Alpine SWR-1223D DIY Sub Build For HT - AVS Forum
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DIY Speakers and Subs > Alpine SWR-1223D DIY Sub Build For HT
braveheart123's Avatar braveheart123 11:03 AM 11-29-2012
Hi trying to tinker with WinISD to model a sealed or ported enclosure for Alpine 1223D. This is my first time with WinISD so I am not too sure if I am doing it right. I will be powering it with either Crown XLS-2000 or XLS-1000.

My other gear is Denon 3313, Klipsch Reference MK II (82, 62, 52), Klipsch SUB-12 (Which I will replace with the DIY sub), and BFD. I am listing down the TS parameters for this sub;

Alpine SWR-1223D T/S Parameters

Fs = 28 hz
Vas = 43 L
Qts = 0.47
Qms = 0.50
Qes = 8.5
Re = 1.85 ohms + 1.85 ohms
Xmax = 20 mm
Peak-to-Peak Excursion = 72 mm
Sd = 480 cm sq
Pe = 600 watts
SPL = 85dB

Can anyone help me design a proper box for it may it be ported or sealed??

If this goes well, I will make another one also. SUb choices are pretty much limited as I am in Pakistan. I want scary bass smile.gif both for movies and music with the 70:30 ratio respectively

LTD02's Avatar LTD02 03:49 PM 11-29-2012
"This is my first time with WinISD so I am not too sure if I am doing it right."

what did you come up with in winisd?
braveheart123's Avatar braveheart123 08:37 PM 11-29-2012
The following images show both ported and sealed boxes. Pls have a look and check if I am doing it correctly. The Transfer Function Magnitude graph shows T/S parameters also. Take a look at the values of Z and Xmax. Z should be 4 ohms and Xmax 20 mm as I am using serial connection of voice coils, but WinISD claculates them at 6 ohms and 17 mm respectively.

LTD02's Avatar LTD02 08:45 PM 11-29-2012
i really don't see anything wrong with your models there. i've got 20mm for xmax on the swr, you've entered 17mm but you have 20mm in your op.

with a ported, you need a high pass filter around 20hz or so. most plate amps come with something like that built in, so the excursion won't blow up as in the model.
braveheart123's Avatar braveheart123 10:46 PM 11-29-2012
Can I get away with not using HPF at 20Hz if I tune the box low enuf; let's say around 15Hz?? I have a crown xls1000 and xls2000 is on the way. They have HPF built in but it is way too high.....the lowest frequency that can be set is 50Hz for the HPF, which is usless for a sub.
braveheart123's Avatar braveheart123 11:48 PM 11-30-2012
Can anyone pls guide me on this
LTD02's Avatar LTD02 05:53 AM 12-01-2012
that's tough to answer because it depends on where your electronics rolloff, how much power you will be putting into the system, and the content. the lower tuning also results in more driver excursion above the tuning point, so keep an eye on that too.
braveheart123's Avatar braveheart123 06:11 AM 12-01-2012
I think um not getting any definitive answer on this, so I think I should go with the sealed box. I modelled a 50L sealed box with a Qtc 0.657 with the voice coils connect in series (4ohms). For now I will run it of Crown XLS-1000 in bridged mode delivering 1100 watts at 4 ohms. How do u think this will perform? I've checked the Xmax (20mm) doesn't reach its limits till 15Hz at 600 watts of input power
Audiophile1178's Avatar Audiophile1178 09:30 AM 12-02-2012
LTD02, is giving you the right advise... Basically, he's saying that you need to play around with it in WinISD to find out how a lower tuning will change the model. The one flaw with your ported vs. sealed graphs are that your ported model doesn't have a HPF on it so you're looking at an incorrect model. Add a HPF and then compare the two to see what you want to do. I have an XLS2500 and just ordered a Balanced MiniDSP for the HPF option, as well as, other features. I'm building two 10" sub boxes for my theater and the ported model blew away the sealed model in all areas except the sealed has the advantage in frequencies below 15Hz. At 20Hz the ported design is at 110.8dB vs 99.5dB for the sealed model. Those numbers are only for one sub. I'm building two since I already have two and the crown is a two channel amp. With two you can add 6dB to each of those numbers which means that the ported design model will be ~116dB at 20Hz! eek.gif That's not bad in my book for two 10" subs! That was what I needed to see and couldn't justify building the sealed boxes. The only downsize to the ported boxes is that I had to make them 4.5^3 ft. vs 1.3^3 ft. for the sealed. So there's the cost of more wood and the additional complication of making the ports. There's also the additional cost of $175 for the MiniDSP plus wires and cables to connect to the MiniDSP. So what I'm getting at is that it'll cost more to build a ported vs a sealed design as there's no cone control below tuning but most likely you're going to want to eq the sealed box to tame the peaks and nulls so you'll end up getting the MiniDSP anyway. That leave the only real difference of having a bigger box, the cost of more wood and the additional complication of making the ports.

Basically, what I'm trying to say is that if you're only building one 12" sub box. I think that you're going to be pretty disappointed if you build the sealed design as it won't have the output that I'm sure you're looking for but it'll roughtly cost you an additional $200 american dollars (the cost of a MiniDSP) to build a ported design.

BTW, don't forget to add a HPF to your ported model so that way you're making a proper informed decision.
braveheart123's Avatar braveheart123 11:38 AM 12-02-2012
Thanx for your advice, but that's what I asked if I can get away with not using HPF on a ported model if if tuned the port low enuf i.e. arnd 15hz. Very few movies dig that low. The Xmax blows out of proportion below the tuning frequency. So if my content doesn't dig close to the tuning frequency (15Hz) and Xmax is within limits at the tuning frequency, would I still require HPF?? I will be using 600 watts of input power.

Also, I modelled a 3.5 cu ft ported box tuned to 18Hz with 600 watts of input power having a slot port with the dimensions (H x W x L = 1 in x 16 in x 34.5 in). Pls have a look at the graphs. The Xmax is within limits down to 16Hz. Also note, my room is on the smaller side i.e. 2500 cu ft.

Cone Excusion With 600 Watts

SPL With 600 Watts

SInce you are using Crown XLS2500, could you pls let me know how much RMS power XLS1000 puts out at 4 and 2 ohms both in stereo and bridged mode?? Crown ratings are specified at 1 Khz.

Another important question, how do I limit the amp (XLS1000) to pump out only 600 watts in bridged mode at 4 ohms???
Audiophile1178's Avatar Audiophile1178 12:46 PM 12-02-2012
Very few movies dig that low.
That may be true but what will happen to your sub when a movie hits an frequency that low or lower? It appears that it'll be fine but to me it seems like a bit of a gamble. If you don't mind possibly blowing out your sub then do it and take the chance. Just remember that you modeled your sub at 600w of input power. That continuous watts and not peak. Remember that your amp could put out more watts for a short burst. I'm still building my subs so the amount of help I am to you is minimal but regarding the crown amps I can't tell you exactly how many watts it'll put out but it's not going to be that much less that what they stated. There's a thread on here somewhere discussing exactly what you're asking me... How to calculated 1 Khz ratings into 20Hz-20Khz rating. I think it was ~15% less power than stated or something along those lines. Also, you said that you're signal going to the crown is from a denon avr. That denon avr is probably not going to put out enough volts out of the preamp. You have a consumer product being connected to a pro product. While it may work you're not going to get the full output from that amp either. I had the same problem with my XLS 2500 and my onkyo processor. It sounded good but I had to crank the levels way up to get any decent output. I then bought a samson s-convert and it literally sounded like the power double without any adjustments to the levels so you have to take that into consideration as well. If your XLS 1000 is putting out 550w at 2-Ohms then just going directly to the crown considering the loss of voltage you might only be putting out 300-400watts. I don't know for sure I'm just giving an example. There's tons of threads on here discussing pro amps being connected to avrs and the lack of voltage required to get that pro amp to work at full capacity. Again I'm fairly new to all this but regarding controlling amplifier power I always thought of it as being if your avr is at 50% volume then the amp should be at 50% power. I don't know if that's exactly correct but seems perfectly logical to me.

Again, I'm not as educated on these things as other people I'm just rying to give you whatever knowledge that I might have. smile.gif
Mrkazador's Avatar Mrkazador 01:53 PM 12-02-2012

Running a ported sub without a high pass is pretty risky for home theater I think. Unless you know that specific movie you are about to watch doesn't have any content below 20hz and be careful of the volume knob. There are a few movies that go down to 10hz but those are pretty rare, I can only think of Hulk right now. I use a Denon 2312 with a EP2500 and puts out more than enough volts. The gain knob on the amp is set to about 1/4 of the way. I measured the lfe output with a multimeter and I was able to get 4.8v with the sub output at +12. You can test this yourself, find a 60hz test tone and measure the lfe output with a multimeter.

braveheart123's Avatar braveheart123 09:01 PM 12-02-2012
I then bought a samson s-convert and it literally sounded like the power double without any adjustments to the levels so you have to take that into consideration as well.

I am using ART CleanBox Pro to match pro amp level smile.gif. Btw I had Onkyo 809 that put out a paltry 200 millivolts. So switched to denon 3313. Its pre voltage is better than onkyo but still underpowered for the xls1000. Anyway thanx loads for your help and prompt replies.
braveheart123's Avatar braveheart123 10:16 PM 12-02-2012
I measured the lfe output with a multimeter and I was able to get 4.8v with the sub output at +12

I think 4.8 Volts from sub pre-out with the sub level at +12on AVR doesn't mean anything and translates to not more than maximum 0.7 volts at 00 sub level on avr at normal listeing levels. I think your behringer is still under powered. I checked it with my multimeter, the sub pre out level with sub level at 00 on the avr (Denon 3313)at 75dB volume before using ART CleanBox Pro was only 1 volt. After inserting Art CleanBox Pro and keeping the gain knob at 12 o clock (mid position), I measured it at 6.7 Volts keeping every other setting the same.

Get a Samsung S-Convert or Art CleanBox Pro smile.gif
Mrkazador's Avatar Mrkazador 10:39 PM 12-02-2012

At volume 00 I get 1.4v with the subwoofer trim level at 0. The input sensitivity of the EP2500 is 1.23v. Not to derail your thread but that should be ok...right? The amp is turned a 1/4 of the way and my subwoofer trim is at -5 on the receiver.

LTD02's Avatar LTD02 11:10 PM 12-02-2012
"At volume 00 I get 1.4v with the subwoofer trim level at 0. The input sensitivity of the EP2500 is 1.23v. Not to derail your thread but that should be ok...right? The amp is turned a 1/4 of the way and my subwoofer trim is at -5 on the receiver."

yes. "input sensitivity" on pro amps means the amount of voltage necessary that must be provided by the receiver into the pro amp in order to hit the rated max output of the pro amp.

example: let's say an amplifier "amplifies" the input signal by 40 times and has a maximum output signal of 60 volts. you would need to put in 1.5 volts in order to get the full potential of the 60 volts output. if you only input 0.5 volts, then the amp can only boost it to 20 volts, which is below its capability.

"input sensitivity" is not a very intuitive concept for a person new to all of this, so it is a good question.
braveheart123's Avatar braveheart123 11:13 PM 12-02-2012
I am not too sure but the sub pre-outs on Denon 3313 and 2312 put out the same volts. 1.23 Volts input sensitivity for the EP2500 is still on the higher side for the consumer level AVR to match. OK this is what I did;

  1. Set the master volume on AVR at my reference listening level (75dB on SPL meter) with all the speaker trim levels at 00 on the AVR. The volume on master dial read -6dB on reference scale. For level setting, I used a wideband pink noise that covered the frequencies from 60hz to 90hz.
  2. Then I disconnected all the speakers and the DIY subwoofer.
  3. I added ART CLeanBox Pro in the sound chain by hooking sub out of the avr with rca cable and set the input level on it to the max.
  4. Set the master volume at -6dB on AVR and and output level on Crown XLS1000 all the down to its lowest position.
  5. Ran the same wide band pink noise that was used to set the speakers levels and slowly raise the level attenuators on XLS1000.
  6. I left the output gain knob where the clipping LEDs lit constantly. This was at 12 o clock position.
  7. Then without changing any other setting, I checked the output vlotage of the Art CleanBox Pro and it was 6.7Volts.
  8. Then I hooked up the DIY sub and ran internal test tone for the sub from the AVR. Before checking the sub level I set the master volume on the avr to -6dB keeping every other setting the same and measured the sub level on SPL meter. It read 80dB, so, then I set the sub trim level to -2.5 on the avr so that I get 78dB on the SPL meter.
Note: At this point, I do not chnage the gain setting on crown. Rather I increase or decrease the sub level on the avr depending on the material I play. I hope this helps.
Mrkazador's Avatar Mrkazador 02:32 PM 12-03-2012

I have a feeling I'm doing it all wrong lol. If I get 1.4 volts at 0db, my subwoofer trim should be at 0 or close to it, not -5. I found this guide with lots of information which I have to try out one day.

Audiophile1178's Avatar Audiophile1178 04:26 PM 12-03-2012
braveheart, those setup steps seem about right to me. At least, that's what I would do. I always find it funny when people say that they calibrate their system at -6dB and what not. I can't even get close to that without blowing out an ear drum. I use my onkyo 885 test level setting and all my speakers are putting out ~82-83dB at that level. Rather than bump all the levels down equally to reach 75dB I just calibrate the system to those levels. After all we really just want each speaker playing at the same level. I usually watch movies at -19dB on my onkyo and it's plenty loud. One time, I connected the crown xls 2500 to my mains I couldn't get any louder than -30dB on the onkyo with the crown gain halfway up. At those levels my radioshack meter was reading 100dB. Mind you I have a small living room and sit about 9 feet from my mains. It was still very loud and my ears were ringing pretty good after that. My downstairs neighbor was with me when I was doing that test and he was drooling at my modest system. biggrin.gif I'm sure that my system is nothing compared to what a lot of you guys have on here though.
braveheart123's Avatar braveheart123 10:45 PM 12-03-2012
I always find it funny when people say that they calibrate their system at -6dB and what not.

I don't go beyond -15 max on the master volume with the speaker trim levels 00 on the avr for at least the front three speakers. So, in reality I am listening at 66dB. For action movies, this is plenty loud keeping in mind you will get transients of 20dB in short bursts. So, during transients, that would be 86dB. And mind you LFE is a separate track in 5.1 input stream, which is already 10dB hotter than all the other channels. So, you wiill be hearing transients in LFE at 96dB.

There is a reason why I do not cut the trim levels down to -9, -8 dB. If you let Audyssey or any other auto eq program to set the system, it sets your system keeping the master volume at 00. That's the reason why we get channel trims to around -8, -9 dB at listening position. Normally ppl sit 10-12 feet from the screen and speakers. I do not do this coz it kills the dynamic range of the system.
If the speaker trims are 7-8 db below the reference, then keep in mind that the redirected bass is also 7-8 db below the reference. Whereas the LFE that is separately mixed is 10dB hotter. So the difference between redirected bass and LFE is close to 17dB.

The net result is that you get weaker redirected bass and you try and bump up the bass to get it stronger. So, although you get stronger redirected bass, but it sends the separate LFE channel off the chart resulting in boomy bass or the sub bottoming out when LFE is also played with the redirected bass (which is derived from the main channels so it has the same level as the signal in speakers).

Bear in mind when we bump up the sub level in avr uptill 00 trim level, we are not increasing the bass. We are just letting more redirected bass flow into subwoofer which is already present in the recording mix. Imagine it as a valve on a water pipe. The valve does not produce extra water. It can only let as much water flow out of it as it is there inside the pipe. So the key is to preserve the maximum signal by keeping the speaker trim levels close to 00 on avr and set the system at 75dB with master volume manually.

Just my opinion
Ricci's Avatar Ricci 11:58 AM 12-04-2012
There is a major mistake in logic that often occurs when using the receiver test noise to set gain structure especially when making assumptions that there is not enough voltage potential available for your pro amp to produce its maximum output.

The internal pink noise signal is -30dB from the potential output a main channel may be asked for and for the sub channel -40dB from the potential output. If considering redirected bass from 5 main channels as well this signal is -48dB lower than the potential maximum signal strength. A VERY weak signal compared to what you experience with actual movies or music and intentionally so. Pink noise at even 75dB is very annoying that is partly why the calibrations signals are very much reduced in level.

If a 75dB signal requires 1v from the output... A maximum level 123dB signal out of the SW jack at REF level will require >250 volts. This is equivalent to an increase of 63,100 x the power.

You should never use the internal pink noise signal for calibration to determine if your pre-pro/ receiver has enough voltage for your amp to reach full output. It is far too tepid of a signal. Even with the master gain maxed out and the channel trim maxed out it will still be about 20dB weaker than the potential that is there in movies. Your receiver output will be far from clipping at this output. Whatever signal is used should be strong. A 0dB sine wave tone input into the system instead is much better. You are testing for maximum voltage like when a bomb blows up in Batman and you have it cranked and whether your receiver is going to clip without the amp getting enough juice to produce full power. What you are not testing for are the tiny voltages that occur when the weather channel is on at -40dB on the master dial. Should your 2000w pro amp be slamming your subs and clipping when watching the weather channel at -40? Of course not so why would you expect to get this result with such a signal? If you are judging this stuff on the basis of the internal calibration noise in the receiver this is essentially what you are doing. You want to push the preamp output with a very hot signal to the point that it is clipping and see if that is enough to get the amp into clipping. Usually the amp will have run into clipping long prior to the receiver hitting clipping and the amp can be run with the trims turned way down indicating absolutely no reason to use a booster. I have never needed one with any pro amp or receiver I have used and there have been a LOT of different brands.

Of course signal boosters boost the signal. That is exactly what they are designed to do. That does not mean that they are needed in most cases. They also will boost any hum or line noise as well so if you do not need more clean voltage than the electronics ahead of it in the chain can provide you are only degrading the signal by introducing it.

I only mention this because i have seen a lot of guys make this mistake. Moral of the story is that you need to determine the maximum output potential of the preamp output. This is why this should always be done with all speakers disconnected. if you stop prior to either amplifier clipping or preamp output clipping you do not know if you have enough voltage or not.
zheka's Avatar zheka 01:47 PM 12-04-2012
Originally Posted by Ricci View Post

. Moral of the story is that you need to determine the maximum output potential of the preamp output. This is why this should always be done with all speakers disconnected. if you stop prior to either amplifier clipping or preamp output clipping you do not know if you have enough voltage or not.


What's a good way to identify the max clean sub signal output the AVR is capable of? How do I tell that the preamp is clipping?

thank you
Ricci's Avatar Ricci 08:19 PM 12-04-2012
Use a free audio measurement program like REW that has a signal generator and an RTA. Run the audio out of your pc into the receiver aux in. Set the signal generator for a sine wave. 60Hz is good for bass. The SW output should be run back into the pc or sound card and monitored with the RTA. Crank up the output until the distortion jumps dramatically this is the onset of clipping. You will see the sideband harmonics jump up. REW will even tell you the THD% real time. 1% is a good stop point. First start by ensuring that you aren't clipping the input to the pc or sc so set it at minimum gain. Before turning up the receiver levels turn up the output signal from the audio program and sc with the receiver output set low and make sure that you aren't overdriving the input into the receiver. If you see distortion jump up with the receiver turned well down that would be either input clipping or sc output clipping. Set the levels out from the sc just below that point then leave them alone. Then turn the receiver up on the master while monitoring the distortion in the RTA you may even have to boost the channel trim as well. You may have enough voltage to clip the sc input even with the sc input sensitivity set to minimum. If so just stop there as you won' t be certain what happens past that point. Once you get the receiver gain set to where it is just below clipping plug the output back into the amplifier instead and run the signal and monitor the clip light on the amp while adjusting the input trim on the amp. If the clip lights are lighting up you have more than enough gain and this confirms it. Find the spot on the amp trim where the clip lights just start to stay on solid. This ensures that your receiver will not clip until your amp is already clipping hard and allows the least amount of gain needed at the amp which can help combat hum and noise. Avoid messing with the amplifier trim after this. At this point you can unplug the amp again and take a cheap hacked up RCA cord and connect a dmm to it and measure the voltage if you are curious. You can also do this for the main channels which will max out at somewhat less voltage usually. You only need do one of those the rest should be similar.

All speakers should be disconnected or off during this. All EQ should be disabled dynamic, Audyssey, external, etc...

If you have other devices between the receiver and amp such as a minidsp or a Dcx. You move onto these after the receiver one at a time until you get to the amp. You should maintain the strongest clean signal you can up to the amplifier. The amplifier should clip first before anything else. Again avoid adjusting any input or output trims after this is done except for the receiver settings.

When EQ is enabled things get more complicated. If it is in the first unit in line the receiver you need not mess with anything. If it is after the receiver you may need to adjust the input and or output trims for the device doing the EQ. Boosting is not what you have to worry about so much it is cutting which will allow the input to clip on the device EQing prior to the output producing enough voltage to clip the amp. So if you have a deep cut it is then possible to clip the EQ devices input prior to getting full power from the amp. At this point after EQ in an outboard device you can run its output into the sc and Measure the EQd response shape of the outboard EQ device only! to determine how much cut is there and increase the EQ devices output by a corresponding amount. This last part is not necessary if you have more than enough headroom that you will be very unlikely to need it. It is only needed if you want to be able to get EVERY scrap of output the system is capable of at any frequency.
zheka's Avatar zheka 10:25 PM 12-04-2012
Thank you very much!
braveheart123's Avatar braveheart123 12:43 AM 12-05-2012
Ok guys now back to my problem coz I think the thread has deviated from its original purpose, but no worries people got some useful info out of it.

I built a roughly 50L sealed box to test my sub and took the FR in REW. Pls have a look at the WinISD modelled FR and compare with the actual room response. They do not match at all. I am surprised at the low extension. The roll off starts at 16hz. I tripple checked it in rew. But this is how it is.

Can someone tell me what wrong am I doing here?? I am skeptical coz Crown goes into clipping, which never happened before and listening experience is way below par. I mean looking at the room response, I feel elated but listening is just not good. Maybe crown doesn't have enough power to match the projected in-room response or God knows what.

The sub doesn't bottom out but sends crown into clipping even at 15dB below reference during 20dB transients. It just does not have any punch. Can someone help?

WinISD Modelled Response

In-Room REW Response

I am not using more than 4dB of gain on 2-3 filters in BFD, rest all are cuts. Do you think Crown XLS1000 is running out of steam??

I am planning on getting Behringer iNuke3000 DSP Amp coz it has a floating point HPF and the lowest setting is 20Hz. I can use this amp for my ported builds. Is this amp any good?? I've heared the fans on these models are noisy. Which fan do i buy to replace?
LTD02's Avatar LTD02 01:14 AM 12-05-2012
"They do not match at all."

winisd is a 2pi space if you were measuring a sub in an open field.

rooms have modes, boundary gain, and pressure vessel gain depending on the dimensions and the construction of the room.

the thiele small parameters that underlie winisd are not meant to predict room effects, just roughly the effect of a driver in an enclosure.
braveheart123's Avatar braveheart123 03:04 AM 12-05-2012
Then it means that I have a tremendous response, at least on paper eek.gif But the listening experience is far from as good. The sub ouput just sounds anaemic and strangulated, but it does not bottom out.

Why does crown go into clipping at even 15dB below reference? Does it mean the amp runs out of juice?? How about Behringer iNuke 3000 DSP??

Pls guide me on this.
LTD02's Avatar LTD02 03:30 AM 12-05-2012
my guess is that your audyssey thing is the problem.
Ricci's Avatar Ricci 08:18 AM 12-05-2012
Can you show the raw response with no EQ and no smoothing together with the after EQ response? If I had to guess there is a lot of boost being supplied somewhere and it is requiring a lot of power from the amp.
braveheart123's Avatar braveheart123 09:44 AM 12-05-2012
I checked the raw response without audyssey and dynamic eq. It is roughly the same. Instead of running the sweep through REW, I ran 0dBFS (20Hz, 30Hz, and 60Hz) sine waves at my reference volume. On all three frequencies, the Crown went in hard clipping. It means it just doesn't have enough power to drive a sealed sub.

I am running Crown in bridged mode (1100 watts at 4ohms "1KHz"); but still it is unable to hold even at 60hz. That explains why i get no punch. What do u guys think???

Also, I have ordered Behringer iNuke 6000 DSP model. Any thoughts on this amp??
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