Need Subwoofer Home Amplifier Recommendation

R

researchcapt

Audiophyte
I just built an 8 cubic foot sealed enclosure and installed a 21 inch Dayton Audio PSS545HE-4 driver. It is rated at 2000 watts RMS at 4 ohms. https://www.parts-express.com/search?order=relevance:desc&keywords=PSS545HE-4

I was going to power it with a 2 channel Crown 2502 bridged to a single channel. The power rating for this amp at 4 ohms is 2400 watts RMS. https://www.crownaudio.com/en/products/xls-2502

The problem is, there are no Crown 2502's in stock. The MSRP for this amp is $689.00.

I would like to be able to get into sub 20Hz territory.

I have increased my budget to $1000 and perhaps a little more so as not to eliminate what might be a better amp.

My first question is, would the Crown be the best amp given these parameters? I did find one available used but prefer not to purchase used.

If not the Crown, which amp would you recommend?

Another question related to my subwoofer, I have an Onkyo TX NR838 AVR.

Ideally, I would like an amplifier that allows me to tune it so the frequency response curve is as flat as possible. I do not remember the term for that function.

Is the subwoofer tuned before the AVR or is the AVR tuned first, so the LFE is correct. Forgive me if I am not familiar with any proper terms or technology. So please try to correct me on this.

Thanks,
David
 
lovinthehd

lovinthehd

Audioholic Jedi
I bought a 2502 used a coupla years ago but from a classified ad in a forum from a reputable member that had only been used in his home rig....YMMV. Maybe something from QSC instead of Crown? If you really want to spend some coin maybe a PowerSoft or SpeakerPower amp? :) I wouldn't rely on the avr for equalization needed for a sealed sub. You can get a miniDSP 2x4 perhaps for that to insert between the avr and amp, it's got all sorts of features to help out with setting up a sub (and up to 3 more with the same unit).
 
Verdinut

Verdinut

Audioholic Ninja
I just built an 8 cubic foot sealed enclosure and installed a 21 inch Dayton Audio PSS545HE-4 driver. It is rated at 2000 watts RMS at 4 ohms. https://www.parts-express.com/search?order=relevance:desc&keywords=PSS545HE-4

I was going to power it with a 2 channel Crown 2502 bridged to a single channel. The power rating for this amp at 4 ohms is 2400 watts RMS. https://www.crownaudio.com/en/products/xls-2502

The problem is, there are no Crown 2502's in stock. The MSRP for this amp is $689.00.

I would like to be able to get into sub 20Hz territory.

I have increased my budget to $1000 and perhaps a little more so as not to eliminate what might be a better amp.

My first question is, would the Crown be the best amp given these parameters? I did find one available used but prefer not to purchase used.

If not the Crown, which amp would you recommend?

Another question related to my subwoofer, I have an Onkyo TX NR838 AVR.

Ideally, I would like an amplifier that allows me to tune it so the frequency response curve is as flat as possible. I do not remember the term for that function.

Is the subwoofer tuned before the AVR or is the AVR tuned first, so the LFE is correct. Forgive me if I am not familiar with any proper terms or technology. So please try to correct me on this.

Thanks,
David
To answer you frankly, your 21 inch subwoofer is a professional audio designed driver and will never efficiently reach frequencies near 20 Hz. It's Qts is way too low for such infrasonic frequencies. Moreover, it is simply not designed for a closed cabinet.

Parts-Express say that its response will go down to 18 Hz. Ah Yes, at 20dB down possibly. You will never be able to get a very low flat frequency response with such driver. You need a subwoofer with a Qts between 0.40 and 0.45 to be installed in a ported box to obtain an efficient infrasonic response.
 
R

researchcapt

Audiophyte
Thanks for getting back to me Ninja and Jedi.

It looks like I made a mistake with the driver. I need to research this better for the next time I build a home theatre subwoofer, by asking you guys first. In the mean time, what is the best thing to do to make the best of my situation?

From what I have read, sealed subwoofers sound "tighter" than non-sealed subs. From an audiophiles perspective, isn't sealed better than the "boomier" ported subwoofers? I understand that sealed is not as efficient as ported, so why not increase the power going to a sealed to compensate for the difference? I understand the downside would be cost. But is there another downside?

Not to change the subject though, I am still looking for an amplifier to drive it.

Thanks.
 
Verdinut

Verdinut

Audioholic Ninja
Thanks for getting back to me Ninja and Jedi.



From what I have read, sealed subwoofers sound "tighter" than non-sealed subs. From an audiophiles perspective, isn't sealed better than the "boomier" ported subwoofers? I understand that sealed is not as efficient as ported, so why not increase the power going to a sealed to compensate for the difference? I understand the downside would be cost. But is there another downside?
Thanks.
What you have read or heard about a sealed sub sounding tighter than a ported sub is inexact. A driver in a well designed ported box can be as tight as any sealed one.
Don't believe everything that is published on the web, in some of the audiophools magazines, or by some sealed sub manufacturers.

I have been building speakers for over 50 years. Each of the three front speakers in my HT system include a 15 inch subwoofer in a properly tuned 8 cf cabinet. Of course, the drivers have to be well designed such as the Dayton RSS390HF-4 products. These perform as well and even better than some available commercial subs, and at a cheaper cost as a DIY project.

I would recommend that you replace your 18" sub with a RSS390HF-4A. Just modify your front baffle to accept the new driver. The cabinet should be tuned at 16 Hz for a F3 at 20 Hz. Should you have the room for it, you could eventually build a second enclosure, and you would have the equivalent cone area of the 21" sub but a lot more LF output with less amplifier power needed than with any sealed design.

If you decide to get this Dayton RSS series sub, the Crown XLS 1502 would be a good amplifier to drive it.
 
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R

researchcapt

Audiophyte
Thanks Verdinut. I did not know that about sealed versus ported. For my next subwoofer build, I would like to get into the subsonic frequencies as much as what is practical. I have a woodshop full of woodworking machines and a lot of woodworking experience, so making my own custom cabinet again is what I would like to do, perhaps use the sub I just built for the higher subwoofer frequencies and a new cabinet and driver for the subsonic frequencies? Does it make any sense to do this? I have read that having more than one sub fills the room more evenly...it evens out partial phase amplification and phase cancellation better? I have a 700 cu-ft room to fill with sound although it will be just one end of it where people will be listening from.

I am going to go with your advice and get the Crown 2502.

Lovinthehd,
I am going to get a miniDSP 2x4 that you recommend and hopefully get a flatter frequency response curve from the sub I just built. Are there any models/brands/sources that you recommend?

I am also considering selling the 21 inch commercial grade driver I bought, building a second identical 8 cu-ft cabinet, and buying the lower frequency drivers with the proper Qts you guys recommend. This would not be happening soon though. I'm still very curious how the sub I just built sounds.

Thanks for your help guys.
David
 
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Verdinut

Verdinut

Audioholic Ninja
Thanks Verdinut. I did not know that about sealed versus ported. For my next subwoofer build, I would like to get into the subsonic frequencies as much as what is practical. I have a woodshop full of woodworking machines and a lot of woodworking experience, so making my own custom cabinet again is what I would like to do, perhaps use the sub I just built for the higher subwoofer frequencies and a new cabinet and driver for the subsonic frequencies? Does it make any sense to do this? I have read that having more than one sub fills the room more evenly...it evens out partial phase amplification and phase cancellation better? I have a 700 cu-ft room to fill with sound although it will be just one end of it where people will be listening from.

I am going to go with your advice and get the Crown 2502.

Lovinthehd,
I am going to get a miniDSP 2x4 that you recommend and hopefully get a flatter frequency response curve from the sub I just built. Are there any models/brands/sources that you recommend?

I am also considering selling the 21 inch commercial grade driver I bought, building a second identical 8 cu-ft cabinet, and buying the lower frequency drivers with the proper Qts you guys recommend. This would not be happening soon though. I'm still very curious how the sub I just built sounds.

Thanks for your help guys.
David
For the RSS series Subwoofer recommended above, I had suggested the XLS1502 with which one channel is powerful enough to drive it to its normal operating limit.

I guess you meant a 7000 cf room. As for the 8 cf cabinet, is that the net volume taking account of bracing inside it and the space taken by the driver? That would be a minimum volume. Ideally, the net volume should be 9 cf for a slightly more effective LF response.

With a ported cabinet, you shouldn't need a miniDSP. Also, a Crown XLS series power amp has an onboard DSP.
 
lovinthehd

lovinthehd

Audioholic Jedi
For the RSS series Subwoofer recommended above, I had suggested the XLS1502 with which one channel is powerful enough to drive it to its normal operating limit.

I guess you meant a 7000 cf room. As for the 8 cf cabinet, is that the net volume taking account of bracing inside it and the space taken by the driver? That would be a minimum volume. Ideally, the net volume should be 9 cf for a slightly more effective LF response.

With a ported cabinet, you shouldn't need a miniDSP. Also, a Crown XLS series power amp has an onboard DSP.
No, the Crown's dsp in the XLS range is generally only suited to its purpose, a crossover between channels for a true bi-amp setup. Altho if a ported sub were tuned high enough and needed a protective hpf, maybe (gen 1 XLS only provided for a 50hz hpf whereas gen 2 goes a bit lower to 30 hz). No delay functions either let alone eq. A miniDSP HD (2x4) would work with up to 4 subs.....

700 cuft would indeed be small :)
 
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R

researchcapt

Audiophyte
Sorry, I meant a 7500 square foot room. It makes sense that for home theatre purposes that the room should be measured in cubic feet. With a 10 foot ceiling, that would be 75,000 cubic feet. Maybe 30,000 cubic feet of that room are where the listeners are seated.

I am confused. What equipment is necessary for tuning a subwoofer so the frequency response curve is as flat as possible? Do I need something other than a miniDSP? Is there such a thing as a graphic equalizer for a subwoofer where I can see real time results to amplitude using a microphone and a computer? I would really appreciate links to websites for a subwoofer tuner, (probably not the right word) you recommend for audio equipment. Thanks.

I am also confused about the power of the amplifier that I need. The speaker draws up to 2000 watts RMS. The XLS 2502 when crossed over into one channel at 4 ohms produces up to 2400 watts RMS. A Crown 1502 produces 1550 watts. So I am confused as to why one would want less power than what the speaker can draw? I was thinking that you want a little bit of overkill with the amp above what the driver can handle so as not to damage the amp. I understand that with that philosophy that the coils might be overheated and destroyed if one is not careful.

Is there a section of Audioholics for people who are building subwoofers from scratch? I used the REW design and graphing software where I learned a number of things. There is a lot that I need to learn still. Mostly about driver selection and tuning. I think I got the cabinet making part down having made some very rigid walls from 3/4 inch Baltic birch and reinforced with 4 inch ribs so there is no vibration. I built using transverses and laterals, like how a modern ships hull is reinforced.

Thanks Again!
 
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Verdinut

Verdinut

Audioholic Ninja
Sorry, I meant a 7500 square foot room. It makes sense that for home theatre purposes that the room should be measured in cubic feet. With a 10 foot ceiling, that would be 75,000 cubic feet. Maybe 30,000 cubic feet of that room are where the listeners are seated.

I am confused. What equipment is necessary for tuning a subwoofer so the frequency response curve is as flat as possible? Do I need something other than a miniDSP? Is there such a thing as a graphic equalizer for a subwoofer where I can see real time results to amplitude using a microphone and a computer? I would really appreciate links to websites for a subwoofer tuner, (probably not the right word) you recommend for audio equipment. Thanks.

I am also confused about the power of the amplifier that I need. The speaker draws up to 2000 watts RMS. The XLS 2502 when crossed over into one channel at 4 ohms produces up to 2400 watts RMS. A Crown 1502 produces 1550 watts. So I am confused as to why one would want less power than what the speaker can draw? I was thinking that you want a little bit of overkill with the amp above what the driver can handle so as not to damage the amp. I understand that with that philosophy that the coils might be overheated and destroyed if one is not careful.

Is there a section of Audioholics for people who are building subwoofers from scratch? I used the REW design and graphing software where I learned a number of things. There is a lot that I need to learn still. Mostly about driver selection and tuning. I think I got the cabinet making part down having made some very rigid walls from 3/4 inch Baltic birch and reinforced with 4 inch ribs so there is no vibration. I built using transverses and laterals, like how a modern ships hull is reinforced.

Thanks Again!
It only takes a few watts to get output from any driver. For instance, if a subwoofer can handle a peak power of 1000 Watts, it definitely doesn't need that much power to produce a loud SPL. It will just stand so much power for less than a second, a sudden peak, beyond which it will most likely be damaged. The XLS 1502 has enough power to drive the Dayton RSS390HF-4 subwoofer. IMO, a more powerful amp will be useless and could destroy it.

The tuning is the frequency at which a ported box resonates. The port size and volume determines the frequency at which you want to tune it. This tuning controls the motion of the sub and its frequency response. It's frequency has to be fixed based on the Thiele-Small parameters of the driver.

The way you build a speaker enclosure is excellent. Baltic birch plywood is the best material to build subwoofer cabinets, as it resonates at frequencies above subwoofer operating frequencies.

I recommend the following book to help you understand the designing of loudspeaker enclosures:
 
Verdinut

Verdinut

Audioholic Ninja
Sorry, I meant a 7500 square foot room. It makes sense that for home theatre purposes that the room should be measured in cubic feet. With a 10 foot ceiling, that would be 75,000 cubic feet. Maybe 30,000 cubic feet of that room are where the listeners are seated.
Is there a section of Audioholics for people who are building subwoofers from scratch? I used the REW design and graphing software where I learned a number of things. There is a lot that I need to learn still. Mostly about driver selection and tuning. I think I got the cabinet making part down having made some very rigid walls from 3/4 inch Baltic birch and reinforced with 4 inch ribs so there is no vibration. I built using transverses and laterals, like how a modern ships hull is reinforced.
Thanks Again!
With a 75,000 cf room, you need a lot of subwoofer cone area. IMO, and since you have the room, you could build four 18 cf cabinets each containing two 15" subwoofers. An alternate solution would be to use two 9 cf cabinets attached to each other. I would start with two and add on at a later date. You will save a lot of money by building them.

Also, should you want to get more involved into the building of speaker enclosures, I strongly recommend the following software with which you would be able to calculate port sizes and volumes for your projects:

Here is another good book on speaker building:
 
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R

researchcapt

Audiophyte
Wow...good info. Thanks guys.

I did not know Baltic birch had a higher resonant frequency than MDF etc. That makes sense since it is more rigid. You learn something new every day. I also like working with it.

Kinda off topic, but are there guys who build custom speaker enclosures for people who do not have the, time, knowledge or tools to build their own?...not necessarily with the drivers installed. I was thinking it might be a fun part time job. I have a huge workshop. I am retired and love woodworking.

Yesterday I saw a YouTube video of a guy who put 4, 15 inch subs in each corner of his home theatre to even out the sound. It made sense to me except that none of the subs could go below 20Hz.

I am wondering, when you are looking for a sub driver that can go below human hearing, what specs are you looking for?
 
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Verdinut

Verdinut

Audioholic Ninja
Wow...good info. Thanks guys.

I did not know Baltic birch had a higher resonant frequency than MDF etc. That makes sense since it is more rigid. You learn something new every day. I also like working with it.

Kinda off topic, but are there guys who build custom speaker enclosures for people who do not have the, time, knowledge or tools to build their own?...not necessarily with the drivers installed. I was thinking it might be a fun part time job. I have a huge workshop. I am retired and love woodworking.

Yesterday I saw a YouTube video of a guy who put 4, 15 inch subs in each corner of his home theatre to even out the sound. It made sense to me except that none of the subs could go below 20Hz.

I am wondering, when you are looking for a sub driver that can go below human hearing, what specs are you looking for?
It's the Thiele-Small parameters of the driver which will indicate if it can produce effective infrasonic frequencies.
 
lovinthehd

lovinthehd

Audioholic Jedi
Wow...good info. Thanks guys.

I did not know Baltic birch had a higher resonant frequency than MDF etc. That makes sense since it is more rigid. You learn something new every day. I also like working with it.

Kinda off topic, but are there guys who build custom speaker enclosures for people who do not have the, time, knowledge or tools to build their own?...not necessarily with the drivers installed. I was thinking it might be a fun part time job. I have a huge workshop. I am retired and love woodworking.

Yesterday I saw a YouTube video of a guy who put 4, 15 inch subs in each corner of his home theatre to even out the sound. It made sense to me except that none of the subs could go below 20Hz.

I am wondering, when you are looking for a sub driver that can go below human hearing, what specs are you looking for?
I've built my diy subs with baltic birch for two main reasons....less toxic dust and lighter to move around.....and stronger but don't need that particularly. Right now it's bloody expensive.

These guys do flatpacks just like you're thinking about, not for all sub drivers but they have some you might be interested in. Even a member here, try his thread https://forums.audioholics.com/forums/threads/gsg-audio-design-aiy-diy-subwoofer-q-a-thread.123997/
 
R

researchcapt

Audiophyte
I looked at many of the flat packs before building my 8 cubic foot cabinet. Those were helpful for getting ideas, especially for reinforcing the cabinet walls and for machine bolting in and not using wood screws for attaching the driver. I was going to use truck bed liner at first for the paint, but ended up smoothing out the paint and going with a number of satin black rattle cans. If I may say, the finish came out looking professional. It took a lot of sanding with 220 grit between coats. I will use a professional grade paint sprayer for next time.

I am first going to try the DSP built into my Crown 2502. If I am not happy with that, I will try the miniDSP HD. I am reading that the HD version has tuning available for subsonic frequencies that the base version does not.

I am also considering modifying my cabinet from sealed to being ported and tuned to 18 Hz, depending of how the modified DSP and Audyssey frequency response curve turns out.
 
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lovinthehd

lovinthehd

Audioholic Jedi
I looked at many of the flat packs before building my 8 cubic foot cabinet. Those were helpful for getting ideas, especially for reinforcing the cabinet walls and for machine bolting in and not using wood screws for attaching the driver. I was going to use truck bed liner at first for the paint, but ended up smoothing out the paint and going with a number of satin black rattle cans. If I may say, the finish came out looking professional. It took a lot of sanding with 220 grit between coats. I will use a professional grade paint sprayer for next time.

I am first going to try the DSP built into my Crown 2502. If I am not happy with that, I will try the miniDSP HD. I am reading that the HD version has tuning available for subsonic frequencies that the base version does not.

I am also considering modifying my cabinet from sealed to being ported and tuned to 18 Hz, depending of how the modified DSP and Audyssey frequency response curve turns out.
What dsp in the Crown will help? The HD version has a few advantages over the older unbalanced and balanced 2x4s....don't remember lower frequency capability being one but wouldn't particularly surprise me.
 
R

researchcapt

Audiophyte
I downloaded the Operation Manual for the XLS 2502 and It says it has DSP but there is no mention of how to do the subwoofer calibration. So I am at a complete loss in how to do this. Does anyone know how to do this or have a link to a YouTube video? Thanks.

I tried looking it up, but what is a balanced and unbalanced DSP?

For my situation, would it be better to purchase the miniDSP or the miniDSP HD? Price does not matter much if it will get me a flatter frequency response curve. I have seen people using their cell phone as a microphone, but wouldn't a real calibrated microphone like a UMIK-2 be much better?

I'm a little chicken here and do not want to damage my amp. How do I wire my amp for bridged mode.? The instructions are not clear. I have 4 posts, a black and red on the left labeled 2 and the same thing on the right labeled1. The labeling indicates I connect the two red posts. Is that correct?

Also, I have a JL Audio W7 enclosed cabinet, 13.5 inch at 2 ohms, 1500 watts RMS. I am thinking of using this subwoofer as a second subwoofer, but obviously not bridging the amp. Verdinut said that a XLS 1502 would be enough power to drive the 21 inch sub. So would it be a good idea to drive both subs with the XLS 2502?
 
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lovinthehd

lovinthehd

Audioholic Jedi
The dsp in the Crown XLS 2502 is for a crossover (to use one channel of the amp for a bass bin, the other for the top, more for stage/pro applications unless you have the right speakers for it). That's why I said the XLS doesn't have the dsp you might need for a sub generally (such as delay, equalization or applying high pass or low pass filters).

The unbalanced miniDSP 2x4 was their first version, the balanced version (with different voltage/connector capability essentially) came next, the latest one is the miniDSP 2x4 HD (believe the balanced is no longer offered, the unbalanced version is now just the basic 2x4). The HD version is more capable (more delay particularly). The Umik-1 or Umik-2 are decent usb measurement mics, Dayton's UMM-6 is another option. If using a phone there's the Dayton iMM-6 but I'd use the others with a pc and REW software....

The instructions for the 2502 to run bridged is pretty clear and detailed in the manual and it's even labeled on the back. Don't know what to tell you there.

You could put one sub on each channel and not run it bridged.
 
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