Sr124-dvc possibly in a wrong enclosure.

[csnut18]

I have a sr124-dvc powered by a c500.1. The sub is in a 1.21 cu ft sealed enclosure. I bought that enclosure cause polk listed that size in the description on their main page. I look in the owners manual and it says that it calls for a .88 cu ft enclosure which is much smaller than what I have it in. I am a bit concerned now. What do you guys recommend I do and what size box sounds best with this sub. I am not sure I am getting the best performance out of the sub.

[Greg Peters]

I have a sr124-dvc powered by a c500.1. The sub is in a 1.21 cu ft sealed enclosure. I bought that enclosure cause polk listed that size in the description on their main page. I look in the owners manual and it says that it calls for a .88 cu ft enclosure which is much smaller than what I have it in. I am a bit concerned now. What do you guys recommend I do and what size box sounds best with this sub. I am not sure I am getting the best performance out of the sub.

I assume you've listened to the sub in that enclosure for sufficient time to allow the sub to break in?

The .88 cubic feet number listed in the manual is the recommended size, plus driver displacement, for a total of 1.02 cubic feet. If you read the manual, the white paper, and the review in Car Audio & Electronics magazine (where Polk Paul recommended a 1.25 cubic foot enclosure for maximum sound quality), you'll see a range of suggested enclosure sizes from the .88 you mention up to the 1.5 cubic feet CA&E staffers felt would maximize low end performance.

Translation- between 1.02 and 1.5 cubic feet (relatively speaking), you're good.

Enclosures on the larger end of the spectrum will have better low end extension (and will sacrifice a little bit of power handling), while enclosures on the smaller end of the spectrum will have more "punch" in their response (with better power handling) and a higher resonant frequency, though at a slight expense of low end extension. 1.21 represents a nice compromise, in that you'll retain some punch, handle power reasonably well, and have better bottom end than compared to the smallest recommended enclosure.

I have my SR124 DVC in a 1.20 cubic foot enclosure, and have been pretty happy with the performance for the most part. I find the sub plays low very well, and has decent impact, and that the airspace keeps the sub pretty well damped. If I were feeling really experimental, I could build a larger enclosure and also simulate the 1.02 cubic foot box (by adding material to displace .18 cubic feet inside my current 1.20 box) to test out the SR's performance in the differently sized enclosures. Because I'd modelled the different enclosures and their effect on the SR's performance with software (Bassbox Pro), and saw the differences between .88 and 1.5 were relatively minor, I went with 1.20 as a compromise. After listening to the setup for a while, I think I'd prefer a slightly smaller enclosure, and when I get some time I'll throw a few bricks in the box to displace some air and listen some more before making up my mind for good.

Out of curiosity, what don't you like about the SR124?

I suppose powering it closer to it's RMS rating might get you some additional output. Make sure your gains are properly set with the 500.1 in the time being. If you could critique what you don't like about the SR, suggestions could be made to get you closer to what you want.

[csnut18]

Well I have the bass control knob installed by the drivers seat so I adjust my gains on the fly. I have the level set to the best possible sound. My main complaint is that the sub sounds a little boomy rather than punchy. It's possible that I would of been better suited with the 10 inch version of the sr sub especially considering I am running this in a 06 acura rsx type s which is a small car. I am not saying the sub is not puchy, it is, I just think it is a little too boomy and I would rather it be more on the puchy side. I have it in a sealed 1.21 cu ft enclosure. The c500.1 is giving it 550 watts at two ohms which is what it said on the birthsheet.

[Greg Peters]

If that's the case (and you're good at math), calculate the dimensions for something that will displace .19 cubic feet, pull the sub, insert object of the desired dimensions, re-install and do a listening test to see if it has the effect you'd hoped for. If so, you could probably build bracing into your enclosure that would displace the required air and stiffen up your enclosure as an added benefit.

[csnut18]

I don't have the skill to do that unfortunately. I am not bad at math but this is a bit confusing. If they recommend the enclosure size I have than maybe I just need more power on tap. Do you think I should get rid of the c500.1?

[Greg Peters]

More questions- what is the rest of your audio system? Do you have EQ, and if so, is it set to a flat curve in the bass region? Do you have a loudness setting engaged? What are your crossover settings for the total system?

It's possible tuning might be able to help you out without resorting to anything drastic.

[csnut18]

I have a c400.4 biamping a polk momo mmc6500 set up front. I am utilizing the pre-eq button on the c400.4 which is what is recommended. On the c500.1, I have bass boost off with the regular low pass filter set at like 65hz or something. Its well under 80hz. I didnt want the subs location being given away by the sound. I really don't know what else to say. I have a jvc kd-avx33 which is a fantastic headunit. I previously had a alpine 9885 hooked up to this system as it is before and the jvc greatly improved the sound.

[csnut18]

I should add that I have no external crossovers or equalizers except what is built into the momo amps. The jvc has no loudness feature. The alpine 9885 I had before did have loudness.

[Greg Peters]

I have a c400.4 biamping a polk momo mmc6500 set up front. I am utilizing the pre-eq button on the c400.4 which is what is recommended. On the c500.1, I have bass boost off with the regular low pass filter set at like 65hz or something. Its well under 80hz. I didnt want the subs location being given away by the sound. I really don't know what else to say. I have a jvc kd-avx33 which is a fantastic headunit. I previously had a alpine 9885 hooked up to this system as it is before and the jvc greatly improved the sound.

Sounds like everything's a "keeper".

What type of vehicle? Which way is your sub enclosure facing? Seemingly silly questions, I know, but there are a few tricks to try first.

[csnut18]

It is a 2006 acura rsx type s. The sub is mounted in traditional fashion in the box with the basket hidden in there. It is not mounted inverted or anything. The sub is pointing towards the brakelights or the back of the trunk if you want to put it that way.

[Greg Peters]

So far so good (sorry I missed you mention the car earlier :o ).

I don't know what to tell you- try lower the sub's LPF and see if it eliminates the "boom". I don't know if the 500.1 has a subsonic filter or not, but you could try to engage that if it does. You could also experiment with the xover settings on the 400.4, because if you have some frequency overlap between front stage and sub, sometimes things can get a little overwhelming in the lower midbass region. You could also play with the enclosure- firing back to the taillights usually re-enforces bass response (a good thing), but in your case firing forwards or upwards may be better if you've got too much response at certain frequencies.

I have mine in an SUV, with the sub firing straight back...it's about as closely coupled with the cabin as you can get, and I couldn't say it's boomy.

[csnut18]

It doesn't sound like the boomines is coming from an overlap of frequencies between the speaks and sub. Maybe I am just crazy or something. I don't think it's really that boomy. I just like tight bass and I thought it was going to be a little tighter. I also don't have a subsonic filter on the amp. Do you think throwing 700 watts at the sub which would mean me getting rid of the c500.1 is worth it in my case?

[Greg Peters]

Do you think throwing 700 watts at the sub which would mean me getting rid of the c500.1 is worth it in my case?

Nope...if your sub is plenty loud and you're not clipping the amp's output, keep the 500.1- it's a nice amp.

[csnut18]

Yeah it is a nice amp but 550 watts might not be enough.

[eloplayspolo]

what kinda enclosure is it?

[Jack from Indo]

I had a resonance frequency of around 53hz that caused my sub to boom quite a bit when any notes close to that were played, until I EQ'd it out. But I have a big empty van, which makes such problems worse. Still, maybe this is part of your problem?

Also, it is true that subs get tighter in a smaller enclosures as a general rule. Mine certainly does. (JL W6v2). Just throw a brick or two in there like Greg says and see what happens, before ya go spend more money.

[black magic]

I have 2 sr124dvc's in a sealed enclosure with a little more than 1.02 cu ft for displacement. Each is powered by the c500.1 at 2 ohms just like yourself. To be honest, I love the SR subs. I think they deliver really clean bass. They get loud, but not too loud. But that's prolly because I'm under powering them and they're in a sealed enclosure.

[monologuist]

I just finished setting up an SR124DVC in the hatch of my Saab 9-3. I have 1 of them in a box that is about 1.4 cubes. It is powered by a single Alpine PDX-1.600 (birthsheet says 740W RMS). I have SR6500 components up front powered by a C400.4, biamped.

So far my impressions are as follows:
1. Setup is not as loud as I thought it would be. But this is not necessarily a bad thing. Seems like a good balance with the SR6500's. I don't think it would be enough if i didn't have a hatchback and had a trunk instead.
2. My Alpine amp seems like it is a good match for the sub. It has some power on reserve even when my system is cranked....I had considered the PDX-1.1000 but it would have been overkill. If the c500.1 is a true 500w rms, I would say it should be adequate to power my setup, although it would be about the minimum I would use. I think the SR124 is the limiting factor in terms of DB in my setup though...the PDX amp has plenty of headroom.
3. Extension is good...I actually thought it would hit lower, but maybe the sub is not fully broken in yet.
4. The response seems to be very linear and accurate. I have had to do very little in the way of EQ. I just have the frontstage and the sub both crossedover at 63HZ, 24db. Not much in the way of hyped frequencies
5. I've played around a bit with Time Correction and Phase switching on my Alpine CDA-9887 with the sub...this can yield some pretty varying results. I would recommend this sort of tweeking if your head unit permits. I have yet to settle on whether I prefer the sub in phase or 180 degrees out. With 180 degrees, it seems to go lower, but it brings the bass stage backwards a little. With normal phase, the bass sounds like it is up front, but extension does not go as low. I wish the receiver had degrees of phase shift between 0-180.

Bottom line is, in no way did I find it to be a muddy sub...but I could see that if it is underpowered and/or the phase or time alignment is off you could run into problems. But nothing that can't be fixed, head unit permitting. Like I said, my Alpine PDX amp seems to be ideal match for it at around 750w rms, but I have never used the c500.1, so I can't vouch for it one way or other.