I want to incorporate a sub in an old 2-channel music system, please advise.

P

Paul DS

Audioholic
I have found myself listening to LPs and CDs recently after a long period of ignoring my music collections (most of which were in storage for years). My existing 2-channel set up is quite dated--a mid-90s NAD 713 AV receiver, an NAD CD player of more recent vintage, PSB bookshelf speakers circa 2005 and an 80's Harman Kardon T-45 turntable. The lack of bass has always been the most conspicuous shortcoming of this set-up and since i seem to have rediscovered the joys of listening to music, I want to add a subwoofer. My listening room is an open plan arrangement, the main listening area is about 12 feet square but there is no wall separating it from the next living space, so the room overall (which includes my kitchen) is roughly 12 x 30 feet, with hardwood floors. Music only, both pop and classical, I'm not seeking bone-rattling effects. I have been looking (online only) at the HSU ULS 15 MK2; also considering the (more expensive) SVS SB-3000 and the (less expensive) ELAC Sub3030. It's a bit frustrating not to be able to hear before ordering, but that seems to be what I'll end up doing. So, my first question: does the DSP sound adjustment software make a big difference? That's the attraction of the ELAC, and I gather there is something similar with the SVS, though it isn't clear to me what it does in the case of SVS. My second question: since a single subwoofer will be the only addition to my system in the immediate future, does the age of my other components create limitations that I should consider? The NAD receiver does have a mono sub out jack, though I'm not sure it has a setting to limit the bass to the bookshelf speakers when a subwoofer is attached, if that's important. Thanks in advance for any advice.
Here's all you need for a very reasonable price:

https://www.parts-express.com/dayton-audio-sub-1200-12-120-watt-powered-subwoofer--300-629
 
TLS Guy

TLS Guy

Audioholic Slumlord
The speakers are PSB Image B-25. Specs say they go down to 45hz +/- 3db. The SVS tool suggests setting a crossover of 60hz in a non-bass managed system (and recommends their own 2000 and 3000 series subs).
So this is the response of your speakers.


So yes, the F3 does look to be 45Hz, so 60 Hz would be the starting point for blending in a sub.

However I'm a little puzzled that you say there is a serious loss of bass. There is not a lot of musical information below 45 Hz.

So your problem could well be related to this.



Now the solid line plots the impedance of your speakers with frequency. The dotted line is the phase angle between voltage and current against frequency.

Now note there are a couple of dips to 4 ohms and one below four ohms. The big problem though is that the phase angle dips strongly negative three times, and at times where the impedance is below 6 ohms. Now when the phase angle gets around -45 degrees it really stresses an amp when the impedance is low and doubles current demands.

These speakers have to be classified as ones presenting a very difficult load to an amplifier. So I suspect that your current receiver is really struggling with this load, and giving you that 'weak in the wind' sonic presentation. I have noted this effect before.

I have to say these curves a highly unusual for two way bookshelf speakers. It is common in large towers.

So if you change receivers then you need to look at robust amplification.

If your needs are for only two channel music listening then I strongly suggest you look for a good vintage power and pre amp and do you own bass management.

The bad news is that the current crop of receivers are even less able to handle that type of load then older ones, and would be prone to blow up when presented with speakers like that.

So those speakers have excellent measurements sonically, but in order to get that, require very stable amplification. This is very unusual when we are talking about powering a couple of small two way bookshelf speakers.

I think this has a lot more to do with your presenting problem than the absence of a sub. Although with proper bass management and a fairly high crossover at 100 Hz, then the effects of a couple of the worst phase angle dips would be negated. So you will have to ponder your options carefully.
 
2

2channel lover

Audioholic Field Marshall
PS: If the conclusion is that I need to replace the old NAD receiver before adding a sub, I'd be happy to be pointed toward some recommended alternatives. Though my current unit is 5-channels, I only expect to use two channels in any future system, so perhaps a stereo receiver or integrated amp would be the logical choice.
I forgot what the budget was now, but you don't have to bust the budget on a new AVR...I like the Denon 3500 recommendation and have 2 happy friends that I referred to the same AVR...well one wanted instant gratification so he bought the 3600 locally. The room EQ, and bass management...like I mentioned...online music sources. It may seem like a waste to buy 5 channels to listen to only two, but when you get a stereo receiver with bass management, room eq (good luck with that)...you're in the ball park of a lower end 5 ch AVR with all of the features

Couple that with a nice sub...and you allow those PSBs to open up to their max potential.

Yes, a sealed sub will sound better than what you have now...There are others to consider...I'm partial to the HSU VTF series subs. VTF 2...12" $540...and the two bigger brothers...the 15" VTF3 mk5 $800...and the big daddy VTF 15H $900

If you can only do one at a time...I normally would so the sub first most of the time, but in your case, it may make more sense to get acquainted with the new AVR 1st since you wouldn't have bass management to use the sub anyway.

Good luck.
 
KEW

KEW

Audioholic Overlord
To get to the point, I can't accommodate a unit that significantly exceeds 17" width or 12" depth.
This is a huge barrier for upgrading the AVR!
First off, 17" nominal seems to be a defacto industry standard for width of audio gear.
I'm hoping you have an extra 1/4" or better to play with. As a quick check, I just measured some gear:
Denon AVR-4520CI is 17-1/8" Wide
Yamaha Receiver R-S700 is 17-1/8" Wide
Oppo BDP-103D BluRay Player is 16-15/16" Wide
Marantz VC-6001 DVD/CD changer is 17-3/8" Wide (this is a 5 disc changer, so this may just be as narrow as they felt comfortable making a 5 disc changer).

However, your maximum depth of 12" is very much at odds with TLSGuy's post about needing a robust power section. I don't know of any receiver that could qualify on both counts! That doesn't mean they are not out there!
There are some excellent stereo amps that meet your size constraints (including Quad amps which are excellent and something like 9.5" deep), but finding the pre-amp would be difficult (it may be impossible if you are looking for a quality RoomEQ for integrating the bass)!
 
KEW

KEW

Audioholic Overlord

Although with proper bass management and a fairly high crossover at 100 Hz, then the effects of a couple of the worst phase angle dips would be negated. So you will have to ponder your options carefully.
Dr. Mark, I know my solution does not meet your high standards for excellent audio, but if we assume his size restrictions and budget do not allow for a thorough revamp of his system, I need someone like you (with a sound knowledge of electronics) to check my approach to an incremental improvement.
I am not familiar with these, but Parts Express sells 100Hz speaker level high-pass filters (both 4 ohm and 8 ohm versions).
If I understand, he could put one of these before each of his speakers which would roll off the signal to them at 100Hz and set the low-pass filter on a sub at 100Hz to match. What I am not totally positive about is would this substantially reduce the load on the amp? And which one (4 or 8 ohm) would he want to get?
What do you think?
 
TLS Guy

TLS Guy

Audioholic Slumlord
Dr. Mark, I know my solution does not meet your high standards for excellent audio, but if we assume his size restrictions and budget do not allow for a thorough revamp of his system, I need someone like you (with a sound knowledge of electronics) to check my approach to an incremental improvement.
I am not familiar with these, but Parts Express sells 100Hz speaker level high-pass filters (both 4 ohm and 8 ohm versions).
If I understand, he could put one of these before each of his speakers which would roll off the signal to them at 100Hz and set the low-pass filter on a sub at 100Hz to match. What I am not totally positive about is would this substantially reduce the load on the amp? And which one (4 or 8 ohm) would he want to get?
What do you think?
One of those will really muck up the sound of his speakers. That is just a first order passive filter, with a huge inductor. For just one thing that will really alter the Q of his woofers, because of the series DC resistance to the woofer. To offer a product like that is to all intense fraudulent.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Because he has such space constrains he should look for a used Quad 34 pre amp which has a small profile. LP sound is superb from those. Then he can tuck a a Quad 405-2 power amp away out of sight. He needs a 405-2 because of his speaker load. He can then use that HSU crossover device he found to do his bass management. That will be neat, elegant and give far better performance than any receiver. He actually could use any decent two channel power amp he wants. Quad preamps are nice as they have such excellent LP play back.

Under his circumstances that will give him a first class system out of excellent vintage gear. His speakers will never have sounded so good.
 
KEW

KEW

Audioholic Overlord
Because he has such space constrains he should look for a used Quad 34 pre amp which has a small profile. LP sound is superb from those. Then he can tuck a a Quad 405-2 power amp away out of sight. He needs a 405-2 because of his speaker load. He can then use that HSU crossover device he found to do his bass management. That will be neat, elegant and give far better performance than any receiver. He actually could use any decent two channel power amp he wants. Quad preamps are nice as they have such excellent LP play back.

Under his circumstances that will give him a first class system out of excellent vintage gear. His speakers will never have sounded so good.
That would be great, but I got the impression his budget wasn't ready for a full revamp of his system!

Wait!
He has an older receiver which has a tape loop/monitor!
Isn't there a proper line-level bass management box he could slip in the loop? The Hsu one would work, but it does not have a sub output built into it!
Something like this?

@BeeTee , how far away are you from the speakers and how loud do you listen? One concern is that your receiver may be damaged. Has it ever tripped off with a thermal overload error or anything like that? NAD has a pretty good reputation, but yours is one of their least powerful units. Dr. Mark (TLSGuy) knows his stuff, however, if you are not one to rock out, the level you play your music at is a huge factor in how much current flows through the receiver!
Dr. Mark, are there any simple "layman" ways to test for problems with his AVR.
 
ski2xblack

ski2xblack

Audioholic Field Marshall
Wait!
He has an older receiver which has a tape loop/monitor!
Isn't there a proper line-level bass management box he could slip in the loop
Nope, the tape loop is upstream of the volume control. Pre-out/main-in is what he needs, which his NAD lacks (strange, as all their vintage stereo kit had 'em).
 
KEW

KEW

Audioholic Overlord
Nope, the tape loop is upstream of the volume control. Pre-out/main-in is what he needs, which his NAD lacks (strange, as all their vintage stereo kit had 'em).
DOH!
I know better!
Thanks for reminding me of the obvious. Unquestionably, I need it. o_O
 
B

BeeTee

Enthusiast
Wow, thanks so much for your serious consideration of my situation--greatly appreciated and I'm learning much. I'm stuck working today and this evening, I will respond further tomorrow...
 
TLS Guy

TLS Guy

Audioholic Slumlord
Doh!
I know better!
Thanks for reminding me of the obvious. Unquestionably, I need it.
I would hope so, after all the money we have spent on your education!

However the real problem the OP has is not lack of a sub, but his receiver. Pictures of that look suspiciously like a couple of units round the OP at that time. The amps are only 60 watts into 8 ohms. Under test they drop to somewhere around 25 watts and are distressed. They blow when pushed. Best place for them was in the bin.

He has decent speakers. Anytime I have heard PSB speakers I have been favorably impressed. To have a 3db point of 45 Hz from some small bookshelves like that is no mean achievement and they should not sound particularly lacking in bass.

The other point I would make is that amps are specked and tested into resistive loads. So specs, and measured results in reviews just tell you that, and NOTHING else. They do not tell you how it will behave into a load like the OPs speakers present.

I would bet if his speakers were driven by one of my Quad amps the resulting sound would be absolutely transformed.

So in this case the OP needs to start with robust electronics and not a sub. Unfortunately those speakers have expensive tastes as far as amps are concerned.

I would be very concerned the load those speakers present are calculated to send the current crop of receivers to the recycling zone pronto. Since this is an audio channel system my advice stands, that his best bet is to move to a good 2 channel power amp of at least 100 watts into four ohms 2 channels driven and a separate preamp. There is every chance he will not be looking for a sub after that.

Everything that ails an audio system can not be solved by adding a sub, or more and bigger ones, not by a long shot.
 
B

BeeTee

Enthusiast
Just dropping in quickly to say thanks again for the feedback--I've been consumed with work responsibilities this week, I will aim to get back here on the weekend in the hope of continuing (and reframing) the discussion in response to your kind attention. I hope you folks will still be around then...
 
TLS Guy

TLS Guy

Audioholic Slumlord
Just dropping in quickly to say thanks again for the feedback--I've been consumed with work responsibilities this week, I will aim to get back here on the weekend in the hope of continuing (and reframing) the discussion in response to your kind attention. I hope you folks will still be around then...
Ya, we are are all locked up and the key thrown away!
 
B

BeeTee

Enthusiast
Everything that ails an audio system can not be solved by adding a sub...
Those are wise words. First of all, the system as is actually sounds pretty good--while wondering about ways it might sound a bit better, I immediately reached for a subwoofer, since I only have the bookshelf speakers and I've always imagined that a sub would extend the dynamic range of the music. The careful attention that you folks (KEW, TLS Guy and others) brought to my request made me look at the issue more carefully. So at this point, I guess I'm looking for guidance about which element in the system would be the most logical place to begin upgrading, given the following. While I have no doubt that more modern and powerful electronics could improve the sound, I have not noticed obvious deficiencies with the amp (beyond a small gritty knob issue that seems to have be solved by deoxit). The amp easily powers the speakers to the loudest volume I ever use; I don't think I've ever turned the volume knob past the half-way point. The specific place where I have experienced a sense of something lacking has been with vinyl. The records sound enjoyable but the vinyl sound seems a bit compressed and the low-end relatively weak compared to other sources. Obviously, some of this is inherent in the medium. Nevertheless, I wonder whether there is more detailed and extended music to be coaxed out of the grooves. (Though I ignored my record collection for years, it was once a really important part of my life, and I still have well in excess of a thousand LPs.) Here's the existing system: turntable is a mid-80s Harman Kardon T-45, the cartridge is an Ortofon OM20. The stylus has not been replaced for years, but it is not very worn in terms of actual hours of play. The receiver, as you know, is an NAD AV713, vintage mid-to-late 90s. PSB B25 speakers on stands. I also have an NAD C546BEE Cd player attached.

In response to some questions above:

If I sit to listen critically I'm roughly 10 feet from the speakers. But in practice I'm often wandering around the room while audio is playing, including in the kitchen area about 25 or 30 feet from the speakers.

There is wiggle room with that 17 x 12 inch limit. I could squeeze in a unit that's 17 3/4" wide. Back to front is more complicated; As is, I could easily sneak in at least an inch on top of the back-to-front dimension, and worst case I could remove the back panel of the case to allow the connectors to be exposed. That would allow my furniture to accommodate most amps, though I'd prefer to avoid that for aesthetic reasons (and it might subtract a bit of rigidity from the case).

Budget: It'll probably be a slow process of upgrading, with the idea that I'll hold whatever I get now for decades. Let's say a budget of $1000 for the next purchase (though I could probably be talked into a higher limit if it is going to make a huge long term difference).

So, do you still think a new amp is the best move? Or a different phono cartridge? I can feel the floor opening beneath me: new amp, new turntable, new furniture, new house....
 
KEW

KEW

Audioholic Overlord
Those are wise words. First of all, the system as is actually sounds pretty good--while wondering about ways it might sound a bit better, I immediately reached for a subwoofer, since I only have the bookshelf speakers and I've always imagined that a sub would extend the dynamic range of the music. The careful attention that you folks (KEW, TLS Guy and others) brought to my request made me look at the issue more carefully. So at this point, I guess I'm looking for guidance about which element in the system would be the most logical place to begin upgrading, given the following. While I have no doubt that more modern and powerful electronics could improve the sound, I have not noticed obvious deficiencies with the amp (beyond a small gritty knob issue that seems to have be solved by deoxit). The amp easily powers the speakers to the loudest volume I ever use; I don't think I've ever turned the volume knob past the half-way point. The specific place where I have experienced a sense of something lacking has been with vinyl. The records sound enjoyable but the vinyl sound seems a bit compressed and the low-end relatively weak compared to other sources. Obviously, some of this is inherent in the medium. Nevertheless, I wonder whether there is more detailed and extended music to be coaxed out of the grooves. (Though I ignored my record collection for years, it was once a really important part of my life, and I still have well in excess of a thousand LPs.) Here's the existing system: turntable is a mid-80s Harman Kardon T-45, the cartridge is an Ortofon OM20. The stylus has not been replaced for years, but it is not very worn in terms of actual hours of play. The receiver, as you know, is an NAD AV713, vintage mid-to-late 90s. PSB B25 speakers on stands. I also have an NAD C546BEE Cd player attached.

In response to some questions above:

If I sit to listen critically I'm roughly 10 feet from the speakers. But in practice I'm often wandering around the room while audio is playing, including in the kitchen area about 25 or 30 feet from the speakers.

There is wiggle room with that 17 x 12 inch limit. I could squeeze in a unit that's 17 3/4" wide. Back to front is more complicated; As is, I could easily sneak in at least an inch on top of the back-to-front dimension, and worst case I could remove the back panel of the case to allow the connectors to be exposed. That would allow my furniture to accommodate most amps, though I'd prefer to avoid that for aesthetic reasons (and it might subtract a bit of rigidity from the case).

Budget: It'll probably be a slow process of upgrading, with the idea that I'll hold whatever I get now for decades. Let's say a budget of $1000 for the next purchase (though I could probably be talked into a higher limit if it is going to make a huge long term difference).

So, do you still think a new amp is the best move? Or a different phono cartridge? I can feel the floor opening beneath me: new amp, new turntable, new furniture, new house....
TLSGuy is a good guy for this question, he has a great familiarity of Vinyl (along with excellent (far, far better than mine) knowledge of everything audio)!
I will point out to you that Crutchfield has a great return policy (read it yourself to verify nothing has changed!) where you have 60 days to return gear for any reason (other than you abused it). If you do return, they will even pay the shipping from your house back to Crutchfield. They only charge a "$15 restocking fee".
Assuming that they have the gear you need, being able to try out an item before you are completely committed to it, is a great assurance!
Best buy has a 14 day return policy and Amazon has a 30 day return if it is a normal prime item. Amazon will "take over the world" soon enough so I will give my money to Crutchfield or others if it is reasonable to do so!
 
TLS Guy

TLS Guy

Audioholic Slumlord
Those are wise words. First of all, the system as is actually sounds pretty good--while wondering about ways it might sound a bit better, I immediately reached for a subwoofer, since I only have the bookshelf speakers and I've always imagined that a sub would extend the dynamic range of the music. The careful attention that you folks (KEW, TLS Guy and others) brought to my request made me look at the issue more carefully. So at this point, I guess I'm looking for guidance about which element in the system would be the most logical place to begin upgrading, given the following. While I have no doubt that more modern and powerful electronics could improve the sound, I have not noticed obvious deficiencies with the amp (beyond a small gritty knob issue that seems to have be solved by deoxit). The amp easily powers the speakers to the loudest volume I ever use; I don't think I've ever turned the volume knob past the half-way point. The specific place where I have experienced a sense of something lacking has been with vinyl. The records sound enjoyable but the vinyl sound seems a bit compressed and the low-end relatively weak compared to other sources. Obviously, some of this is inherent in the medium. Nevertheless, I wonder whether there is more detailed and extended music to be coaxed out of the grooves. (Though I ignored my record collection for years, it was once a really important part of my life, and I still have well in excess of a thousand LPs.) Here's the existing system: turntable is a mid-80s Harman Kardon T-45, the cartridge is an Ortofon OM20. The stylus has not been replaced for years, but it is not very worn in terms of actual hours of play. The receiver, as you know, is an NAD AV713, vintage mid-to-late 90s. PSB B25 speakers on stands. I also have an NAD C546BEE Cd player attached.

In response to some questions above:

If I sit to listen critically I'm roughly 10 feet from the speakers. But in practice I'm often wandering around the room while audio is playing, including in the kitchen area about 25 or 30 feet from the speakers.

There is wiggle room with that 17 x 12 inch limit. I could squeeze in a unit that's 17 3/4" wide. Back to front is more complicated; As is, I could easily sneak in at least an inch on top of the back-to-front dimension, and worst case I could remove the back panel of the case to allow the connectors to be exposed. That would allow my furniture to accommodate most amps, though I'd prefer to avoid that for aesthetic reasons (and it might subtract a bit of rigidity from the case).

Budget: It'll probably be a slow process of upgrading, with the idea that I'll hold whatever I get now for decades. Let's say a budget of $1000 for the next purchase (though I could probably be talked into a higher limit if it is going to make a huge long term difference).

So, do you still think a new amp is the best move? Or a different phono cartridge? I can feel the floor opening beneath me: new amp, new turntable, new furniture, new house....
Unfortunately enthusiasts like yourself are no longer well served by the market. I know exact;y what you are after. Your size constraint is also limiting.

Your turntable seems an excellent one. The cartridge is lower mid range. Your speakers I think are keepers, but they present an unusually difficult load to the amp for speakers of that type.

As I am fairly familiar with that range of vintage NAD equipment, I have to say I am not at all impressed with it and doubt it is getting anything like the best from those speakers. I get it they play loud enough, but that is not the whole issue by a long shot.

For the same reasons I do not think the current crop of receivers are a good choice for driving them.

If you want new with digital audio capability and the option of a sub with bass management then you actually only have one option. Yes, your choices are that limited.

It is this integrated amp from Outlaw Audio. It should easily be able to get the best out of your speakers. It meets your size constraints, and has bass management.

Your only other option is a good vintage rig, with separate pre amp and power amp. Your would have to organize your own bass management. I have the feeling that you are not the right guy to recommend that approach to. But if you are we can make recommendations.

This is where I recommend you start.

As funds permit, I would recommend a change of cartridge, since you have such a large LP collection. In the analog domain the gains are great as you move up the food chain.

As funds permit I would recommend purchase of this cartridge, the Ortofon 2M Black. Unfortunately the Shure cartridges are no longer available. This cartridge is widely regarded as the best MM cartridge currently available. I'm not a great advocate for moving coil cartridges.

After that it would be easy to add a good sub as funds and inclination permit.

Anyhow that is the order in which I would proceed. After that if you are unhappy that would mean a change of speakers. I think besting the ones you have would not be inexpensive.
 
KEW

KEW

Audioholic Overlord
The Outlaw receiver is 15" deep (and you need another 1" or so for plugs/cables). I don't think there is any Receiver or pre-pro that would meet the 12" deep target!
 
colofan

colofan

Enthusiast
Not sure of the surround material but you might have the lower drivers actually have started to fall apart on you after the number of years. Replacement drivers are a good lower cost solution to sub-woofer price.
 

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