black magic wrote: »

Sounds like you have a fun project lying ahead! What car is this going into?

2003 cobra. I was having a return fuel system installed with a few other mods over the summer so I had to take everything out of my trunk.

black magic

Nice ride!

Post up some pics when you're all done

keith89

black magic wrote: »

Nice ride!

Post up some pics when you're all done

Thanks. Here are some pics to get you started. The sub and amp setup are temporary. I'm going to sell those Alpine PDX amps or put them in my Focus. I got a pair of Zapco DC reference amps to replace them. I'm planning to do a fiberglass enclosure for the SR124 subwoofer, or possibly downsize to a single 10" or pair of 8" soundsplinters. Haven't decided yet. The SR124 and box from fishercustoms weighs about 50lbs! Need to shed some weight. I of course take everything out when racing.

The SR6500's are in the doors behind that dark rectangle panel. I plan to cut out this rectangle and make fiberglass speaker pods to put them more on axis. The pod will be the same rectangular shape and painted silver to match the door trim and the SR logo on the speaker grill.

black magic

Looks good... especially under the hood . Those newer Alpine amps are TINY!

exalted512

Looks great, why didnt you go with a double din?
-Cody

keith89

exalted512 wrote: »

Looks great, why didnt you go with a double din?
-Cody

I was always planning on upgrading to Zapco DC reference amps, so I was planning to get their single din in dash programmer as well. I plan on redoing the interior next year, so I may upgrade to a double din unit. I got a great deal on the AVIC N3 when I was looking for an indash system. I like the resolution of Pioneer's new F series units, but want a larger screen. I'll wait to see what Pioneer comes out with next.

dirthog

Just curious, what size box do you have for the sub?

black magic

dirthog wrote: »

Just curious, what size box do you have for the sub?

If your goal is SQ, around 1.2 sq ft should be what you aim for.

dirthog

black magic wrote: »

If your goal is SQ, around 1.2 sq ft should be what you aim for.

That is my goal and I had mine in a 1.2sp ft box but didn't like it. Now it's in 1.4sq ft much better.

So, do you have it in a 1.2?

keith89

I have mine in 1.2 after driver displacement.

black magic

I believe they recommend from 1.2 to 1.5 sq ft depending on what you're looking for. the lower end of the spectrum will be boomy and the bigger you go, the more low end bass you'll have.

Mine is a bit under 1.2 sq ft but I'll be building a bigger box when I find some time.

MacLeod

Mine is 1.25 before driver placement and its perfect. Virtually ruler flat from 20-40 Hz.

tk421

i plotted this many times on bass box pro (cheap and ver good software)

the SR6500 woofer looks best in a VENTED 1.0 cu ft enclosure, using a 2" port and tuned to 45 Hz. it's relatively flat all the way down to 50Hz and at that point u can set your cross-over with a steep slope.

i have to be honest. I've not calculated or considered port noise from such a small port. there is a formula/method to do so but it slips my mind now. gotta go back to old training notes.

MacLeod

Big difference between looking best and sounding best. I can vouch for the fact that in a 1.27 ft3 sealed box in the trunk of an Accord, it will play flat from 20-40 Hz. My EQ is set to totally flat on my sub. I cant imagine it performing any better than that.

tk421

^oops.. in my last post i was refering to the SR6500's 6" mid-bass woofer.

Apparently the thread moved on to subs... my bad.

MacLeod

Well obviously I wasnt paying attention either. You plainly state "the SR6500 woofer".

Interesting tho - but a 1 ft3 box for a midrange? Not sure that would fit inside a door panel!

audiofiend

Could you possibly fix the midrange by adjusting the 63 and 125 fundamental frequencies?

Would parametric eq's help with these freqs or not?

MacLeod

The more I mess with this, the more I think its a simple phasing issue as its smearing only to the right side. When I play with time alignment I can get things to focus up pretty good but the center image is over the steering wheel instead of the middle of the dash. So Im coming to the conclusion that the fix for this could be in speaker placement by getting them both on axis to the listener.

tk421

^^ my earlier pods were focused with the far speaker being on-axis to the listener. the near speaker was on-axis to the other listener. this is a common approach. it leaves the near speaker 30degress off axis which reduces the intensity, hence putting the image oer the center of the dash. of course, it takes a lot of measuring and listening to get this.

the horrible problem (which is why i scrapped the pods) is that they really change the stock apprearence of the vehicle. i drive a 2-door and they were so intrusive that my foot kept hitting it on entering/exiting the vehicle. as it's a daily driver AND i have a strong personal prefernce to stay with a stock appearance, i decided to go with the stock (flat mounted on the doors) option. i used time alignment to compensate. the center is now center on the dash and at about eye level. it changes slightly with frequency. my tweets are on the a-pillars, crossfiring and out of phase with the 6" woofer. i'm still not happy.

next step is to revie class notes and re-read the articles in CA&E on these topics. thinking of dash mounted pods using the tweet and a 2" or 3" home mid-range.

SQ guys are rarely satisfied :-(

keith89

I'm experiencing the same thing in terms of getting the stage focused in the center of the car. I will be making door pods to focus towards the opposite side occupant to try to get things to even out a bit. I will tune the rest with my zapco DC reference amps.

tk421

^^ even when i used TA to centre the image, it is a bit too low... pointing to poor speaker angles.

the stage is also non-uniform across the dash (instrument panel to blame). AND the centre focus changes with freq. (i suspect that separating the tweet from the woofer may cause this)

MacLeod

That is where a 31 band EQ for each driver is needed. Since each speaker is a different distance from you and has different obstacles between you and it and are at different angles, their output isnt going to be uniform. For instance, 200-400 is much hotter on the left by as much as 6 db. But 160 is 6 db hotter on the right. And this goes on all the way up the spectrum.

Greg Peters

MacLeod wrote: »

The SR5250's will play well passed 5 KHz at 90 degrees off axis but I found 5 K to be the best crossover point for them with the mids low and the tweeters high in the car. Any higher than 5 and things thinned out a little too much. I also found using shallow slopes like 12 db worked well. I found a 12 db cutoff slope on both mid and tweet made them blend in very well and kept my stage nice and high.

When my PXA H701 goes in, I'll probably forgo the passives and bi-amp.

So when I take my SR5250s active you recommend 5khz with a 12db/octave slope?

tk421

MacLeod wrote: »

That is where a 31 band EQ for each driver is needed. Since each speaker is a different distance from you and has different obstacles between you and it and are at different angles, their output isnt going to be uniform. For instance, 200-400 is much hotter on the left by as much as 6 db. But 160 is 6 db hotter on the right. And this goes on all the way up the spectrum.

ohhh... right.... damn.. i should get the alpine thinga-majig that auto-EQs the system... but i hear they add a bit of hiss... (CA&E review)

Kinetic

tk421 wrote: »

ohhh... right.... damn.. i should get the alpine thinga-majig that auto-EQs the system... but i hear they add a bit of hiss... (CA&E review)

ive got it, but a part from that, its awesome

just follow the alpine tech recomendations, not the manual, to run it.

if you need help, tell me..

MacLeod

Greg Peters wrote: »

When my PXA H701 goes in, I'll probably forgo the passives and bi-amp.

So when I take my SR5250s active you recommend 5khz with a 12db/octave slope?

Im a firm believer in having as many octaves as possible coming from a single source and if you can get the mids to play up to 5 KHz, then that leaves only 2 octaves coming from the tweeters and 6-8 coming from the mids (depending how low you play them). So I recommend at least starting with that setting and then tweak from there according to your own personal taste. Even now with my ST6500's Ive got them up to 5 KHz. They dont play that high as easy as the 5250's so I had to do a little tweaking to get them to work. I also have the mids rolling off at 24 db but the tweets at 12 db like before.

I also had good results with both crossed over at 4 KHz. 12 db slopes worked ok but I liked 24 db slopes on both when set at 4 K. Just seemed to focus up better.